Logitech Z-2300 : The Last of the Titans

[RishiGuru]

PART-I



INTRODUCTION

Logitech Z-2300
When Logitech introduced the Z-2300 way back in 2004, it was a THX certified premium quality top of the range product. The Logitech engineers in the lab where given a clear goal i.e. to create the best 2.1 multimedia speaker system for the computers. They were not concerned about the price, they were more concerned about the performance & quality which lead in using premium quality components, be it electronic components, speakers used, wooden casings of the subwoofers, plastic casings of the satellites and even the wires used to connect the components. Price was never an issue, performance was. This single mindedness of the engineers produced a unique product, and Z-2300 was born.

If you consider that way back in the year 2000 when Logitech was known as a cheap speaker manufacturer and could not even meet the standards of Altec Lancing let alone Klipsch computer audio products, they made a huge effort back then in order to make a big step forward and used better quality components for their THX certified audio system lineup than they have ever done before thus increasing cost. My "Price was never an issue, performance was" statement is in context of my above view. Today when we compare the Z-2300 from an el chepo manufacturer Logitech with the HiFi maker company like Klipsch producing Promedia 2.1 as a computer multimedia speaker system, you find both of them being in the same segment going head to head in terms of audio performance and in many occasions Z-2300 coming out as a clear winner. Atleast we have to give credit to Logitech that that could produce a multimedia speaker system that can meet the standards of a Klipsch product. I give full marks to Logitech only for this effort.



Logitech Z-623


Logitech introduced Z-623 in 2010 six years after Z-2300 reign. Actually I cannot recall of a 2.1 PC speaker that remained at the top of the performance charts for straight six years. They had to make the successor not because Z-2300 was getting old and becoming incompetent, believe me it is still is the king, but because the rival manufactures like Altec Lansing, Edifier, Creative, Sony etc are producing cheaper sets of same wattage and same configuration and labeling them as their premium product. Also 2.1 speakers sets are no more the cash cows of audio manufactures, rather these companies makes a lot of profit from selling the 5.1 & 7.1 speakers sets.

Z-2300 Specifications

Audio Quality Certification: THX certified
Total RMS Power: 200W [FTC Rated Power]
System THD: Better than 0.05% before clipping
Total Peak Power(RMS): 400W < 10% THD
Power distribution: 120 W (Subwoofer) + 2 X 40 W (Satellites)
Subwoofer: 120 W @ 8 ohms @ 10% THD @ 100Hz
Subwoofer Size (inch): 8
Subwoofer Type: Long throw
Satellites: 80 W (2 X 40 W) @ 8 ohms @ 10% THD @ 1kHz
Satellite Size (inch): 2.5
Satellite Type: Polished aluminum phase plug driver
Frequency response: 35 Hz - 20 kHz
Signal to noise ratio(SNR): @ 1kHz > 100dB
Sound Pressure Level (SPL): 117db
Subwoofer dimensions(HWD): 11" X 11" X 15"
Satellite dimensions(HWD): 6.75" X 3.5" X 6"
Total weight : 15 Kg

UNPACKING

The satellites & Control Pod neatly packaged in the box




SUBWOOFER



The subwoofer is huge, in every sense of the word. The behemoth measures 11” (H) X 11” (W) X 15” (D), and its output could rattle the paint off your walls.

To give a comparison of how big the subwoofer is, look at the picture below where the Z-2300 sub is kept aside Altec Lansing VS2421.



Subwoofer made of thick MDF


The wall of the sub is made of 16 mm thick medium density fiberboard (MDF) which is quite impressive. It has been further strengthened with internal clamps in the joints. This adds tremendous strength to the box in order to withstand the slamming, heavy duty sound waves produced by the bass driver. The subwoofer weighs 12 kilograms and is a back breaker for sure.

Actually, this subwoofer was designed for Z-560 way back in the year 2000. Z-560 was the first THX certified multimedia speaker system from Logitech and was a big gamble at that time. Nobody was quite sure how the market will react in accepting a high end computer speaker from this unknown brand. But it seems that the gamble finally paid off and ever since this Holy Grail subwoofer have been used in their THX certified speaker systems line up for the past decade as below:
Z-560 [first THX certified 4.1 system, launched in the year 2000]
Z-680 [first THX certified 5.1 system, launched in the year 2002]
Z-2200 [first THX certified 2.1 system, launched in the year 2003]
Z-2300 [second THX certified 2.1 system, with minor updations on Z-2200 launched in the year 2004]

Z-2300 Bass Driver


Z-2300 subwoofer has a front facing massive 8 inch long throw bass driver. It has a Rated Power Input of 80W and maximum power input capability of 160W.

This history of 8 inch bass drivers began when Logitech choose Tang Band as the OEM manufacturer for their first THX certified multimedia speaker system Z-560 way back in the year 2000. It used direct off the shelf 8 inch Tang Band W8-670C with rated power input of 80W, maximum power input capability of 150W having a max excursion capability of 7mm. I guess at the time of release, Logitech was entering a new domain in computer audio, changing their image from relatively ordinary PC speaker manufacturer to a high end computer speaker manufacturer, and was themselves not quite sure about how many units of Z-560’s they will be able to sell.

There is a department in Logitech that exclusively deals with audio products and are better known as Logitech Sound Central. The link to the website is provided here: Logitech Sound Central

They state: “We don’t simply buy parts off the shelf. We laser tune different types of drivers. We modify the shapes, experiment with materials, and use digital components to improve sound quality. Our goal is to deliver fidelity as close to the original sound as possible.”

Logitech Sound Central testing the bass driver of Z-5500


When Z-560 successor, Z-680 was launched in the year 2002, they shifted to an unknown speaker manufacturer which builds speakers in accordance to Logitech specifications.

I personally own a Z-560 & Z-2300. After minutely inspecting both the drivers of Z-560 & Z-2300, I found out

1) Both have same magnet size & weight thus having identical rated power handling capabilities.

2) Z-2300 bass driver have more excursion capability that that Z-560 ones, maybe 10mm [estimated] where Z-560 ones have only 7mm. This is evident since Z-2300 ones have slightly longer & elongated stamped steel basket section between the spider & the magnet compared to Z-560 ones, providing the space for more excursions capability.

3) The cooling efficiency of the Z-2300 bass driver with its bigger vented pole piece is significantly higher than Z-560 ones.

The bass driver of Z-2300 with even higher excursion capability than Z-560 ones will definitely offer better sensitivity & accuracy not to mention the ability to handle more power over its rated input power with better cooling efficiency. Later I found out that Z-2300, Z-2200 & Z-680 all used this new driver.

 

[RishiGuru]

PART-II

Look below at the increase of the hole diameter of the vented pole piece:

Tang Band Z-560 subwoofer with smaller vented pole piece


Z-680 aka Z-2200 aka Z-2300 subwoofer with bigger vented pole piece


Z-2300 Bass Driver










Comparing Z-2300's aka Z-680 monstrous 8 inch bass driver on the left with the Onkyo's 8 inch bass driver on the right.



Note: Normally people confuse this bass driver as used in Z-680, Z-2200 & Z-2300 with the Tang Band W8-670Q model. Though both units look near identical, Z-2300’s bass driver is different from the W8-670Q in the rear section. It became absolutely certain when my friend’s Z-2300 bass driver went dead and I have to personally contact TangBand via email to ask the model of the driver used in Z-2300 & its price. I also send them the above pictures of the driver to help them identify. To my surprise, they replied after inspecting the pictures sent to them, that this bass driver do not belong to them or in any way or represent any one of their models. But they did agree that they supplied W8-670C drivers for Z-560. So, you see Z-680, Z-2200 & Z-2300 are not TangBands. Prior, I was also the victim of this case.

The subwoofer enclosure also houses a patented “U” shaped exponentially increasing bass reflex port to produce distortion free deep and rich bass experience. The enclosure is very deep, which is obviously good from an acoustical standpoint.

Z-2300 Satellites

Z-2300 uses 2.5 inch polished aluminum phase plug drivers in their satellites and are beautifully crafted to look like a piece of art. The 12W satellite drivers that Z-2300 uses are again from an unknown speaker company and does not in any way relate to 3 inch Tang Band (W3-594SB) units. I estimate a rated power of 10W & a max of 20W. But since these drivers get audio frequencies ranging from 150Hz to 20kHz, the power handling capability increases by at least two times. So these speakers can handle anything between 20W to 40W.

Satellite Drivers

 

[RishiGuru]

PART-III



With the polished aluminum phase plug drivers helping to reduce the path length differences about the cone surface, you get a smoothing and reinforcing the frequency response, particularly in terms of the highest frequencies the driver is capable of. There is some thermal dissipation one gives up by doing this, but the phase plug itself can serve as a heat sink for the voice coil and magnet pole.

CONTROL POD



The control pod of the Z-2300 is quite simple and minimalistic, which I prefer. No fancy lights just a big volume knob, a bass control, a 3.5 mm headphone jack, power LED and a power button. You can keep the control pod on your desk where ever you like and the controls are very convenient.

Here are some pictures of Z-2300 control pod innards





AMPLIFIER DETAILS

Audio design has always been a subject that stirs the passions of most electronics engineers and a subject where the pursuit of perfection has many times comes before considerations of cost. That aside sometimes the simplest circuits can offer the best solutions in terms of cost and performance. Z-2300 houses the amplifier in their subwoofer assembly.

Power Supply

The power supply of an audio amplifier is of vital importance, since it provides all the juice required by power amplifiers to drive the big speakers. An underperforming power supply will seriously limit the performance of an amplifier.

The power supply consist of:

i) A center tapped toroidal transformer manufactured by Ten Pao International. This transformer is rated at 150.9VA with +/- 20.1VAC secondary, 3.75A.

ii) A metal cased bridged rectifier to provide full-wave rectification from +/- 20.1 VAC to DC.

iii) A pair of CapXon 10,000 uF, 35V capacitors one for + 20.1 VDC and the another for – 20.1 VDC acting as ripple filters in order to smooth the DC output.

Toroidal Transformer Details

Manufacturer: Ten Pao International Ltd.
Part No: Z-2200 EU
Model No: TOG433028F0
VA Rating: 150.9 VA [Confirmed by Ten Pao]
Primary Input: AC 230V/50Hz
Secondary Output Voltage: AC 20.1V x 2
Secondary Output Current: 3.75 A
Diameter: 95 mm
Height: 45 mm





A toroidal transformer uses a doughnut shaped core & is much slimmer than a conventional (EI) transformer. It has numerous advantages over EI type such as low weight, low hum, low noise and also being smaller in size than an equivalent EI type. On the downside they are much more expensive than a conventional EI transformer. But it is worth the pay since you get better performance. A toroidal transformer has so many other performance advantages over EI type that it is hard to describe here other than to provide the performance ratio. Toroidal : Conventional(EI) :: 158 : 5 . It you want to know more in details go to the link below: Bryston Transformers

The Bridge Rectifier


The Ripple Filter Capacitors



The transformer used here is rated to have an output of two times 20.1VAC when it has its rated load. So its resistance has already dropped the open circuit voltage and its peak will be 1.414 times higher which happens to be 28.4VAC. A single rectifier here drops it by 1VDC to 27.4VDC and smoothing the ripple by the power capacitors drops it by another 1.4VDC to 26VDC.

So, DC voltage supplied by the power supply is +/- 26 VDC, the current being 3.75 A.

Amplifier Chips

Z-2300 uses four Class-AB power amplifiers from STMicrolectronics. STMicrolectronic is a very renowned name in audio amplifier market.

The amplifiers used are:

i) A Japan Radio Corporation’s JRC-4565 operational amplifier. JRC-4565 is a dual op-amp which means it has two op-amps inside it to handle stereo channels.

ii) Two voltage regulators a 78M18 and a 79M18 supplying +/- 18 VDC respectively to feed JRC-4565 op-amp from the +/- 26.4 VDC power rail.

iii) One STMicroelectronics, Class-AB, 60W, TDA7296 power amplifier for each of the two satellites while the other two STMicroelectronics, Class-AB, 80W, TDA7295 are bridged together powering the subwoofer.

JRC-4565 operational amplifier



78M18 and 79M18 voltage regulators

 

[RishiGuru]

PART-IV

Logitech Z-2300 Amplifier Innards













Reasons for using Class-AB Power Amplifiers

A quick look at many new low power speaker amplifiers on the market highlights the move to Class-D audio performance, but when it comes to low distortion and low noise and best sound quality, Class-AB still has the edge.

Class-AB architecture offers a signal to noise plus distortion ratio of up to 10 times better than its equivalent Class-D neighbour as well as providing a much simpler architecture which can be tweaked as required, without the need for reactive filter components on the output and the electromagnetic radiation resulting from an output stage switching at a few hundred kHz. Class-D amplification has inherent distortion in it and therefore is predominantly used in lower bandwidth amplification like in subwoofers. In other words it is quite impossible for a Class-D to achieve the level of linearity in frequency response produced by a Class-AB amplifier.

Ultimately it comes down to what you want, for efficiency and cost effectiveness Class-D are best, but if you are ready to sacrifice some efficiency & increase cost for the sake of sound quality then Class-AB are the best. In other words Class-A amps sound the best, cost the most, and are the least practical. They waste power and return very clean signals. Class-AB amps dominate the market and rival the best Class-A amps in sound quality. They use less power than Class-A, and can be cheaper, smaller, cooler, and lighter. Class-D amps are even smaller than Class-AB amps and more efficient, because they use high-speed switching rather than linear control.

The most important reason behind which multimedia speaker manufactures are switching from Class-AB to Class-D is to increase profit margin. Class-D is very cheap to produce and does not need require a big extruded aluminum heat sink or expensive toroidal transformers. They are basically switching power supplies but utilize pulse width modulation so as to be able to reproduce and amplify an alternating current. There are ok for subwoofers, but I honestly think that it is ridiculous to use a Class-D amplifier in a high end studio monitor.

In short, Class-D amps are more efficient but are only good for low frequencies applications like subwoofer amplification. Class-AB amps can be used full range amplification i.e from 20Hz – 20kHz. Class-D amps cannot be used on highs frequency response because they only produce square waves because of the technology involved, so they will make your highs sound lifeless and tinny. Class-AB amplifiers produce full variable signals and can capture subtle nuances better, sound warmer and generally have more depth in their sound.

Principles of Amplifier Operation in Z-2300:

1) A stereo audio signal comes in through the green 3.5mm audio connector with the control pod.

2) In the control pod, the signal passes through the main volume logarithmic potentiometer for attenuation.

3) This attenuated audio signal is then send down from the control pod to the subwoofer enclosure through a D-Sub connecter where the amplifier module exists. A JRC-4565 operational amplifier first receives this audio signal. The JRC-4565 having stereo handling capability distributes the audio signal into two places:
a) To the left and right satellite TDA7296 power amplifiers and then subsequently to the 2 satellite speakers.
b) Back up to the remote through the D-Sub connector.

4) Inside the remote, the stereo audio signal is split again:
a) To the headphone jack
b) To the subwoofer bass volume potentiometer (where it is combined to mono at this point)

5) Audio signal output from the subwoofer bass potentiometer finally gets fed back into the subwoofer enclosure through the D-Sub connector to the bridged TDA7295 subwoofer power amplifiers and then to the bass driver.

The four power amplifier chips operate at 8 ohms load in Z-2300 amplifier module.

Technical analysis of Class-AB, STMicroelectronics of TDA7295 & TDA7296 DMOS Audio Amplifiers

The TDA7295 & TDA7296 are both monolithic integrated circuit in Multiwatt15 package, intended for use as audio class AB amplifier in Hi-Fi field applications (Home Stereo, self powered loudspeakers, Topclass TV). Thanks to the wide voltage range and to the high out current capability it is able to supply the highest power into both 4 & 8 ohm loads even in presence of poor supply regulation, with high Supply Voltage Rejection. The built in muting function with turn on delay simplifies the remote operation avoiding switching on off noises. TDA7295 have a maximum output capacity of 80W while TDA7296 has 60W.

Remembering that the power supply of Z-2300 is +/- 26 VDC, the current being 3.75 A.

TDA7296

Output Power vs. Supply Voltage @ 8 ohms



Looking at the Output Power vs. Supply Voltage graph of TDA7296 above, we see it can produce 38W of power at 26 VDC at a respectable 0.5% THD.

So, at +/- 26 VDC --> 38W @ 0.5% THD @ 8 ohms

Distortion vs. Output Power @ 8 ohms



Distortion vs. Output Power graph of TDA7296 shows that at 38W @ 0.5% THD @ 8 ohms @ 26 VDC it starts to clip & distort. So in order to produce distortion free sounds this id the effective maximum of the chip.

Effective maximum of TDA7296: 38W @ 0.5% THD @ 8 ohms @ 26 VDC

Power Dissipation vs. Output Power @ 8 ohms



The Power Dissipation vs. Output Power graph of TDA7296 shows it as a very efficient Class-AB amplifier. At 38W @ 0.5% THD @ 8 ohms @ 26 VDC, the power dissipation is just 12W. This means if 50W is fed by the power supply to this TDA7296, it will deliver an output of 38W to the speaker whereas only 12W will be lost as heat.

So, this TDA7296 have an efficiency of 76% when it is producing 38W @ 0.5% THD @ 8 ohms @ 26 VDC. The power dissipation increases when the output power is reduced to half.

TDA7295

Two TDA7295 are bridged together into an 8 ohm load to power the subwoofer. Each of these TDA7295 sees effectively a 4 ohm load when bridged into an 8 ohm load. If you bridge an amplifier, the available power is the power of a single channel into half the load impedance multiplied by two.

Output Power vs. Supply Voltage of a single TDA7295@ 4 ohms



Looking at the Output Power vs. Supply Voltage graph of a single TDA7295 above, we see it can produce 65W of power at 26 VDC at a respectable 0.5% THD.

So, at +/- 26 VDC --> 65W @ 0.5% THD @ 4 ohms

Now if we bridge a pair of TDA7295, the available power is the power of a single channel into half the load impedance multiplied by two. Since TDA7295 produces 65W into 4 ohms, bridged it will produce 65 X 2 = 130W into 8 ohms.

So, at +/- 26 VDC a pair of bridged TDA7295 will produce --> 130W @ 8 ohms

 

[RishiGuru]

PART-V

Distortion vs. Output Power of a pair of bridged TDA7295@ 8 ohms



Distortion vs. Output Power graph of TDA7295 shows a pair of bridged TDA7295 after 100W starts to clip & distort. So in order to produce distortion free sounds this 100W is the effective maximum of the bridged TDA7295.

Power Dissipation vs. Output Power of a single TDA7295@ 4 ohms



The Power Dissipation vs. Output Power graph of TDA7295 shows it as an efficient Class-AB amplifier. At 65W @ 4 ohms @ 26 VDC, the power dissipation is 30W. This means if 95W is fed by the power supply to this TDA7295, it will deliver an output of 65W @ 4 ohms to the speaker whereas 30W will be lost as heat. In a bridged format it will deliver an output of 130W @ 8 ohms to the speaker whereas 60W will be lost as heat.

So, a pair of bridged TDA7295 have an efficiency of 68% when it is producing 130W @ 8 ohms @ 26 VDC. The power dissipation increases when the output power is reduced to half.

Looking at the above figures its seems that Logitech’s claim of 200W is true, since each satellites will have 38W while the subwoofer will get 130W which sums up to: 38 + 38 + 130 = 206 W @ 8 ohms @ 26 VDC

But, unfortunately that is not the case.

Z-2300 amplifier’s continuous power output capability

In order to produce 200W of continuous power, an amplifier will need a transformer that is capable of to deliver a minimum of 1.27 times the claimed wattage. Since Watt is volts multiplied by ampere, 200W of output requires 254 watts or 254VA transformer as a minimum requirement.

So, Z-2300’s supplied 150.9VA will produce a maximum of: 150.9/1.27 = 119W =~ 120W of continuous power @ 8 ohms @ 26 VDC

Since the ratio of power distribution between the subwoofer and the satellites are in the order of 1.71:1, the subwoofer will get 76W of continuous power while each satellite gets 22W of continuous power.

This becomes even more evident from the fact that the bass driver has a rated input power 80W, while the satellite speakers can handle anything between 20 to 40 watts.

The Total RMS Continuous Output Power of the four amplifier chips = 50(TDA7295) + 50(TDA7295) + 30(TDA7296) + 30(TDA7296) = 160W whereas the Total RMS Continuous Output Power of these four amplifier chips is 120W for Z-2300 since the the power supply limits the maximum power output.

Also these amplifiers will produce a lot of distortion & noise at the peak 160W power output. So, in order to produce distortion free, linear sound the amplifiers generally needs to reduce its output peak power by 25% or more. Using an amplifier with some extra “headroom” will help assure that only clean, undistorted power gets to your speakers. Reducing the maximum power from 160W to 120W Z-2300 creates a 25% headroom and justifies the stated system THD of better than 0.05% before clipping & signal to noise ratio of > 100dB.

Discrepancies about Power Output Figures

Remember that most audio amplifiers do not have power supplies capable of driving their rated power continuously. This holds absolutely true for all computer multimedia speakers systems & consumer home audio products. Only HiFi systems costing a lot of money have power supplies that can match the continuous power rating of the amplifiers.

This is because music is not like a continuous sine wave. It has peaks of intensity, then relatively quiet periods. If music has a 20dB dynamic range then if the peaks are 200W, the average power is probably around 5W.

A transformer can sometimes go well beyond its rated power output for small amount of time to handle these peaks of intensity. For example the 150.9VA transformer of Z-2300 can go up to 180VA to handle the peaks & produce 140W power for that moment.

If even further power is required to handle this peaks of intensity, say 200W, then the additional 60W is supplied by the two large 10,000uF, 35V power supply filter capacitors of Z-2300 for this short period of time. The filter capacitors can charge back up during the relatively quiet periods.

So the 150.9 VA transformer of Z-2300 is perfectly capable to deliver 120W of continuous power & can easily handle peaks reaching 200W.

That is the reason why Logitech states that Z-2300 have a Total RMS Power of 200W. Look at the absence of the “continuous” word. Except HiFi systems, you will always find these consumer audio companies talking about “FTC Rated Power”,“Total RMS Power”, “Power”, “Total Peak Power”, “System Power”, “Music Power”, “Peak Music Power Output (PMPO)”,…………….. and the list goes on. But you will never find them talking about “Continuous Power” which happens to be the actual power of the amplifier.

Why Z-2300 is still the king of all 2.1 Multimedia Speaker System

Z-2300 is capable to produce 120 watts of continuous power which is a lot of power for a 2.1 PC speaker. Also, it is way more powerful than any of its competitors.

Look at the two shots of the Logitech Z-Cinema 2.1 speaker system power supply.



Take at even closer look at the main component of the Z-Cinema's switching power supply :



It is clearly stated, MAX TOTAL OUTPUT POWER 83.3W

Z-cinema’s switching power supply is capable to deliver a maximum of 83.3 watts which equates to 75 watts of continuous power from the amplifier. Also switching power supply cannot be overloaded the same way as transformers. In comparison, Z-2300 toroidal transformer alone is capable to produce 150.9 watts of power, not to mention it can even go up to 200W with the help of its internal capacitance & power supply filter capacitors to handle transient peaks on demand. So, on an average Z-2300 have 45W more than Z-Cinema. Same theory goes for the Z-2300 successor Z-623 which I believe is down by 40 watts or so.

Another famous example is Sony, notoriously known for their power out figures. Consider the case of Sony SRS DB-500 with 300W power output claim. A very famous website did a complete tear up of this DB-500 only to find out that the power supply can produce a mere 65 watts. So how does a 65W switching power supply produce 300W? Well even Sony is unable to answer this question.

So, the more you dig, the more you find out these power figures are marketing jargon, rather than true figures on which one can measure the performance of an audio system.



THX CERTIFICATION

THX stands for Tomlinson Holman’s eXperiment. A THX Certified Multimedia Speaker system is designed for those who crave the power and performance of home theater and studio sound at the desktop.THX certification recreates peak, Reference Level quality at your desktop listening position.

What is Reference Level? THX Reference Level, a setting designed to mirror the exact volume level used by movie makers and sound artists in the studio. When you are watching a movie on a THX Certified Multimedia Speaker System, you experience every sound element exactly like it was produced by the filmmaker—with the same fidelity, detail and clarity.

Speakers that can achieve THX Reference Level is no simple task. It requires a tremendous amount of power to drive an audio system effortlessly without clipping or distorting. THX Certified Multimedia Speaker Systems are designed to recreate Reference Level with minimal distortion.

THX worked closely with Logitech during product development, ensuring the two-satellite and subwoofer Z-2300 & Z-623 speaker system was meticulously mapped to THX design standards. Then, THX performed more than 400 bench tests, including frequency response, noise, distortion and power. The result is a THX Certified Multimedia Speaker system that delivers THX Reference Level sound pressure and fidelity – letting you hear every bass note, sound effect and dialogue as it was created in the studio.

Performance Benefits:
400 Bench Tests: THX acoustic and electrical bench tests ensure accurate and powerful audio performance.
THX Reference Level: Designed to mirror the performance characteristics of professional studio speakers, recreating peak, THX Reference Level quality.
Wide Bandwidth: Low frequency extension of satellite speakers ensures a smooth and balanced audio experience when sound pans from satellites to subwoofer.
Desktop Engineered: The Logitech Z-2300 or Z-623 are perfect for PC gaming, podcast production, audio and video editing, and enjoying music and movie applications on your desktop.
PERFORMENCE

1) QUOTES FROM DIFFERENT WEBSITES

i)Tomshardware

"Pump Up The Volume With 117 DB SPL

The response showed good balance and remarkable regularity in the midrange of up to 10 kHz. After that, performance slipped a little, which is to be expected from full-range drivers. Obviously the low end was nice and deep, which is normal for an enclosure of this size equipped with a good woofer and amplification. The 2300 isn't open to much criticism in this department."

SPL Figure Graphs

Satellites


"Response was remarkable in the upper part of the spectrum, even if the third-octave weighting linearized it somewhat. The hiccups in the lower end of the spectrum were largely due to the room where the measurements were made and should be ignored."

Subwoofer


"The 2300 handles the entire lower register. Like its predecessor, it can reproduce very low frequencies without weakening.

The Z-2300, based on Logitech's 2200, will serve as a reference point in the world of high-performance 2.1 speakers. While we would have preferred to see the satellites offer two-way drivers, the final result is that the speakers are at the high end of the quality spectrum. The 2300 thus represents one of the rare possible choices in this product sector for those who seek the best in the category."

ii) Tech-Labs (Russian)

Frequency Response

"Subwoofer little nedotyagivaet to lower the declared value, although both show a great result - 45 Hz. However, his characterization is not perfect, we can state a clear peak and the absence of a "shelf". The satellites, show a fantastic uniformity. Over the entire operating range it does not exceed ± 2.5 dB. For full range satellite speakers in the multimedia speakers category, such a result can be considered the supreme achievement."

Harmonic Distortion

THD Subwoofer

"THD of the subwoofer is very low even at high volume, they do not exceed 10%."

THD Satellites

"The tiny full range drivers perfectly wins back a wide frequency range, it develops impressive power too."



Fs = 42.95 Hz
Re = 7.80 ohms [dc]
Le = 7328.42 uH
L2 = 3120.63 uH
R2 = 52.25 ohms
Qt = 0.52
Qes = 0.57
Qms = 6.49
Mms = 50.81 grams
Rms = 2.112233 kg / s
Cms = 0.000270 m / N
Vas = 10.35 liters
Sd = 165.13 cm ^ 2
Bl = 13.755757 Tm
ETA = 0.14%
Lp (2.83V/1m) = 83.66 dB

"The resonant frequency is quite low, only 42 Hz. In sum, with a low Q factor is comparable to the use of acoustic design. Also, thanks to a massive system of magnetic head has a truly outstanding power factor."





"On set of indicators above, our assessment of today will be strictly positive. Z-2300 has an excellent manufacturing quality and very easy to use because of the remote volume control. The sound quality which i am not afraid to say, the highest. Massive subwoofer reproduces deep & rich bass that perfectly complemented by bright sounding satellites. Despite the relatively small size, power acoustics really high, we can say is very high. According to test results Logitech Z-2300 receives the award "Editor's Choice" in its class.

iii)CNET

"Editor's Rating: 4/5
Design : 9/10
Features : 9/10
Performance : 9/10

The Good: Outstanding audio quality; streamlined, efficient design; adapter for game consoles.

The Bad: Upward-firing satellites not adjustable; hardwired cables.

The Bottom Line: Logitech's Z-2300s have been on the market for more than half a decade, but these PC speakers still pack a sonic wallop."

iv) 3DXtreme

"A set of Speakers is hard to review, because there is no way to present comparisons, charts and graphs. Here is what we can say – for about $110 I have not heard a better set of speakers at this price point. We’ve reviewed a few budget sets of speakers that just fell short in the sound category lacking clarity and bass. When this set came along it was like a breath of fresh air. It may not have the volume or the power of the Z-6800 (which I also have) but on their own they sound amazing. Watching movies, listening to music and gaming is all a great experience with these speakers. Keep in mind they are only 2.1 channel speakers however this set of speakers has the Lucas THX certification – I’ve found that speakers with this certification to be a notch above the rest of the other products found on the market. Maybe I’m spoiled by Logitech and their speakers but to me this would be a worthwhile $100 purchase for anyone looking to get the most for their money. Logitech even throws in an adaptor that will allow the user to connect these speakers directly to a DVD player or game console.

Pros
Great sound.
Incredible bass.
SoundTouch with headphone jack.
Logitech quality.
Cons
Short wires on the satellite speakers
"
v) Bildochljud.se

"Sound Quality [Translated using Google Translate]
Here we are really surprised. Logitech's holding is not so much from the crowd in a negative sense as we feared. The sound will not be near the B & W's or Harman / Kardon, but it actually costs Z-2300 just a fraction too. If we compare with Altec Lansing, we are actually prepared to say that Logitech do better. The balance between the satellites and subwoofer is better here. You can almost play as loud as you want and the subwoofer has a great rumbling that matches the satellites well. We heard no distortion when the volume was turned up properly and balance, like I said very good.Logitech handle sensitive music and hard rock in the same fine manner. This is simply a cheap alternative that provides excellent value for money. No one style icon, but in short, a good sound for a small amount. We like the Z-2300."

vi) pocketnow.com

"OVERALL IMPRESSION
I've always been partial to offerings from Klipsch - I've owned many of their products, and to me they represent a very high level of quality. I expected the ProMedia 2.1 THX system to remain the king on the block even with, but as indicated by the ratings above, Logitech has brought to the market the next champion in high-end 2.1 multimedia audio namely the Z-2300."

2) MY PERSONAL THOUGHTS

Music: Throughout my 2 years with Z-2300, one thing became very clear; these are very neutral sounding speakers. What is produced by these speakers is very smooth, and very pleasant to listen to. The one thing that does come to mind when listening though is power. Z-2300 is capable of producing 117 dB which is a world record for a 2.1 multimedia speaker system. The subwoofer lets itself be known with its slamming tight & precise bass which at times are powerful enough to knock the wind out of your lungs. The satellites feature a nice, natural sound with excellent representation. If the user wants, they can boost the subwoofer levels through the roof though my ears will be bleeding by then.

I am dealing with one of the best solutions for pure listening pleasure, with a clean sound devoid of any colorings, embellishment or ornamentation in the sound, commonly found in Altec Lansing and Creative speaker systems. Now I can easily hear many of the previously obscure details in the compositions of a complicated music composition, and can clearly set apart all the instruments used in the music composition, thus I am able to focus not only on the primary instrument, which is audible, but also on the fact that what instrument I want to hear.

Even though these are not two way satellites, the phase plug allows the 2.5” driver to more accurately reproduce the high end of the frequency spectrum. There is no background noise with these speakers, and definitely none of the hiss that my Altec Lansing MX-5021 suffered from. The analog input was very clean, and it was able to reproduce the sound with great accuracy.

Movies: These speakers are exceptionally clear at reproducing dialogue, as well as action, in a wide variety of movies. Even when there is a lot of action and music on screen, dialogue is never drowned out, nor does it get muddy or indistinct. The lack of any kind of hiss also helps in playback, as the softer, more subtle scenes draw the viewer into the movie. The satellites do an outstanding job of reproduction.

When the action gets heavy, the subwoofer really kicks in. The bass is tight and strong, and it will make a user’s chest thump if the content calls for it. Low end effects can really help to heighten the tension of a scene, as well as help to expand the overall environment. The subwoofer on these speakers is able to handle nearly every explosive scene thrown at it. Never once did it sound like the subwoofer bottomed out, or sound strained, or even chuffed. The ported design is surprisingly quiet, considering in other designs I have heard quite clearly the air moving in and out. Overall, for a 2.1 set of speakers, these turned out to be quite good for movie reproduction.

Games: This is probably the area where these speakers excel the most. The satellites are very clear in gaming, and their mid-bass is very present, but not overpowering. High frequency sounds are usually not present in most games, so the lack of a tweeter here does not affect gaming performance one bit. The satellites are able to provide excellent sound in a variety of gaming situations, and the ability to accurately reproduce the HRTF effects makes for a very immersive experience.

The subwoofer really gets a workout from many of the new action games, and it keeps asking for more. In titles such as Need for Speed Undercover, the subwoofer plays a very large part in the action.

VERDICT

Z-2300 is hitting the end of the production cycle. It is the last of the titans which is finally going to take slumber. It has definitely the upper hand over its opponents namely Logitech Z-623, Altec Lansing MX-6021, Sony SRS DB-500, Edifier S530, Klipsch Promedia 2.1 & Creative Gigaworks T3 in terms of performance. Also Z-2300 is the clear winner in terms of performance/ price ratio.

When you put the Z-2300 in the above equation, everything falls loose. Z-2300 is like a lion among a herd of cattle’s named Z-623, DB-500, S530, Promedia & T3.

1) None of the above sets have the power output capability of Z-2300. Z-2300 is the loudest of the lot and makes the opposition eat the dust.

2) Z-2300 has wonderful power reserve in the amplifier & thus do not distort even at full volume. Z-623 & all the other sets distorts at full volume.

3) In terms of music representation Z-2300 is second to none. Since Z-2300 uses Class-AB amplifiers, the sound produced by Z-2300 is more natural, very well defined & represents the true analog nature of the human voice. Both male & female voices are excellently represented in Z-2300. In contrast Z-623’s Class-D amplifier lacks a little bit of the natural feel & warmth in the sound as found in Z-2300 and represents more that of MX-6021 & DB-500 in their sound characteristics. The subwoofer has tight bass but the overall bass of the Z-623 is not well defined. A system with Class-AB amplifiers (as in Z-2300) will produce bass which is a little less deeper than a Class-D of Z-623, but the bass will be much more defined & accurate and also feel more natural & real.

For example, playing the track "Chant" of the band Foreplay, I noticed that the kick drums of that track produce "boom boom boom" on the Z-623. Playing the same track on Z-2300, the kick drums sounded "booouuumm booouuumm booouuumm" which happens to be the actual sound of kick drums. In contrast, Z-623 bass goes a little deeper but is less natural & neutral.

If you really need a high end 2.1 THX certified multimedia speaker system don’t waste any more time and get a Z-2300 while it is still available. If it not available then only greet the new champ of the block, Logitech Z-623.

 

[RishiGuru]

Completely revamped the main review of this thread. Take a look as many new views, insights & technical aspects have been added while complete measures have been taken to trim the excessive fat. Still I admit, it is quite lengthy.

Views & remarks will be highly appreciated.

Regards, Rishiguru

 

[MEgamer]

class D is getting far more popular these days,
class D would be the right choice for low frequencies speakers and even high end studio subs, they are becoming far much better now, high end receiver/amps like ones from pioneer, use ICEPower from B & O, and extremely high end manufacturers martin logan, recently made a class D mono block amp.

effeciency is very important for speakers like subs, since heat is a major factor in its performance, so class D again would be the correct design decision.

i dont agree with u in the slightest for the class AB being slightly warmer. neutral sound is what u really want to aim for anyway, if anything warm sound is a con.



For example, playing the track "Chant" of the band Foreplay, I noticed that the kick drums of that track produce "boom boom boom" on the Z-623. Playing the same track on Z-2300, the kick drums sounded "booouuumm booouuumm booouuumm" which happens to be the actual sound of kick drums. In contrast, Z-623 bass goes a little deeper but is less natural & neutral.

^ are u sure this isnt just due to tightness of the bass?? if the z-263 one can hit deeper, but seems to have 'shorter' BOOMs, then this is good thing on the z-623 isnt it? i think the z-2300 booms for longer, due to slow response on the transients, which is common on poorly ported subs.

i have also heard that the z-2300 do distort a lot at least 50% volume, according to users on youtube who has uploaded their OWN vids of their subs.

IMO i think u wrote a little too much for a computer speakers, but this will sure help some others out there.

^(on what i wrote) this seems like a review.

 

[RishiGuru]

Very nice comments MEgamer and also very informative.

You not only pointed out the difference in our views but also provided a valid reason why which seems to be justifiable. Member like you are very rare in forums nowadays, mostly are of :

"I am right & you are wrong"
or
"My system will blow yours to the moon"

type.

I completely agree that Class-D are great for subs nowadays. They needs a lot of power & Class-D are very efficient to provide 90% of what they consume.

I do differ from you that the high frequency response are identical for both Class-AB & Class-D though. I think there is still a little bit of difference.

As of now you will only find a Class-D amplifiers costing a earth rattling $45,000/ pair monitors going head to head with $40,000 Class-AB/ pair monitors. The company is demanding that amount of money since it is spending millions of dollars to bridge the gap between the two in order to see better profitability in the near future.

When you go down the price range, you will find Class-AB amps still rules. Look at any quality active bookshelves costing less than $500, 95% of them are still using Class-AB.

Regarding the bass character of Z-2300 & Z-623.

Z-623 have tighter bass than Z-2300. Not by a huge margin but a little bit. You can feel that. Z-2300 bass on the other hand is more refined & defined by a little margin over Z-623. Both have their merits & demerits.

A music lover will go for the Z-2300, where as the Z-623 will be great for games & movies with a lot of explosions.

 

[kimpeters]

Completely revamped the main review of this thread. Take a look as many new views, insights & technical aspects have been added while complete measures have been taken to trim the excessive fat. Still I admit, it is quite lengthy.

Views & remarks will be highly appreciated.

Regards, Rishiguru

I found your review extremely thorough & informative. I own this speaker system & absolutely love the quality & richness of the systems sound, I only use them for Music play of my iTunes digital library (full spectrum of genres). Recently the right speaker began to cut in & out randomly, a light tap to the top of the cabinet seem to work for awhile...but now it has completely cut out?? I LOVE this system & would prefer to replace or repair the speaker vs searching out another system. Logitech no longer has replacement parts etc for this older product. What would you recommend or suggest?
I would appreciate any advice you could provide since you have investigated this product so thoroughly & appreciate it's superior characteristics & price point. Please note: I would be willing to purchase a new system if I could be assured of the same quality/functionality in a similar or even higher price range.
Thank you for your attention;
Kim Peters
Reply to: kimberlypeters@shaw.ca

 

[surtitanuj]

HI Rishiguru,

I have sent one private msg to your logitech id but there is no response from your end and fortunately I found you on tomshardware which I am using from last so many years. I have sent one private msg on your tomshardware as well. A humble request to go thru its an sos from Me

thanking you

Very nice comments MEgamer and also very informative.

You not only pointed out the difference in our views but also provided a valid reason why which seems to be justifiable. Member like you are very rare in forums nowadays, mostly are of :

"I am right & you are wrong"
or
"My system will blow yours to the moon"

type.

I completely agree that Class-D are great for subs nowadays. They needs a lot of power & Class-D are very efficient to provide 90% of what they consume.

I do differ from you that the high frequency response are identical for both Class-AB & Class-D though. I think there is still a little bit of difference.

As of now you will only find a Class-D amplifiers costing a earth rattling $45,000/ pair monitors going head to head with $40,000 Class-AB/ pair monitors. The company is demanding that amount of money since it is spending millions of dollars to bridge the gap between the two in order to see better profitability in the near future.

When you go down the price range, you will find Class-AB amps still rules. Look at any quality active bookshelves costing less than $500, 95% of them are still using Class-AB.

Regarding the bass character of Z-2300 & Z-623.

Z-623 have tighter bass than Z-2300. Not by a huge margin but a little bit. You can feel that. Z-2300 bass on the other hand is more refined & defined by a little margin over Z-623. Both have their merits & demerits.

A music lover will go for the Z-2300, where as the Z-623 will be great for games & movies with a lot of explosions.

 

[bshoc7]

Hi, so I was just wondering what the maximum voltage output is to the just subwoofer speaker. I read your article, and I was still a little unclear. Thanks so much!