Wonderful Interview with Mark Mozgawa (WHT Speakers/PSC Audio)

Over the last 3 years I have been listening to some loudspeakers which made me rethink my entire audio experience and it had me convinced that the most important components in the overall sonic experience are (1) the loudspeakers and (2) sonic quality of the room.

Those 2 components are the most crucial elements that will make all the difference. You simply cannot ignore them if you want the best results.

I have for the last 10-15 years searched for the ultimate loudspeaker that would fit in a standard room and will look smart and attractive at the same time. It seems like an easy enough tasks, since there is an incredible amount of gear on the market, but it is in fact quite difficult since the really good horn systems are very big and have their own problems in standard rooms.

And a loudspeaker HAS to be efficient, nothing else is even considered anymore.

That’s when I discovered the Australian speaker brand called WHT which has completely changed my system of belief.

These loudspeakers are 95 -102 db with 8-12 Ohm impedance, just perfectly suited to the best amplifiers, both tube and transistors. Even though I am a ‘tube’ man at heart – I was amazed at just how incredible they were on my OTL amplifiers (my 15 years old Graaf GM 20 OTL just crushes some very cool new “wonder” amplifiers). Now I’m also using the Aries Cerat Collatio II 20w OTL that just sounds incredible.

Mark Mozgawa, the founder and owner of WHT loudspeakers had for the last 15 years worked to fine-tune those speakers to the incredible quality that it’s hard to describe until you actually hear it.

They have just a such a natural ‘live performance’ feeling with any kind of music you choose to play, that I came to a point where I just could not listen to other 99 % of so called «normal» loudspeakers – which in comparison all sounded somewhat broken or wrong — unable to give any sort of ‘live’ feeling, missing the subtle inner details and dynamic contrasts.

WHT is a highly regarded line of designs.

To fully understand why WHT is so different we have the pleasure of having Mark tell us about the how and why of those speakers.

Mark is also a musician and his daughter Stella is a brilliant professional drummer performing in her own band Warpaint, as well as recording and performing with various highly regarded artists like Tom Jones (‘Spirit in the Room’), Flea (‘Helen Burns’), Jamie XX (live performances), Kurt Vile (‘Waking on a Pretty Daze’ & ‘Believe I’m Going Down’), Megan Washington (‘There, There’) and many more.




V: So Mark, I want you to be completely honest and not sugarcoat anything: why did you set out to make your own speakers and how your speaker design came to life also what is your No.1 priority?

Mark: I have been involved in speakers building from a very early age. First band PA speakers than instrument speakers and later studio monitors. I had my PA hire business for many years with the aim to provide the best possible sound quality.

The “so called” hi fi was basically continuation of what I did learn by building studio monitors and PA/ Instrument speakers.

My ultimate aim and priority is for the speaker to ideally reproduce the sound how it was recorded.  For me the reference is not a CD or LP purchased from the store, but ‘hands on’ involvement in actual recording and mastering session.


V: As I understand the slope is very special, it looks like a horn, what is it actually, how and why does it work, and how does it differ from a horn?

Mark: The original “J — BIN” or “SCOOP” has actually folded horn inside the enclosure and second half is reserved for the scoop.

All the scoop based speakers made by hi fi speaker manufactures are following this type of horn/ scoop design taking instructions direct from the available books like “Loudspeaker Enclosure Design and Construction” with includes folded horn being essential part of the Scoop design. In such cases, the folded horn is also acting as a filter cutting off frequencies above 150 Hz at the same time boosting all bass notes below 150 Hz as much as 4 dB up. The “unjustified” boost in a bass might only be very attractive to some audiophiles who are always bass hungry but not so much for someone who is expecting a linear performance. The problem is starting from E3 note and all above notes on the instrument scale which one will hear at much lower volume compared to the all the other lower notes. For example, your B2 and C3 notes will perform equally loud but the next E3 G3 will be heard like the string that was “accidently” covered with bitumen or in the best case honey ))).

It took some time to modify the design by eventually getting rid of the folded horn completely and extending the scoop to the full length of the enclosure. The closer description of the WHT modified J-BIN would be a “REFLECTOR”.

In this type of design a woofer is housed in the specially constructed front baffle while the scoop is the factor here helping to radiate full range frequencies from both sides of the diaphragm in a perfect phase.

WHT PR series is the only design allowing to take advantage of the complete woofer’s performance.

Nearly all speaker designs on the market will use typical baffle where the acoustic energy (sound) is produced by forward diaphragm movement. The back diaphragm movement is lost as the other half of the acoustic energy is hitting the inside of the box walls actually causing significant distortion.

Typical ported speaker will only have a port tube installed and it will be tuned for a slow release of low frequencies only.

Scoop’s speed can be tested in a very simple way which is by play string instrument through it and you know how accurate and super fast the sound is coming out on the speaker site. After building and trying all types of speakers I can say with confidence scoop is the fastest of all speaker designs.

Here is one statement which I fully support and agree with.

“What I can’t stand with bass reflex, ported or vented they boom unnatural booming and resonances which J-bins, Scoop bins W bins do not.”


V: Your PR loudspeakers look very elegant and with just two drivers, some might say they seem to cost a lot with so few components, but that is actually the secret isn’t it?  As I understand, you are able to use no crossover – just a capacitor to the tweeter.

Can you explain why this is so complex when it looks so easy, and why you have to make your own drivers?


There is number of factors which is related to the cost of making our speakers but we just don’t think about during the design process as any cost cutting would just compromise the final result. If you compare WHT speaker prices to the Made in Japan Feastrex woofers ( RRP from $7 K each woofer to $69 K for a single woofer ) you would probably agree that our speakers are relatively inexpensive. To me the array of 10 woofer and tweeters in a two or more enclosures per site does not justified the high price if the single components cost only $15 each. Speakers with many woofers of different sizes do need many passive complex crossovers in every section. The problem is that the crossovers are calculated based on test measurements: 1watt/ 1 meter/1 speaker.

Now please let me know as soon as you will spot even one audiophile who is sitting in the front of 1 speaker at the distance of 1 meter and the volume is set exactly to 1 watt only!!!

As silly as it sounds it is the way the so called “engineers” are designing speaker crossovers.

The reality is that every time you raise the volume with even 0.5 Watts increase the crossover doesn’t filter the same way it should. You would need to design another crossover for the higher volume. If the volume you are listening is let’s say 5 watts you would need to have 10 passive crossovers with the option of switching between them to be able to go up with the volume gradually.

No one from so called “industry” will tell you about the phase problems and loss of signal plus loss of harmonic structure crossovers will definitely be responsible for. Speaker manufactures will be happy to show you how complex their crossovers are but to me only means the components needed so much of additional electronic adjustment to achieve what can be done if they choose better quality woofers and matching components which is basically our way of making speakers.

In some cases there is as much parts as you could find in your microwave, most of them totally unnecessary.

Making own drivers is the only way to not only to take control of the speaker designing from the start to the end but also allowing us to progress and make further improvements.

I simply don’t believe that so called “custom made” woofers for a particular brand of speakers are very different to the other twenty or more “custom made” woofers made for many other speaker manufactures.

There is not a single case where the well know components manufactures would make woofer with 87 dB efficiency for one speaker brand and a 102 dB for another.

The day we did manage to construct woofer which would match a ribbon tweeter without the need for passive crossover was one of my happiest days ever. The very high quality capacitor before the ribbon tweeter is necessary for protection of any tweeter and ribbons need such protection even with the active crossovers in the signal path.

My dream speaker ideally would be the one with a single driver with no crossover doing all we want them to do.

Until today despite number of manufactures claiming that they have such product available, single full range driver doesn’t exist yet in my opinion.

Two high quality drivers are more than enough to cover the musical range especially if the ribbon driver is involved which can reach up to 100Khz.To me, the most important WHT achievement was to match the paper cone very efficient woofer with the super-efficient and accurate sandwich ribbon tweeter.  Again this would not be possible if we wouldn’t be able to make our own drivers.

V: I personally have had some issues with ribbon  tweeters; in most of them I can hear the “sound” like a slight ‘hiss’. However on your speakers I do not hear that, it is ultra clean but never hard — how do you do this and why do you use the drivers you do? I understand that you have tried the most regarded and expensive units on the market and would not use any of them?

Mark: For many years and for the same reason I couldn’t hear what the ribbons supposed to be great for. Good on the specs paper but when I listen to a number of speakers with ribbons tweeters I can heard similar problems and in most cases it was very hard to even tell what the ribbon should be covering.

At the same time I was a big fan of the ribbon microphones and constantly searching for similar sounding quality efficient tweeters.

Before more details how we’ve  found the perfect ribbon I would like to mention here another “popular choice” for high efficiency drivers.


As I know very well all compression high frequency tweeters and what is their role in a large complex P.A system. Speaker manufacturers which are employing PA woofers are more than happy to use compression drivers as their high frequency tweeters.

I could never imagine audiophiles to listen to such combo in the typical size room. Possibly without even realizing designers are creating two different systems (even in one package) which are simply impossible to level even with complex passive crossovers.

Typical PA 15“can be 96 dB efficient and the compression driver can reach very high efficiency 116 dB even 118 dB  ( 2440 JBL ) means 20 dB difference.

Normally the two components are design to work in a very large venues or outdoor concerts where the mixing console and most audience would be far from the speakers. 50 meters minimum to large venues where the mixing console is at 500 meter distance or even further than that.

The bass woofer will be heard at the very long distance but the high frequencies will struggle with every 100 meter distance dropping the volume or their efficiency. At 500 meters distance where the sound engineer is working on the final mix the woofer and the tweeter sounding more like a matched combo as the high frequencies can be heard but  with much lower efficiency.

The quality of the sound in such environment is really not important so much.

The tweeter needs to withstand serious abuse from screaming guitars and drums.

To bring the same components in to hi fi room and try to achieve linearity it is simply impossible. 20 dB difference between woofer and tweeter will be very much a problem no matter how many resistors are in the signal path trying to shut the screaming compression tweeter.

This is why I was always in a lookout for a high efficiency linear tweeter. We had for already success with a nice planar tweeters but the purity of the ribbon was always the perfect solution.

I did try all the available ribbon tweeters and even tried to build my own.

My experience with corrugated ribbon tweeters ended quickly because they will stretched no matter what and must to be replaced every few weeks.

Tweeters we are using now are pure ribbon tweeters but the aluminum foil is a sandwich type which finally is a very reliable unit.

Ribbon tweeters are so sensitive and so accurate they need to be use with a very minimal and the very best quality parts on the signal path. Complicated crossover used with ribbons can be heard more than the actual ribbon so I think you previous experience with ribbon’s “hiss” can be caused by crossover which works on paper only.

People tend to cut them around 5K or use them more like a super tweeter, while the new efficient ribbon drivers are able to cover  nearly upper midrange with incredible speed and very precisely extend to the super highs.


V: Let’s move to your IQM series: you no longer use the scoop, and I was actually a little more skeptical initially with those, because they look just like a normal box with drivers, but I like them very much, they are doing things a little different than the PR series (actually goes lower in the bas).

Why did you start with the IQM series and how did you make them sound so “unboxy”?

Mark: Here is what I should revealing the secret))

In the early days speaker designers didn’t use computers and need to listen more than today to achieve anything which would respond to recorded or performed music. Some of the woofers if not most were brilliantly constructed.

The fundamental difference between our process of making speakers and possibly all other manufactures is the fact that we do make the speaker box first and then we are trying to make suitable woofers for the particular speaker box. The others are making speaker exactly the opposite way. Or rather buying to woofers first and making the box later.


Lastly, as I mentioned, it is really hard to describe what your speakers are capable of, as a customer — why should I choose one of your speakers in this crowded market?



Please add some more questions if there is any issues that are not fitting in with these, this is just some questions that I would came up with as some of the first I would like to get explanation on.

And Mark- make the products first- then we take this JJJJJ.


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