Thanks for the invite

verdantaudio

New member
I am the founder and speaker designer at Verdant Audio and importer for Art Audio. I am retailing a variety of products to meet multiple needs including a broad line of Tubes. I was a 25 year audiophile who has increasingly become more involved in this hobby when I entered the business earlier this year with the launch of my products at AXPONA along with the re-introduction of Art Audio to the US Market.

I am a fan of any equipment that is easy to use and sounds good.

Anyone interested in composite cabinet speakers, elite tube gear or needs tubes should reach out. I will offer a forum discount to anyone.
 

kach22i

New member
I am the founder and speaker designer at Verdant Audio and importer for Art Audio. I am retailing a variety of products to meet multiple needs including a broad line of Tubes. I was a 25 year audiophile who has increasingly become more involved in this hobby when I entered the business earlier this year with the launch of my products at AXPONA along with the re-introduction of Art Audio to the US Market.

I am a fan of any equipment that is easy to use and sounds good.

Anyone interested in composite cabinet speakers, elite tube gear or needs tubes should reach out. I will offer a forum discount to anyone.
I went to your website, and read about rigid composites with superior damping properties as compared to MDF and wood.

No argument from me, but would like to hear about the development process of testing various materials and how the tone or lack of tone via damping came about.

For instance, what happened when you compared a very thin wall composite to a very thick wall composite?

Was there a magic middle thickness, and what was it doing right that the other extreemes were not.
 

verdantaudio

New member
So, testing went like this...

I built the same box based on interior volume and dimension via a series of materials; MDF, Baltic Birch, Fiberglass over Nomex and CF over Nomex and I had a cabinet produced using CF reinforced ABS. This was pricey so I did one of each. The only deviation is the thickness of the internal brace. The MDF and Wood cabinets had a 3/4" thick brace. Used the same crossover, same drivers attached to the same system. Each cabinet had 8ozs of polyfill measured on your typical kitchen food scale.

Pink noise showed no noteworthy difference. When listening, the CF over nomex was clear, Fiberglass & Phenolic was less clear, Balic Birch was less clear and MDF least clear. The CF reinforced ABS was so bad I think my wife asked if I had a sock taped over the tweeter. At $800 a cabinet unpainted...yikes.

Clarity was determined by my listening tests and my ability to observe details in a song vs. a highly regarded $1500 stand-mount that is not the Kef LS50. The song I used was "These are Days" from 10,000 maniacs. I took notes and compared notes. The MDF vs Baltic birch was similar. My simple and less than optimized design under-performed the stand-mount I had. The Fiberglass and CF cabinets outperformed. Then, the key was optimizing the design. I had an idea of how I wanted them to look and it was just a matter of getting the speaker volume right.

Ultimately, adjusting the crossover values in terms of the resistor for the tweeter and one of the capacitors increased detail and offsets the lack of damping from the less rigid cabinets. This unfortunately leads to an increase in brightness. One test I did not perform on those cabinets was a swap of fiberglass for the poylfill as it is suppose to be much more effective as a damping material but I am going to explore that when I introduce a bamboo speaker.

Regarding composite testing, that was not as extensive as I like it to be. I took the advice of the aerospace guys and in this case they told me that Nomex is superior to airex and balsa for damping and they have done extensive testing. They use it for the interior of planes and for multiple reasons they prefer Nomex. I was less concerned with the self extinguishing properties and more concerned with its ability to add rigidity and its incremental sound damping abilities. It is the most expensive of the typical pre-fab panels available.

I have recently been introduced to a material that is used for the interior damping of helicopters and they tell me they can reduce 120db to 72dB with a 1/3" panel. This is what I am exploring for my "statement" speaker. I am also considering a few other materials like quasi-isotropic panels which should be very similar to what Magico uses in their M line of speakers.

In aerospace, they use 1/4" panels for the most part. My feeling was if they could use these panels to dampen air and engine noise, it would work on a speaker. If you look at the thickness of most speakers, 1/4' is a very convenient thickness.

Regarding testing composite thicknesses, I did not. The thickness I opted for initial way outperformed MDF and Baltic Birch and was easy to mount speakers on. Thicker materials probably perform better but would create all sorts of challenges in terms of mounting the drivers and machining. Thinner materials might also perform just as well but I can't flush mount a speaker to them.

I wish "testing" was a sexier process using accelerometers or maybe playing 120 dB tone in a sealed box and measuring the sound 1M from it, etc... Reality is this is a startup that I am funding myself and if I fail, I will be working till I am 80, at least.
 

verdantaudio

New member
One other though, when I say outperformed or underperformed my reference stand mount, I am explicitly talking about observable details. I just rant this same test but in a much more precise way...sort of.

As a matter of curiosity, I built a pair of Nightshades using Blackthorn parts to create a sort of frankespeaker. The drivers, cabinets and crossover boards are identical in terms of size and the only difference between the Nightshade cabinet and Blackthorn cabinet is the composite used. I had the speakers professionally measured by Excelsior Audio prior to release. When you look at measurements like the burst decay, they are very similar between the two cabinets and showed less than 10% deviation in performance.

I honestly thought there would be a minimal difference to a point where I wasn't sure the incremental cost for the CF was worth it. Boy was I wrong! I really love the Blackthorns and short of the Kaiser Chiara's (which IMO is the best stand-mount in the world) they are my favorite speakers. Yes, I know I am biased but a part of that was I built a speaker exactly to my taste. And yes, I ran out-of-stock after AXPONA but that was more because I can't keep 20 units in inventory due to high cost. Anything to bring prices down is appealing in my mind. Enough context, on to the test.

Listened to "These are Days" several times immediately prior on Blackthorns to reacquaint myself with the details (my wife HATES this song now). Dropped the speakers ins, and my immediate reaction was shock. They sounded awful. In the frankenspeaker, prominent guitar notes virtually disappeared and the speaker was dark. You still new it was the same song and it was technically competent but that addictive level of nuance and the dynamic soundstage were gone.

In the initial development phase I worked on my own crossovers which to put it kindly, sucked. I hired an expert and needless to say his crossover designs were far superior. For the Blackthorn, I played with values a bit, but the initial, modeled crossover is virtually flawless. What is in the box was the original, modeled design. In the Nightshade, the initial sound was a hair dark. At the time I wrote this off to a bit of an error in the modeling. Couldn't expect every model to be perfect and I tweaked one of the caps in the tweeter and the resistor by one value and the speaker came to life but is not as neutral as the Blackthorn. Choice of the PX vs CSA cap enhances this slightly as well.

So I did the reverse and build a Blackthorn using Nightshade parts. Turns out, the speaker is bright and painful to listen too. Went back to the original crossover which I still had lying around and it sounds perfect.

The only deviation between the two is the composite skin. Now, take a material like MDF that isn't in the same league as fiberglass. You are not longer tweaking the cap and resistor one value to alleviate the darkness but you might need to move the cap 2 or 3 values. Not shocking at all why a lot of MDF based speaker lean to the forward/bright side of the audio spectrum and you don't get the level of detail that comes from a composite or aluminum cabinet.
 

kach22i

New member
Thank you for the run down, nothing beats human ears for testing in my opinion.

B&O RL (red lines) that I have I think are some kind of ABS plastic enclosure and that limits earth shattering volumes.

B&W Blue-Room speakers (snowmanish) were fiberglass when they first came out were amazing but the later switch to plastic ruined them.

Z-Plex allows 3D curves but I do not know of anyone using them for speakers, it is sponge foam like until vaccum bagging.


Any makers using mineral wool in lieu of fiberglass insulation?

I hear it has good sound damping properties.

Cheers, George
 
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verdantaudio

New member
There are so many cool materials available that can do great things. It is a shame more companies aren't willing to take a risk and use something other than MDF. If there was broader acceptance of these composite materials, consumers might start actually looking for them and seeing the benefit.

I have also been trying to figure out how I could make a cabinet using concrete board. The biggest challenge from my perspective is flush mounting the speakers as I am not sure the panels would stand up to the milling process.

I have not used mineral wool but may look into it. Interesting material. Done right, could radically improve performance of an ABS based speaker.
 
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