Nice. I am interested to see the I uncorrected curve, the correction curve and subwoofer curve (presumably you are using subwoofer)? What DSP setup are you using? What is the mic distance from speakers and how big are the speakers?
Actually, while we are on the topic of EQ, I’m thinking that using one of the current series of Pioneer or Onkyo home theatre systems with Dirac live is probably the easiest, cleanest way to build systems with active crossovers, sub crossovers and EQ. Anyone have experience of these? Sound quality would measure worse than hifi units, but I suspect you would not notice in a blind test, unless the noise level is high enough to hear (and with age-related hearing loss, probably not even noise would be a big concern).
Hi, not sure if you have seen this about DMLs. Convincing. If this was discussed, ignore.
DML Fantastic Speakers for less than..
DML Fantastic Speakers for less than..
How to reply to most recent (last) post:
You may have noticed that the 'quote' button is recently missing from the previous post (they may have added a timeout, or it may be a bug, idk).
I messaged the forum admins about it, but in the meantime, you can:
You may have noticed that the 'quote' button is recently missing from the previous post (they may have added a timeout, or it may be a bug, idk).
I messaged the forum admins about it, but in the meantime, you can:
- roll over the post serial number, look down at the address and remember its internal number (last sequence of digits) Eg this very post is 7253379.
- roll over the quote button for any other post, right-click, copy the address and paste into the address bar
- change the internal number to that of the latest post
- hit enter to give a new post with quoted text of the last post
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Yea, maybe its a safety feature in case the user decides to delete the post, or edit it. But if so, the timeout is seems too long. PS you didnt use the technique
My thought experiments usually start by extrapolating to the logical extremes...
On the one hand, will the driver itself produce decent HF when the VC is connected to a thin, stiff, light panel? Probably yes.
On the other hand, will it produce decent HF when connected to a soft, thick, heavy panel?
Probably no.
Then the third question is whether there's a sweet spot along that curve where all of the parameters work together 'just right' to produce HF that exceeds the first case. Maybe. But I don't know for sure and the manufacturers don't help, and I haven't spent enough time on this one.
My Eureka moment was when I eventually got frustrated with lack of HF and simply stuck all the different drivers onto CDs to compare their responses. And THAT was when I discovered the atrocious response of high-power, large (32mm VC) drivers compared to the smaller ones.
To be continued one day...
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I find, again, that this depends on the driver?
I was extremely disappointed with both HF and LF response from expensive, high power drivers, and especially so with the so-called "MegaBass" drivers.
Imagine my surprise when I applied a 20W cheap driver to the same panel, and suddenly discovered that I did not really need a sub any more!
I should fess up, I did the same with a cd case. Felt sure I would get some HF with the DAEX19-CT4 exciter. Nope. But if memory serves, not as bad as XPS.
Typical Ben channel on youtube got what seemed to be excessive HF with the dayton thruster on acrylic. Seems to be a resonance effect, but if that works....
Here's a 40W, 32mm VC DAEX32QMB-4 MegaBass driver,(red curve) around $22-00, compared to a 20W, 25mm VC DAEX25Q-4 (blue curve) at around $14-00.
The panel was a 5mm polycarb Twinwall panel (pic attached), 540 x 550 in size. I think that's one of the dimensional golden ratios for the most even distribution of modes. The panels were un-damped, supported top and bottom only on 5mm foam tape.
I have adjusted the relative levels to make bandwidth comparisons easier.
There's a significant peak at 15k on both drivers which is not there on EPS (with Kevlar skins) nor on anything else I've tried. I suspect the peak is due to the size of the corrugations in the Twinwall. I need to test this by filling in some of the channels around the driver with silicon, or glue. Or something.
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While some here had a moment of mirth (#9,030) over the poor soil and the small rocks, that actually reminded me of certain types of rocks which had been considered as the surface material, top and under surfaces, of the DM radiator panel. A certain types of rocks are actually used, as some DML manufacturers state, in their crushed form, to improve the acoustic qualities of the surface layer. Soil, after all, is produced by rocks, through the processes of weathering and natural erosion, its parent material.
By the way, Tim Whitwell, the inventor, whose work led to the creation of DML500 is a real life scientist and an engineer.
Head of Acoustics NXT >> Lead Technologist HiWave Technologies >> own company >> VP Engineering Tectonic Audio Labs from 2016 - present.
By the way, Tim Whitwell, the inventor, whose work led to the creation of DML500 is a real life scientist and an engineer.
Head of Acoustics NXT >> Lead Technologist HiWave Technologies >> own company >> VP Engineering Tectonic Audio Labs from 2016 - present.
Here's the ($26-00!) DAEX30HESF-4 on a CD. That's the CD disc itself with the 15mm hole in the middle...
The red curve is with the CD untouched.
The blue curve is with the hole sealed with hard, light plastic and superglue.
The hole causes a massive notch at 1.2khz.
But it seems there is something to be said for an improved HF above 10khz... This might be a result of a resonant cavity formed inside the voice coil, and then projected through the hole (exactly like the hole, which is carefully tuned, in an acoustic guitar) but which is completely suppressed when you stick a driver onto a normal panel without a hole (which is exactly what you do to prevent feedback on an acoustic guitar)
The normal application, on a normal panel without a hole, shows an obvious drop from around 9khz.
Things to try,
- Block the open ends of the twinwall corrugation with with some cotton wool and tape them shut,
- Add thin light damping material under the sheet on the perimeter 15-18% of the panel dimensions,
- Paste a thin alufoil disk between the exciter and the panel. The area within the bobbin should be free of anything.
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Yep... And tinnitus helps😁...oddly though, even though I'm HF compromised in frequency tests, I can hear the difference in music... I've read about this phenomenon before... It's something to do with harmonics
Eucy
I don't know how to do the quote thing.
Imagine an F-15 fighter plane parked 30 feet away with one of its engines idling, and you couldn't hear it because your tinnitus is the same frequency and harmonics and the same db in your head. That's how I got my tinnitus. How on earth could that help you enjoy listening to your music? That's my predicament. Your tinnitus may help you, but it definitely does not help me!
Eucy
I don't know how to do the quote thing.
Imagine an F-15 fighter plane parked 30 feet away with one of its engines idling, and you couldn't hear it because your tinnitus is the same frequency and harmonics and the same db in your head. That's how I got my tinnitus. How on earth could that help you enjoy listening to your music? That's my predicament. Your tinnitus may help you, but it definitely does not help me!
The AER bbx exciter reminds me of Toru Maruyama's single point conical transfer of vibrations to a panel, posts #7,115, #7,129
The point of contact here too is just a single point, the optimal transfer of vibrations.
The Aiyima exciter (below) can also be made to work as a single point vibration transferring emitter, by fixing a cone-like screw, a somewhat crude attempt, though.
Most of the NXT/Tectonic patents mention this point transfer of vibrations...
The point of contact here too is just a single point, the optimal transfer of vibrations.
The Aiyima exciter (below) can also be made to work as a single point vibration transferring emitter, by fixing a cone-like screw, a somewhat crude attempt, though.
Most of the NXT/Tectonic patents mention this point transfer of vibrations...
Before crossing the MMM (Moving Mic Measurement) method I was in the paradigm a mic as to be fixed for a measure. Not at all. You can have it at hand, move slowly over the area to cover. It works really well. Only point : take of possible noise with the cable. Have a look at my post on MMM or on the net, you will find the REW setup.
Christian
Sorry, I was being facetious, it's a trait in Australian humour often lost on an international audience.😃..(except the English👍)..
Tinnitus is definitely a curse, not a blessing, and mine's getting worse. Thankfully, I seem to be largely able to ignore it and get on with things...I was more referring to general hearing loss seeming to be partially at least compensated by some unknown factor in music... I'll have to do a Google... It's been years since I read about it
Eucy
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