I have been designing another small MEH.
So far I have been designing it around the Faital Pro 2fe24 however from doing measurements the distortion is mega high at 10% THD at 10W around 600hz. It's still mega high on less power minimum 2% or 3% THD
Edit: thought I would add that this distortion is even just with a small rear chamber and no front chamber/ports/horn
This is the rear chamber I made for it: (I got the 3d file from Faital Pro and seal it with a small o ring at the top)
It is fully sealed, you can tell because the cone is harder to move than when it's free.
I'm going to borrow some peerless 830970 to try which look a bit more suitable
Does anyone know of any other good drivers that could be used in a MEH that are 2" or 2.5"?
I'm trying to push the mid up to 2.5khz at least so I need a 2" really
So far I have been designing it around the Faital Pro 2fe24 however from doing measurements the distortion is mega high at 10% THD at 10W around 600hz. It's still mega high on less power minimum 2% or 3% THD
Edit: thought I would add that this distortion is even just with a small rear chamber and no front chamber/ports/horn
This is the rear chamber I made for it: (I got the 3d file from Faital Pro and seal it with a small o ring at the top)
It is fully sealed, you can tell because the cone is harder to move than when it's free.
I'm going to borrow some peerless 830970 to try which look a bit more suitable
Does anyone know of any other good drivers that could be used in a MEH that are 2" or 2.5"?
I'm trying to push the mid up to 2.5khz at least so I need a 2" really
Last edited:
the problem you are facing is that 2" drivers are inefficient to begin with, have small Xmax, and can't handle a lot of power. What can you do? use 4 of them; use the largest driver you can fit even if it means paying more for a CD that supports a lower XO, highpass cross them above the frequency where the waveguide loses pattern control and therefore doesn't provide any gain.
The DMA series of drivers from Dayton Audio are worth looking at. There are a range of size options from 1.5" up to 4".
The DMA series of drivers from Dayton Audio are worth looking at. There are a range of size options from 1.5" up to 4".
I will take a look at those. I am planning on using quite a few 2" drivers to get over the efficiency. It's more the very high THD even at low power
https://feleppa.com.au/speakermeasmid.html
Wavecor and Vifa may also have some good compact small mids.
https://www.wavecor.com/html/fr055wa01_02.html
https://hificompass.com/en/speakers/measurements/vifa/vifa-tc6fc00-04
Wavecor and Vifa may also have some good compact small mids.
https://www.wavecor.com/html/fr055wa01_02.html
https://hificompass.com/en/speakers/measurements/vifa/vifa-tc6fc00-04
Have you measured or calculated the Fb?
I tried a bunch of different small drivers and never found a 2-inch I was that happy with. At 2.5 inches, the ND64 and ND65 from Dayton were both good. They go down to around 400 Hz pretty cleanly, and will play lower if you accept rising distortion with decreasing frequency. I think the ND64 is being discontinued though, since it's listed as "clearance" at Parts Express.
The SB Acoustics SB65WBAC25-4 is another that does pretty well.
I was using them in sealed enclosures mostly, and don't have any experience with them in horns.
JBL has the 216x drivers for their professional line arrays, basically MEH.
They are low distortion (subject of several articles in the Journal of the AES), not aimed at DIY but available as replacement drivers at not exactly cheap prices.
The 2163 is the 3" version. Smallest they make IIRC but should do what you want.
Best wishes
David
That is a bit too expensive for my application. I need quite a few of them.
Thanks for the suggestions. I have ordered a Faital Pro 2FE2, it has the lowest Qts and BL of all the drivers I have looked at.
When it arrives I will measure it and post the results.
I will measure that today
The ND64 looks like it would be a good fit as well. It is twice the price of the Faital Pro driver though.
I am tempted to order one of those as well to test
I have designed a rear chamber for the 2ndf22
I'm going to print a piece to test the fitment then I will get it fully printed and measured.
I have a slot in the top for an o ring to seal it
Unfortunately the dust cap is slightly different on the 2fe22 than the 2fe24 and the model isn't quite correct so I will need to make some adjustments to the MEH design
I'm going to print a piece to test the fitment then I will get it fully printed and measured.
I have a slot in the top for an o ring to seal it
Unfortunately the dust cap is slightly different on the 2fe22 than the 2fe24 and the model isn't quite correct so I will need to make some adjustments to the MEH design
Attachments
Maybe try the Kartesian Wib50 or Wib70 for small fullranges with a fair amount of truly linear excursion
https://en.toutlehautparleur.com/fullrange-speaker-kartesian-wib70-vhp-8-ohm-70-x-70-mm.html
https://en.toutlehautparleur.com/fullrange-speaker-kartesian-wib70-vhp-8-ohm-70-x-70-mm.html
I would suspect I had done something wrong or that there was something wrong with the driver, if I saw very high THD even at low power. Back in the day, I built line arrays using 32 2.5" drivers each side and they showed the reverse problem - low THD at low power, high THD at high power but that turned out to be an inadequately braced rear panel. The drivers were the SB65WAC25. Lots of line arrays have been built using "quite a few" small full range drivers with good results.
I'm back to wondering what the Fb is for a chamber that small. In your model it looks miniscule. If we assume 0.02 liter sealed, you get an Fb of about 630 Hz if my sim is correct. I don't think you've specifically stated your lower cross point goals.
The Voice Coil review showed pretty high distortion at the typical test levels also. Since the sensitivity of the driver is stated as 85 dB, 94 dB isn't an extreme level to test at (but not "low power" either). The free air configuration for the test makes things harder to decipher, but the distortion plot would inspire me to test that aspect pretty early if I were investigating that driver.
https://audioxpress.com/article/faitalpro-2fe24-pro-sound-2-5-full-range
"For the distortion measurement, I mounted the FaitalPRO 2.5” full-range driver in free-air, and set the SPL to 94dB at 1m (7.2V), using a noise stimulus. I then measured the distortion with the microphone placed 10cm from the dust cap."
Last edited:
I have been using 0.02L in my simulations. I have been aiming for around there, I haven't measured the impedance yet to figure that out.
That graph is interesting, distortion looks pretty high on that driver in general. I will hopefully get some measurements of the 2fe22 tomorrow.
I checked some measurements I took around a year ago using the same driver and it had high distortion. They also had a different small rear chamber that I made using tape and hot glue.
That graph is interesting, distortion looks pretty high on that driver in general. I will hopefully get some measurements of the 2fe22 tomorrow.
I checked some measurements I took around a year ago using the same driver and it had high distortion. They also had a different small rear chamber that I made using tape and hot glue.
That aspect of their testing varies in how it is plotted, what the level is, and whether a test box is used or not. That makes interpreting the plots a little harder. I looked around a bit for comparable drivers tested the same way and included a few below.
With a driver this small running free air, dipole cancellation is happening so high in frequency that I can imagine it causing accuracy issues even at lower midrange frequencies. I haven't run a distortion test this exact way, so can't say for certain what the impact is though or what conditions interact.
https://audioxpress.com/article/tes...r070wa05-aluminum-cone-full-range-2-75-driver
"For the distortion measurement, I mounted the FR070WA05 driver rigidly in free-air and set the SPL to 90dB at 1m (7.66V) using a noise stimulus. Then, I measured the distortion with the microphone placed 10cm from the dust cap."
https://audioxpress.com/article/test-bench-wavecor-s-fr4x6wa01-oval-full-range-driver
"For the distortion measurement, the Wavecor 1.75” × 2.5” oval full-range driver was mounted rigidly in free-air, and the SPL set to 90dB at 1m (6.0V), using a noise stimulus. Then, I measured the distortion with the microphone placed 10cm from the dust cap."
https://audioxpress.com/article/test-bench-the-dayton-audio-dma58-4-2-full-range-speaker-driver
"For the distortion measurement, the DMA58-4 was mounted rigidly in free-air, and the SPL set to 94 dB at 1 m (9.86 V), using a pink noise stimulus. The distortion was measured with the microphone placed 10 cm from the dust cap."
https://audioxpress.com/article/test-bench-the-dayton-audio-dma80-4-3-full-range-driver
"For the distortion measurement, I mounted the DMA80 rigidly in free-air and used a pink noise stimulus to set the SPL to 94 dB at 1 m (7.55V). Then, I measured the distortion with the microphone placed 10 cm from the dust cap."
https://audioxpress.com/article/tes...phany-pmt-40n25al01-04-mini-full-range-driver
"to measure distortion and generate time-frequency PMT-40N25AL01-04 in free air, and used a noise stimulus to set the SPL to 94 dB at 1 m (8.1 V). I measured the distortion with the microphone placed 10 cm from the dust cap."
https://audioxpress.com/article/test-bench-scan-speak-5f-8422t01-2-full-range-driver
"For the distortion measurement, I rigidly mounted the 5F/8822T01 in free-air and used a noise stimulus to set the SPL to 94 dB at 1 m (7.2 V). Next, I measured the distortion with the microphone placed 10 cm from the dust cap."
https://audioxpress.com/article/Test-Bench-SB-Acoustics-SB65WBAC25-4-2-5-full-range-driver
"For the distortion measurement, I rigidly mounted the SB65WBAC25-4 in free air and used a noise stimulus to set the SPL to 94 dB at 1 m (7.2 V). Then, I measured the distortion with the microphone placed 10 cm from the dust cap."
Attachments
Well, it's not as bad as the 2164 (around $400 in Australia)😆
Or the 2165 (never seen a recommended price, probably have a non-disclosure clause and your first born child as deposit, but would be similar to the 2168, about $600 Australian)
Lucky I have started to boycott US products until they remove their tariffs on our products, it has saved me the need to decide if they are worth it.😉
The upside is that you don't need to "buy a bunch", unless you plan a system to play stadiums and arenas, that is what it's built for, should only need very few for domestic or any reasonable venue.
As mentioned above, you should be able to use fewer than a less "pro" driver, but yeah, not cheap.
They are available sometimes at more reasonable prices used, pulled from tour systems, I assume the cabinets may be end-of-life while the speakers themselves are still ok.
Best wishes
David
What is the objective, just for isolation?
I believe there is a school of opinion that it helps the top end, but as far as I can see, that is mistaken.
So I have always wondered what was the rationale.
Best wishes
David
It raises sensitivity near the low freq cut off. Look up reactance annulling.