That’s a new one on me!
I bought some old speakers from a car boot for next to nothing because I could see the intriguing Pioneer branded magnet covers through holes in the rear.
Have you tried them to see if the tweeter panels are working or have I looked at the wrong drivers. Do you have the electrostatic ones?
I got one down this week and gently fired it up. All the elements were playing. The normal application seems to be a 20-30L vented box which is probably what I should do with them. Still haven’t quite got my head around how the hf panels work! They aren’t energised in the way a Quad or Shackman panel needs to be.
Electret a la cheapo Stax phones?
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That is exactly what I was wondering.
Was looking at my B&W DM70s today and wondering if AudioGold would like them.
Crimes against mounting bolt orientation 
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Not so. I couldn’t and didn’t want to interfere with the 4 existing Lowther unit mounting holes (& inserts) slightly different pcd too, so rotated each of the new drivers slightly and marked out & drilled 8 new pilot holes for my blingy screws.
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I may have a hoarding problem, on top of the remaining pair of Goodmans Axiom 201s I currently have, thanks to Steve57 I now have added a few more drivers to work through!
That’s 6x Axiom 301s and 4x Audiom 81 ‘Bass’ drivers. The 301s are the same as the 201s, apart from they have a larger/stronger magnet so much lower Qts. The 201s are around 0.6 so only really suited to closed/aperiodic enclosures where the 301s are designed for ported but are generally said to be better over the wider frequency range as well.
I need to work my way though the 301s, two at least need a little attention and one pair are a good match so I’ll stick those in the 201 cabinets and do some measurements between the 201/301.
I’ll likely sell the remaining pair of 201s, and probably a pair of 301s once I’ve cleaned and matched them up.
301 Matched Pair
201 Matched Pair
Audiom 81 Bass
The Audiom 81 ‘Bass’ are the low Qts/low FS hifi version of their standard pro/pa speakers. From new, I believe they have a very low Qts of around 0.25 and ~25Hz resonant frequency. They neatly form two somewhat matched pairs, one with higher fs and lower Qts, the other with well matched fs and little higher Qts (lower impedance and higher sensitivity)
1st Pair
2nd Pair
Volt BM2500.4
On top of that, I also picked up another pair of Volt BM2500.4 based speakers (a Wilmslow Audio SM110 kit missing tweeters) which would make (I think) a good match with the Seos12 horn and a BMS 4524 tweeter I already have. Very nice matching between the two drivers. I really liked the mid-bass punch on these drivers when I used the 4x older versions last year.
I do like the look of the Volt VM527 2" mid-dome but they are a bit spendy.
So quite an inventory right now, not 100% sure what to do with it all…
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Possibly something like this with two Audiom 15s, Volt 10" and horn…
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Nope. You really want a 100db driver. Why have a big system running horns if you throw all that sensitivity away down to 90db to match the volt.
B&c and the like have far more suitable options.
Another option is to buy a 2nd Supravox 165GMF to make up the pair and use that. I’d have done that but since Brexit the price has gone up, even buying through the new UK distributor.
The 165GMF is ~96dB so a good match for either of the two Fountek Ribbons, would require the Audiom 81s to probably play a bit higher.
First working development, a 1st order BW on the BM25004 to match 4th order BW on the 4524, both at 1.7kHz seem to give a nice response. The 4524 has a low Q (5kHz/-6dB/0.5Q) low shelf to flatten the horn response and overall has a nice downwards trend in room. Driver measurements taken at baffle distance on axis of both drivers.
I need to take them outside when I have some free time to set all the equipment up to get a clean 1m measurement and fine tuning, subjectively it sounds nice although a little thin in the midrange (on vocals) which does show up with a dip in the 400Hz-800Hz range in the close plot as well as the seated position,
In this room, I have a very large peak at 32Hz, showing here even after a -16dB peak in PEQ to bring it down.
I do have a noise problem from the mains that shows up on the ~109dB 4524 but not on the BM25004 (or Goodmans Axiom ~92-97dB drivers) so I might try reducing the output with an L-Pad directly (around 9dB) to start with and see if that helps. The noise shows up on these tweeters connected to multiple amplifiers with and without the MiniDSP so its not something equipment specific but a ground loop or something else in the house that I’ve not found as yet!
Modelling on the Goodmans Audiom units, 90L Sealed using Pair Two (well matched Lower Fs, higher Qts) and compound of one from each pair in a 120 Sealed. Qtc of ~0.7 on both. When compound it leaves plenty of headroom and capacity for EQ on the low bass for a somewhat modest cabinet size.
And progress so far on the Mid-Bass to Treble crossover:
Individual driver responses and at seating position response.
I am hoping having the two 15’s coser to the floor will help smooth out the bass response, negating some of the floor bounce issues.
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