Very nice, congrats! 🙂
Is there a reason for the horizontal gaps between the baffles? (I know PAP are similar, but would assume they leak sound and thus increase cancelation?)
Is there a reason for the horizontal gaps between the baffles? (I know PAP are similar, but would assume they leak sound and thus increase cancelation?)
Thanks fellas, glad you like it 🙂
Sound impressions - now, this is just a new cloth for the trial speakers, but new parts for the xo, so the basic characteristic is the same as it was at the end of the endless trials, but somewhat more refined. Very open and very clear sound with big (in fact, biiiiiiiiig) stage, great spatiality, superb location of the instruments with a very coherent sound at the same time. Crisp highs, goosebump mids - and yes, powerful bass, even if there is no kick into the stomach🙂
The gaps... I think around December I splitted one of the big one piece baffles because I wanted to try a different driver configuration (D'Appolito), but I didn't like the sound... So I mounted the now 3 baffles in the old (and current) configuration, while the other baffle was still one piece, and made a comparison... the result was that (in my ears) the one with the separated baffles and a gap of about 5 mm sounded cleaner, with more definition. Surprise 🙂 Out of curiosity I increased and decreased the gap, and noticed a significant quality loss above 6-7 mm, while decreasing of the gap had no effect (in my ears). I can only think that with the multi-part baffle the resonances are not passed on and thus the baffles and the drivers have less effect on the others. But this is of course far from a scientific conclusion 😀
Sound impressions - now, this is just a new cloth for the trial speakers, but new parts for the xo, so the basic characteristic is the same as it was at the end of the endless trials, but somewhat more refined. Very open and very clear sound with big (in fact, biiiiiiiiig) stage, great spatiality, superb location of the instruments with a very coherent sound at the same time. Crisp highs, goosebump mids - and yes, powerful bass, even if there is no kick into the stomach🙂
The gaps... I think around December I splitted one of the big one piece baffles because I wanted to try a different driver configuration (D'Appolito), but I didn't like the sound... So I mounted the now 3 baffles in the old (and current) configuration, while the other baffle was still one piece, and made a comparison... the result was that (in my ears) the one with the separated baffles and a gap of about 5 mm sounded cleaner, with more definition. Surprise 🙂 Out of curiosity I increased and decreased the gap, and noticed a significant quality loss above 6-7 mm, while decreasing of the gap had no effect (in my ears). I can only think that with the multi-part baffle the resonances are not passed on and thus the baffles and the drivers have less effect on the others. But this is of course far from a scientific conclusion 😀
What FR range driver did you decide was the best sounding? The photo of that top driver is only partial, I can't see which it is. Also, baffle board dimensions and tilt-back angle (if any)?
Hi,
I had to replace the SB Acoustics FR by the Alpair 12P, because one of the SB's has a strong mechanical noise/distortion... Sadly, it's currently not available here in Europe...
The A12P has over 150 hours break-in time now and it sounds better and better - and it of course sounds different than the SB (no, I still don't know which one is better 😀 ).
Today I made some measurements, like frequency response, impulse and waterfall.
The fr response looks good to me, it's tilted to the right - however, there is a through around 10 kHz, maybe a room issue (I have some high frequency echoes) and maybe a driver issue too, the A12P is somewhat uneven in this region. But - I don't care much, this is a region for people with 20-30 years of age, not 50+
So I like very much what I hear.
The impulse response is - I think - not that bad, but please correct me.
And the waterfall... honestly, I can't interpret it
Here a picture with the new driver and the graphs 🖖
I had to replace the SB Acoustics FR by the Alpair 12P, because one of the SB's has a strong mechanical noise/distortion... Sadly, it's currently not available here in Europe...
The A12P has over 150 hours break-in time now and it sounds better and better - and it of course sounds different than the SB (no, I still don't know which one is better 😀 ).
Today I made some measurements, like frequency response, impulse and waterfall.
The fr response looks good to me, it's tilted to the right - however, there is a through around 10 kHz, maybe a room issue (I have some high frequency echoes) and maybe a driver issue too, the A12P is somewhat uneven in this region. But - I don't care much, this is a region for people with 20-30 years of age, not 50+
So I like very much what I hear.The impulse response is - I think - not that bad, but please correct me.
And the waterfall... honestly, I can't interpret it
Here a picture with the new driver and the graphs 🖖
Moving to DSP with separate amps for each driver is quite different than what you’ve accomplished but may be worth a look. I currently have the MarkAudio 12P running full range in a MTM and enjoy them but have begun gathering parts to assemble an active 3 way using the driver’s from a passive open baffle system. Very much enjoying reading about your journey. I really like the brackets you used.
Cat approved
It seems there are no further design changes required, so here the baffle sizes, made of 19 mm MDF:
15" woofer 550 X 450 mm
12" woofer 550 X 345 mm
FR 550 X 240 mm.
The baffle is tilted in about 5 degrees, with more or less tilt the amount of the bass is slightly adjustible.
There is a 150 mm wing on both sides along the woofers.
That's it 🙂
But... the journey is not finished...
I'm thinking about to keep the design, but will go if not all-in but "much-more-in" 😀
So I'm searching for new woofers and FR, I'm curious how much better drivers can sound.
It seems there are no further design changes required, so here the baffle sizes, made of 19 mm MDF:
15" woofer 550 X 450 mm
12" woofer 550 X 345 mm
FR 550 X 240 mm.
The baffle is tilted in about 5 degrees, with more or less tilt the amount of the bass is slightly adjustible.
There is a 150 mm wing on both sides along the woofers.
That's it 🙂
But... the journey is not finished...
I'm thinking about to keep the design, but will go if not all-in but "much-more-in" 😀
So I'm searching for new woofers and FR, I'm curious how much better drivers can sound.
What is the difference between alpair 12p and alpair 12pw? Can I use the 12pw has FR for similar OB project or will it need a tweeter?
Hi,
the SB FR is available again, so I ordered a replacement for the "damaged" one and it arrived today.
Alpair-baffles removed, SB-baffles mounted with the new driver - and I think I like the SB more.
It has - for me - crisper highs and a more open midrange, the Alpair is somewhat dull in a direct comparison.
Next planned step: change the xo in order to get all three driver in phase, without connecting the FR inverted.
Fun, fun, fun 😀
the SB FR is available again, so I ordered a replacement for the "damaged" one and it arrived today.
Alpair-baffles removed, SB-baffles mounted with the new driver - and I think I like the SB more.
It has - for me - crisper highs and a more open midrange, the Alpair is somewhat dull in a direct comparison.
Next planned step: change the xo in order to get all three driver in phase, without connecting the FR inverted.
Fun, fun, fun 😀
It's the "new" SB Acoustics SB20FRPC30-8.
I wrote earlier that one of the driver is "damaged", and yesterday I replaced it with a new one. Well, it wasn't the driver 😛
I have some resonances coming from the driver when it will be loud, at some lower frequencies. I don't know yet if the paper cone will be "stimulated" by the woofers, or is it a resonances of the baffle, or room mode... funny, because I have it only in one speaker. And I had no resonance issue with the Alpair 12P. Today I will swap the speakers (right to the left, left to the right) and check if it caused by a room issue/mode.
That's not that much fun, however
I wrote earlier that one of the driver is "damaged", and yesterday I replaced it with a new one. Well, it wasn't the driver 😛
I have some resonances coming from the driver when it will be loud, at some lower frequencies. I don't know yet if the paper cone will be "stimulated" by the woofers, or is it a resonances of the baffle, or room mode... funny, because I have it only in one speaker. And I had no resonance issue with the Alpair 12P. Today I will swap the speakers (right to the left, left to the right) and check if it caused by a room issue/mode.
That's not that much fun, however
Troubleshooting tough problems can raise my blood pressure and frustration level, sometimes making wrong inferences. Try to slow down and keep cool, maybe take notes - it might help your logical reasoning process (it works for me usually)>. Good luck!!!