audio-talk

Nick wrote: ↑Fri Sep 10, 2021 10:08 am Useful info Mark. Basically my hope with these drivers is to work with them rather than trying to force them into submission. Time will tell.

In my mind you have summed getting the best out of any driver.
Too many people take the latter approach and as a result are not happy with what they end up achieving.
My experience is that a simple crossover is not an any easy thing, it takes alot of listening and measurement to get the best integration. And is near impossible without carefully matched drivers over the frequency range.

Went to Colin's last Saturday to play around with some speakers. Among other things, I took some measurements of the current iteration of these prototypes.

There's a bullet-style tweeter (Ciare? - Colin will know) running with a cap and an L-pad. We did some adjustments to the L-pad:


And also took some off-axis response curves:


The tweeter seems to do well at keeping the sound consistent in its coverage angle, but drops off quickly outside of that. The ~7kHz peak is courtesy of the Lowther.

Measurement distance was roughly 1m, so there's definitely some "room" coming in.


I think they're about as good as they'll get with this driver complement. I'd still like to try the Supravox with a good 1" compression driver, but that's getting away from the design brief.

Chris

PS - It's just occurred to me that the HF level being set by ear might be in response to the fairly narrow (and forward-only) directivity of the tweeter. The relatively (compared to at the listening position) close mic placement would mean mostly direct sound, whereas further back you hear more off the off-axis+reflections, which will have less HF content. Putting the mic at the listening position would've confirmed that - something to try next time.

Thanks for that Chris. As it happens I got an email today saying the acrylic bits are starting to be machined.

Mint, 801a is ready!

I’ve just happened upon a post by Nelson Pass re full range drivers. Seems he is also a fan of the PM6 Silver, albeit modified with Slagle Field Coils. Nice to have an upgrade path Nick

Well, there is a thing Ian. Happens Dave owes me a couple of flavors anyway

Time to balance the books?

Well, getting them working first would be the first step. Though I do have a a spare 8R pair of them I am not using at the moment.

iansr wrote: ↑Wed Apr 06, 2022 1:20 pm I’ve just happened upon a post by Nelson Pass re full range drivers. Seems he is also a fan of the PM6 Silver, albeit modified with Slagle Field Coils. Nice to have an upgrade path Nick

Nick wrote: ↑Wed Apr 06, 2022 1:43 pm Well, there is a thing Ian. Happens Dave owes me a couple of flavors anyway

Nick wrote: ↑Wed Apr 06, 2022 3:13 pm Well, getting them working first would be the first step. Though I do have a a spare 8R pair of them I am not using at the moment.

Now this could be an very interesting development/experiment if Mr Slagle modifies your 8 ohm PM6's.

Now this could be an very interesting development/experiment

Well, I have been musing how well they would work in combination with a pair of these

https://en.toutlehautparleur.com/open-b ... -inch.html

This brings to question, could the acrylic baffles currently under manufacture be easily modified to accept the 15" SB bass driver to replace the smaller Supravox to which they are currently being made for? Certainly would be an interesting combination. I do confess to liking SB Acoustic drivers and SB Audience are the PA/Commercial speaker arm of SB Acoustics, I believe.

Likely we would have to build a new set of test mdf or chipboard baffles to prove the concept pairing and be able to do a direct A-B comparison to the standard 4-ohm silver PM6 with the Supravov. Should keep us busy for while! Might need Lynn's blessing though for me to knock together a new set of test baffles. But I'm sure she will come around to agreeing.

EDIT.
Checking out the published FR plot I think the quoted manufacture sensitivity of 98dB for 2.83 V / 1 m may be little optimistic and more likely the calculated sensitivity of 93.63 dB is more realistic. So may not have the sensitivity to match the PM6 silvers? Just a thought. Might be worth awaiting until someone does a full review with actual measurements of the 15" SB divers before committing to buying.

You might want to hold fire; I have it from the horses mouth that SBA are going to be bringing out some 18” Bianco woofers for OB . . . .

It was all just musing at this point

Those 15's do look good actually, nicely judged. Would go a bit lower than the 285's. The treble lift looks quite well controlled compared to many other bigger drivers.

The Quasars would need to be redesigned to take advantage of tbe SB 15 inchers... And would end up bigger.... Ideally wider, deeper and taller...

But the main problem would be tbe poorer tone from the SBs compared with the Supravox unless you crossover below about 100Hz the tone difference between the PM6s and the SBs would jar...

If you want a 15 inch driver I would go for the new Supravox 380...

James