audio-talk

Toppsy wrote: ↑Thu Mar 12, 2020 5:59 pm
With respect Steve I think you need to get out more and move on from the sounds and designs of the 1940's. Speaker design and electronics and amplifier design has moved on quantum leaps since that golden age period you seem to be stuck in. Ok if this floats your boat but it is your view which is not that of the majority of music lovers and DIY'ers or those who wish to design and sell a product that perhaps pushes the boundaries.

I know you have a lot of money and interest invested in vintage gear but things have moved on, sadly not you it seems.

I’m perfectly happy in the ’60s and love my Fanes, and the SME/Lenco with cheapo Goldring cart and 70s technology Class B, NVA amp. Have never been happier with my music. That’s what counts. Life’s too short for disagreements about the presentation.

Nick wrote: ↑Thu Mar 12, 2020 6:35 pm

I'm not sure you really need to be so blunt Colin, we are all friends after all ?

TBH, I would hope that as friends we should be just fine with being blunt to each other, life if too short IMHO to not say what we think. I would prefer to know that my friends can be friends even if we don't agree about everything.

That's very true Nick.. and both nice and realistic comments in your earlier post too
cheers..

Colin I'm quite happy to debate my views .. but in my opinion you miss read my post and over reacted.
Its not a problem...
Cheers

Well, that was a lively interlude!


No progress on the Lii speaker project this week, just too much on at work currently. Yesterday we had a film crew on the floorplate and I think I might have had my Andy Warhol moment!

Ye gods lads...

Different strokes for different folks. Since I design both single-driver & multiway speakers, I'm relatively neutral on the subject inasmuch as I think the best policy is to be aware of what is involved as far as possible, and use what best suits your preferences.

Be that as it may, regarding vent positioning, close to the driver provides more or less maximum efficiency; whether you actually want maximum efficiency is another matter. Usually not: most of the time it can come with a price. Given the dimensions, I'd be more inclined to locate it either at or as close to the base as possible, on an odd harmonic; say 4/5 length or just over.

FWIW anyway.

Now Colin is getting on with building some Quasar OBs for Nick's Lii Audio 10in drive units I guess I'll have to make use of mine at some point. Might still go with the Pass SLOB design but the Quasar is so well regarded...

Any thoughts on these units as bass helper for the Lii units? They were used by Troels Gravesen in his OBL-15 project, which I guess says something positive about them?

http://www.troelsgravesen.dk/OBL-15/15PR400.pdf

They're obviously larger that the Supravox 285GMF units.

I've seen his OB project , and these units are used with a passive shelf filter to even up the response, because it rolls off due to the relatively low Qts of the drivers. They are 800W power handling ( or 400 ) and quite high Rms ( 3.1 ) relative to the Supravox and EmBeta 15's whicha re below 1.0. Troels is known for playing loud. If all this fits your expectations, then don't let me stop you.

I ended up with the Supravox's after Bert Doppenberg's design of the Quasar Mk.1. and his work to find a bass helper for the AERs. I was looking for something to match the AERs after hearing them in a horn design and liking the sound of them but not liking the back horn design...

I not found anything since that matches the Supravox's tone and transient response in a passive OB bass helper role - and I have looked and tried a few over the years... but they are not cheap - the new GMF380 looks even better but its twice the price...

The Beta 15 is the economical choice and does everything well in this role without any omissions but it doesn't have the tone or sense of speed of the Supravox's. The Alpha 15 is not as good in this role although it has its own supporters and is often recommended due to its higher Qts.

BTW I find a Qts of 0.35 to 0.45 works best in this role rather than the conventional recommendation of Qts=0.7 for an OB... this is due to the Quasar loading the back of the driver more than a straight open baffle does... and its also down to my preference for a system Q of 0.5 or so - YMMV

GMF380 ... homework required !

Thanks for the steer guys, I'll look elsewhere then.

380 GMF units do look promising, but around £1500 for a pair...