Open Baffle Suggestions

[simon]

This is as good as place as anywhere to post this photo I s'pose.

It's only taken 7 years to get to this stage . Huge thanks to James for all his help and patience. They're based on the recipe for Nick's OBs with Supravox 285GMF bass helper and Alpair 12P. The plan is to use the Supravox with my Fostex 208s and T90As once I've built some MLTLs for the 12Ps. In the meantime I'm running the 12Ps in in the baffles - they're in the additional boards attached to the front as the 208s need a bigger hole and I can easily switch between them this way. These baffles are just rough jobs to get me going - they're in the man cave so aesthetics aren't important at this stage.

So how do they sound? Apparently the 12Ps need 800 hours to fully run in, and initially they have to be treated gently so I've only had them on low so far. And there's no crossover yet so both drivers are working between ~200Hz and 5kHz. And the Supravox is a fair bit more sensitive than the Alpairs.

To be honest I wasn't expecting too much but they're really rather good . Remarkably coherent and balanced, the bass sounds really clean, unsurprisingly. The Alpairs are sweet too. I really wanted to turn it up and let rip but managed to contain myself. Patience Simon. If they sound this good now I can't wait for them to run in, and then try the Fostexes.

[IslandPink]

Nice work !
Glad you're enjoying it. I'm messing about with a lot of half-finished stuff that is really musical too

[al newall]

That's good Simon.

So lucky to have a man cave.

I think it's interesting how easy it can be to get a good sound from baffles, and with a little effort they can be brilliant.

[Paul Barker]

Yes I agree on all points Al. It is just a shame it is hard to get enough out of baffles in most domestic shared environments. With the possible exception of quasar's. but at what cost?

I suppose bass is the problem. Less base smaller baffles would suit the environment. Hide a sub away in a corner.

compromise.

Or sit here moaning.

[pre65]

Well done Simon, glad you have got there at last.

I look forward to reading about how you make progress with them.

[simon]

Absolutely right Paul. Baffles need real estate and aren't generally domestically acceptable. There was no way I could even think about them in the old house, now I have somewhere to play. The boss can hear how good they are so there's a chance hey might make it downstairs, but the physical size is a real problem. All to play for!

[Cressy Snr]

Nice work Simon, you kept those quiet.
Is that a Loftin-White with posh output transformers I spy in the background or a 300B with d3a drivers?

[simon]

Right sort of area Steve - D3a-2A3 with AE c core OPTS. Comparing the size of the required real estate for GM70 or Madness there's a LOT to be said for the 2A3 amp.

[chris661]

It is possible to make reasonably small dipole systems.

http://linkwitzlab.com/LX521/Description.htm

Linkwitz uses lots of equilisation to get flat responses on tiny baffles, and a pair of long-throw 10" subwoofer drivers a side (presumably with quite a lot of amp power).

Alternatively, ripole LF systems might be worth a look.

Chris

[Scottmoose]

They are, but as above, you need power. Lots of it.

[chris661]

They are, but as above, you need power. Lots of it.

I'm not so sure: how much power will something like that take before the clanking noises start?
My guess, for one of these or similar
http://www.europe-audio.com/Product.asp?Product_ID=4296
would be <50w/ch.

That doesn't seem like a lot of power to me, but then again I like my big solid state amps.


If anyone's interested in ripole LF systems, there's a rather good diyAudio thread about them: http://www.diyaudio.com/forums/subwoofe ... -subs.html

Chris

[IslandPink]

I think me and Ray are more interested in getting results without digital equalisation and lots of SS power . I'm pretty certain it's going to sound nicer and more convincing that way .

[Ray P]

I think me and Ray are more interested in getting results without digital equalisation and lots of SS power . I'm pretty certain it's going to sound nicer and more convincing that way .

Yep, I've got the t shirt for lots of SS watts and not many dB speakers - seemed good at the time but ultimately disappointing.

I'm looking for a speaker project that a gnat could power.

Ray

[Scottmoose]

I'm not so sure: how much power will something like that take before the clanking noises start?
My guess, for one of these or similar
http://www.europe-audio.com/Product.asp?Product_ID=4296
would be <50w/ch.

That doesn't seem like a lot of power to me, but then again I like my big solid state amps.

It's not about how much power you can ram up the driver's jacksie before it waves the white flag, it's the fact that the conversion efficiency of ripoles is at best mediocre -often worse than standard baffles, U frames or similar. So if you want to go loud / have significant LF dynamic range, you need power. Or several of them. Don't get me wrong, they're a perfectly valid concept, done well, as Linkwitz & some others have, but power and often Eq are usually necessary, so if a high efficiency system is the goal, they don't leap to mind as a solution. Presumably exceptions exist somewhere along the line, but I haven't run across any yet.

[chris661]

Interesting. I'd've thought the increased path lengths would yield increased efficiency, and a fairly small footprint.

Reading to be done.

Chris

PS - while not necessarily the most convincing in terms of tiny details, my mains are ~98dB@1w, and have >200w/ch on tap. They can do dynamics like... Well, you can probably guess.
I'd be interested to hear them on the end of a fleawatt valve amp, though, to hear what I'm missing.