Greets!
Yeah, the 1044s measured ~1.43 and the 1272 ~2.45! on a P.E. woofer tester.
That said, for an area where looks don't matter and the bass need not be room rattling to please and there's a couple of corners available, David Weems (audio's quintessential 'frugalphile') published some 'one size fits all' single fold labyrinth (now usually referred to either as an end loaded 1/4 WL pipe or TL) designs for different frame size drivers back in the mid '50s issues of Popular Electronics for drivers normally considered unusable in a HIFI app, i.e. high Fs/high Q small console or car audio drivers.
He made them from the then new Celotex 1/2" thick insulation board (~$2.50 for a 4 x 8 ft sheet at the time), an extremely well damped/lossy material, which combined with no additional bracing makes them ideal for super high Q systems. He used a CSA = 1.4*Sd for the first half of the pathlength, 'stepping up' at the fold to ~1.65*Sd for the other half, but we know today that 'bigger is better', so make it as large as practical with a pathlength = ~72" so that when combined with the corner it will give fairly broadband LF damping (relatively speaking) and if the driver's Fs is low enough to make it 'boom', then an aperiodic vent can be added to tame it.
We have many more material choices today though, so let your imagination run amuck like one poster did awhile back.
He mounted the driver on a typical box width OB, then covered it/boxed it in with styrofoam? insulation sheeting for a free standing speaker.
GM
Yeah, the 1044s measured ~1.43 and the 1272 ~2.45! on a P.E. woofer tester.
That said, for an area where looks don't matter and the bass need not be room rattling to please and there's a couple of corners available, David Weems (audio's quintessential 'frugalphile') published some 'one size fits all' single fold labyrinth (now usually referred to either as an end loaded 1/4 WL pipe or TL) designs for different frame size drivers back in the mid '50s issues of Popular Electronics for drivers normally considered unusable in a HIFI app, i.e. high Fs/high Q small console or car audio drivers.
He made them from the then new Celotex 1/2" thick insulation board (~$2.50 for a 4 x 8 ft sheet at the time), an extremely well damped/lossy material, which combined with no additional bracing makes them ideal for super high Q systems. He used a CSA = 1.4*Sd for the first half of the pathlength, 'stepping up' at the fold to ~1.65*Sd for the other half, but we know today that 'bigger is better', so make it as large as practical with a pathlength = ~72" so that when combined with the corner it will give fairly broadband LF damping (relatively speaking) and if the driver's Fs is low enough to make it 'boom', then an aperiodic vent can be added to tame it.
We have many more material choices today though, so let your imagination run amuck like one poster did awhile back.
He mounted the driver on a typical box width OB, then covered it/boxed it in with styrofoam? insulation sheeting for a free standing speaker.GM
Hi guys, it's been awhile!
My local Menards (upper midwestern big crappy building supply store) just started carrying 4x8 sheets of 3/4" Baltic Birch for $60. I was about to buy four sheets a build up some BIB's for my hemps. Then I got a gig working around 80 hours a week for a campaign. The good news is, come November, I'll be unemployed and have some $$ for plywood. In the mean time, the hemps sound awfully good as is.
Back in the neighborhood of page 22, GM conjurred a ML BIB for the Ascendant Audio Assassin 10 sub (double the CSA of the orignal TC design, but with an 8x8" vent). I can't remember where I put the chart he sent me, but I think it's worth inclusion in the BIB bass horn page, as the work is already done.
Paul
My local Menards (upper midwestern big crappy building supply store) just started carrying 4x8 sheets of 3/4" Baltic Birch for $60. I was about to buy four sheets a build up some BIB's for my hemps. Then I got a gig working around 80 hours a week for a campaign. The good news is, come November, I'll be unemployed and have some $$ for plywood. In the mean time, the hemps sound awfully good as is.
Back in the neighborhood of page 22, GM conjurred a ML BIB for the Ascendant Audio Assassin 10 sub (double the CSA of the orignal TC design, but with an 8x8" vent). I can't remember where I put the chart he sent me, but I think it's worth inclusion in the BIB bass horn page, as the work is already done.
Paul
pjanda1 said:
Greets!
Hmm, I can't help but wonder if it's the 'real deal' grade wise since AFAIK the top grade 13 ply we want only ships in 150 cm square sheets per Russian export standards, though there are numerous lower grades that conform to our building codes. Not to mention the relatively cheap price since the square sheets cost more than this locally.
My SWAG is they're offering furniture grade at best (A/B, or more likely, B/B), which can have putty filled knots, internal splits, etc., which can potentially wreak havoc in a speaker app, so Caveat Emptor.
GM
pjanda1 said:
I'll give the 'me too' for the inclusion of the Assassin in the
BIB's for basshorn. It looks to me my pick if I ever go sub.
OT: can the Assassins run with one of those inexpensive MCM
or PE sub amps? I have a jack out of a Yamaha RP U100 to
connect a sub. 'Got no idea what it would do.
I spoke with some levity. But I wish it were like that in the North East of the UK. A medicore sheet of 18mm birch ply riddled with voids, sets us back £36.95 from B&Q. It's not sold by them in thinner sheets, though we do have the option of 3 or 5 ply spruce, with even more voids, for about £25, which is only useful for boarding up smashed shop windows. It's very low quality stuff.
Void free is not sold at all in my area, nor do I know of anywhere that will deliver it -most suppliers only deliver within a set radius, and there aren't any near me. Those that do stock it elsewhere seem to be under the impression that £70 a sheet is good value too.
That's why I use MDF. Not great, but sensibly priced, and I'd rather have a sheet of that than a sheet of something of duff quality that costs 3 times as much.
Void free is not sold at all in my area, nor do I know of anywhere that will deliver it -most suppliers only deliver within a set radius, and there aren't any near me. Those that do stock it elsewhere seem to be under the impression that £70 a sheet is good value too.
That's why I use MDF. Not great, but sensibly priced, and I'd rather have a sheet of that than a sheet of something of duff quality that costs 3 times as much.
GM said:Greets!
All of these RS drivers have too high a Qts for a BIB, with the 1286 being the lowest by far.
GM
Scottmoose said:
Thanks for looking at them! Too bad, though. I wonder if something like (MJK or Nelson Pass)'s Pioneer box would work for them? I've searched the web over for mention of them, but, can't find them, here's the pictures associated with them, maybe they'll jog someone's memory:
Attachments
Please don't shoot me .... but looking around for bright ideas for my problems with materials
availability/cost, I came across a discussion on world-designs forum.
Chipboard over MDF or PLY. petercom suggests "the advantage is that it has controlled resonant
behaviour and reduced 'leakage' of sound from inside the cabinet, and this applies across the
frequency spectrum."
Any thoughts? And remember don't shoot the messenger.
availability/cost, I came across a discussion on world-designs forum.
Chipboard over MDF or PLY. petercom suggests "the advantage is that it has controlled resonant
behaviour and reduced 'leakage' of sound from inside the cabinet, and this applies across the
frequency spectrum."
Any thoughts? And remember don't shoot the messenger.
I doubt anyone will shoot you. Peter was head designer at Mission, so he knows what he's on about.
It very much depends on the application -what works for one thing doesn't automatically work for everything else. I've laminated 3/4in MDF to 1/2in chipboard with good results. And there certainly is a school of thought that suggests that chipboard is superior to MDF in some ways -considering how cheap it is, you won't hear any complaints from me... ;>) Like ply, it has a broader spread of resonances than MDF, which vibrates unpleasently, at, if memory serves, 1.1KHz, though for very large cabinets I think it's a bit too lightweight on its own. It probably doesn't store energy to the ame extent. Swings and roundabouts.
It very much depends on the application -what works for one thing doesn't automatically work for everything else. I've laminated 3/4in MDF to 1/2in chipboard with good results. And there certainly is a school of thought that suggests that chipboard is superior to MDF in some ways -considering how cheap it is, you won't hear any complaints from me... ;>) Like ply, it has a broader spread of resonances than MDF, which vibrates unpleasently, at, if memory serves, 1.1KHz, though for very large cabinets I think it's a bit too lightweight on its own. It probably doesn't store energy to the ame extent. Swings and roundabouts.
renfrow said:
Greets!
You're welcome!
Didn't know MJK designed one, but NP's pipe is way too small acoustically since the 1286 wants to 'feel' a ~48.15 ft^3/19.4 Hz load! At the very least it appears to 'want' ~12.72 ft^3/37.5 Hz, so I simmed it in his pipe to see how bad it would be, and while the sim doesn't look as bad as I assumed, it can't show how 'choked' it's likely to sound, but a tweeter can offset it somewhat. Only one way to know for sure though:
GM
Attachments
GM said:
<wince> 3ft x 4ft x 4ft cabinets would be a little unwieldy
</wince>I'd forgotten who had designed that speaker, and couldn't remember closer than that
I think I'll get the wood for a pair and build it as is, and plug each of the 8in speakers into them to see how they sound. If nothing less I can still buy a pair of the pioneer's and plug them into it! I've got two sheets of 4ft x 4ft wafer board that I've been plugging them into, in the basement, and they're not really ready for public listening Thanks!
Tom.