Unfortunately the form factor of the Cornucopya speakers won't work in this situation (I've got about 8" between obstructions and the wall's edges, which are doorways/apertures on either side of the TV). I'm going to make a pair for my office though 🙂
@GM - kudos to you, Scott and everyone who's worked on the BIB thread for the last 18 years 🙂 I've been reading bits and pieces of it, and the impressions people have given of them are very positive! Given that the vent for the BIB is a horn mouth that takes up (almost) the entire cross-sectional area at the top of the enclosure, mushing it around in my brain a bit I think I'm starting to catch up with your thoughts 🙂
Given the loading that you've mentioned earlier in this thread that the ceiling will do, and therefore allowing us to increase the area of the vent, does it make sense to leave the end of the enclosure open, given its small-ish cross-sectional area, and then just work out how far that mouth needs to be from the ceiling?
I feel like I'm repeating what you've said earlier with that, so I apologise - I think I'm finally starting to catch up! I built a couple of Bill Fitzmaurice's T18 subs almost a decade ago now, and one of the placement recommendations he has for them is to fire them into a corner from a certain distance away, and in doing so it would give an extra octave of extension. I'm hopeful that the approach for the on-wall MLTL is similar, and that I've understood!
If I have understood, then my next question is about the notched vent. I can't visualise it, so I'll see if I can find an example on these forums where someone's hopefully taken a picture of two 🙂
Here's a CAD image that shows a rudimentary setup of the speakers on the wall in question. Note that the ceiling and floor extend past the wall on both sides, as there is an alcove on the left, and a door on the right.
@GM - I hope this helps. If you're able to draw on this picture to show how you'd do the 'horns' and/or the 'notches' that you've described, that would really help 🙂
@GM - I hope this helps. If you're able to draw on this picture to show how you'd do the 'horns' and/or the 'notches' that you've described, that would really help 🙂
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No drawing options, but I was suggesting them when we were still (I thought) talking about extending the cabs to the ceiling; for leaving a gap as shown, there's ~no advantage compared to a slot vent on the front other than maybe cosmetic to some.
This custom Altec 604 corner cab has small ones on the front sides whereas yours would be on the back sides and probably somewhat larger in comparison for the MLhorn, otherwise just small vents since there would be two of them.
This custom Altec 604 corner cab has small ones on the front sides whereas yours would be on the back sides and probably somewhat larger in comparison for the MLhorn, otherwise just small vents since there would be two of them.
Thanks for your patience 🙂 The custom Altec 604 explained a lot! With that in mind, does the attached picture show what you'd been thinking of initially?
The maximum length of the MLTLs, if I go all the way up to the ceiling, is 72.75". With that knowledge hopefully that gives us one less variable when it comes to calculating the vent sizes.
The maximum length of the MLTLs, if I go all the way up to the ceiling, is 72.75". With that knowledge hopefully that gives us one less variable when it comes to calculating the vent sizes.
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Hmm, at this length, ~13543/4/72.75" = 46.5 Hz, it's extra (Vb) adds enough extra acoustic loading to significantly reduce amount of damping required, which in turn adds a bit of extra LF power eff./gain, so a good plan and just make the vent a cutout = its bottom area (i.d.) or gap the pipe by shortening it either ~2.25" or just dropping it down and move the driver up 2.25" as the reduced damping is still sufficient enough for it to make no audible difference.
Or you could roll that into a pizza box square format like what you did before and have the vent located closer to the main driver output vs 5 feet away (which may cause some spatial coherence issues). It’s a different look of course. Also a simple hairpin fold will also cut down the total length and have the output much closer to the driver.
Unfortunately, I don't have enough contiguous wall space to make a square enclosure like in post #1 🙄
The maximum width I've got is 8 inches, so I'm stuck with the long and thin form factor 🙂
The maximum width I've got is 8 inches, so I'm stuck with the long and thin form factor 🙂
I made a quick mock-up of the speaker, and I've been testing it out. It sounds quite good! However, compared to the MLTL i'd put together in post #1, there seems to be an audible reduction of the midrange. I'll keep trying different test material, but would there be anything obvious causing this?
Thanks @djn - very obvious now that you've pointed it out!
It still seems a little ironic that I'd need circuitry for a 2-way system that doesn't need any crossover components, but given that we're limited by form factor, I suppose it's not too much of a lift.
Using this site, I ended up calculating a simple BSC circuit as follows:
Is there more to it?
It still seems a little ironic that I'd need circuitry for a 2-way system that doesn't need any crossover components, but given that we're limited by form factor, I suppose it's not too much of a lift.
Using this site, I ended up calculating a simple BSC circuit as follows:
Is there more to it?
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Usually with a soaker flush against a wall, there shouldn’t be too much baffle step loss - it could be that the bass is very prodigious and is overwhelming the mids? In which case, a higher sensitivity midrange/woofer could help.
The depth does represent a disturbance and a larger baffle is a place where wavefronts can develop before such a disturbance. You could also use edges that are less square.
Alright, so I've been musing on this a little, and I have another option, given the form factor of this speaker:
- My wife reminded me that we have small children, who will attempt to swing on anything that looks 'fun'. This moves them out of the way 🙂
- Putting the speakers up at the ceiling allows us to create an angled baffle - probably something like 20 degrees down into the room. Would that integration with the ceiling aid the midrange?
- I didn't draw it in the picture, but the open ends of the enclosure wouldn't be hanging in free space; there is a certain amount of wall above each doorway that they can affix to
- This also means that sound can travel horizontally towards the side walls (at least, on the left side)
- I suppose the simple question here is: would this layout help the speaker?
FWIW, this is/was my fave way since nearly all my DIY speakers whether I made them and/or helped others to make theirs were either in college and/or married with pets and/or children in small apts., etc., so a couple of 'L' shaped metal shelf bkts. screwed to wall studs and underside of speaker with some air gap/fiberglass insulation above if a downstairs apt. to damp the worst of the bass, though normally put the drivers to the corners to help efficiency and further reduce bass eff. and use EQ to 'taste'/neighbor tolerance.