Move my Alpair 10p to sealer boxes now that I have subs?

Hello,


I made some floor standing pensils a few years ago when I was in a smaller space. I moved to a bigger space and wanted to upgrade the spl, low end, and clarity at higher volumes. While researching multi-way options it was suggested that I first try adding a sub woofer to add more lows and unburden the full range below 80-100hz. I ended up making a pair of nice little subs that play well up to ~100hz (pics here: SB23MFCL45 Stereo sub project)
Well now I’m curious if there would be any benefit of moving the full range drivers into a small sealed box that naturally rolls off those low frequencies, and gives better damping of cone movement. Certainly I’d be able to get smaller boxes closer to ‘coincident’ with my subs but I think they’re within a quarter wave right now. Being able to stack them would save some floor space too. But what about sound? Is a big ported box making trade offs to improve bass extension that I no longer need?


Thanks,
Brian
 
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I did it with 10M Gen 3 in 11.5L sealed. I build the boxes following the BBC principle (thin plywood walls, but damped with bitummen on the sides and top and bottom, front and backplate are 18mm ply that is screwed with a rubber seal between the plate and the box). It does sound way better than the 18mm ply 27L vented box i had before, even without a sub (but not much below 50Hz altough). I use them with a very low tuned 150L vented sub with a Scanspeak 26w/8534G00 but i'm building new sealed subs with the same driver (it's actually fit for that). But i crossover a bit higher (250Hz at the moment with a 1st order passive serial CR). The port i had before disturbed the sound of the stack as it was tuned to 40Hz, and that is in the passband of the woofer so... Sealed it sounds more defined and punchier than ported.
 
sealed works well with subs as a sealed cab rolls off at 12 db/octave.

but you should watch for baffle step losses from a small box. Maybe measure the
midbass from the sealed box or build a supr baffle for the sealed box.

a sub operated at 50- 100 hz will not likely give the midbass needed.

or, at least, in my experience. let us know how it works for you.
 
sealed works well with subs as a sealed cab rolls off at 12 db/octave.

but you should watch for baffle step losses from a small box. Maybe measure the
midbass from the sealed box or build a supr baffle for the sealed box.

a sub operated at 50- 100 hz will not likely give the midbass needed.

or, at least, in my experience. let us know how it works for you.



If you are talking about my subs. I’ll redo the crossover anyway as the response of a sealed box is different than a ported box. So i may change my cr frequency and layout.
 
but you should watch for baffle step losses from a small box. Maybe measure the
midbass from the sealed box or build a supr baffle for the sealed box.

I expect that the sealed boxes I make for the full ranges will be the same width as the towers they are in now. I did some baffle step compensation last night - just a simple -2bdb shelf above 400hz. It wasn't super scientific as my laptop is crashing when I run REW but to my ears it sounds much better. I'll be wary of changes and can use my DSP to correct as needed. Thanks.
 
I did it with 10M Gen 3 in 11.5L sealed. I build the boxes following the BBC principle (thin plywood walls, but damped with bitummen on the sides and top and bottom, front and backplate are 18mm ply that is screwed with a rubber seal between the plate and the box). It does sound way better than the 18mm ply 27L vented box i had before, even without a sub (but not much below 50Hz altough). I use them with a very low tuned 150L vented sub with a Scanspeak 26w/8534G00 but i'm building new sealed subs with the same driver (it's actually fit for that). But i crossover a bit higher (250Hz at the moment with a 1st order passive serial CR). The port i had before disturbed the sound of the stack as it was tuned to 40Hz, and that is in the passband of the woofer so... Sealed it sounds more defined and punchier than ported.

Hi waxx, glad to hear that worked out for you. Do you have a link to this "BBC principle"? It sounds cool. "defined and punchier" sounds like a step in the right direction.
 
Hi waxx, glad to hear that worked out for you. Do you have a link to this "BBC principle"? It sounds cool. "defined and punchier" sounds like a step in the right direction.

This is the original papers of the BBC:
http://downloads.bbc.co.uk/rd/pubs/reports/1977-03.pdf http://downloads.bbc.co.uk/rd/pubs/reports/1979-22.pdf

And google gives you a lot more info. Also there are some high regarded brands that build speakers following this principe like Harbeth, who supply a lot of technical info about this way of speakerbuilding on their sites.

Most of those speakers are ported altough. I tried it sealed, but with a solid wood frame inside the speakers that brace the thin wall cabinet.

Edit: added some pictures
 

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I put the driver centered in my 11.5L enclosure, that makes it easier to deal with baffle step in the crossover and makes the sound of the speaker more predicatble. Others put it off center to avoid that the baffle step i on the same frequencies, but in my experience it makes it hard to compensate for as it's unpredictable and more complex to compensate in the crossover.

As form of the speaker, i used golden ratio, but more of esthetical reasons than soundwise...