Side mounted woofers

[angel]

Does anyone here have experience in using side mounted woofers? I'm curious about how high you actually have to cross them over to get good integration, and what factors play into this.

When playing around with something like a 15" woofer, you're going to find that the front baffle gets huge. At the same time, smaller drivers don't always cut it. Putting the woofer on the side seems like a decent compromise. It also might get you a larger baffle, and thus better wavelaunch. (Depth causes less spouse aggravation than width, IME)

Obviously, the time difference will need to be compensated, and there may be other things that one will have to compensate for. I imagine lobing could get pretty weird with low order crossovers.

Anything else to keep in mind? And, again, how low does one need to cross over? I know of at least one commercial speaker that has excellent performance with a side mounted 10" woofer and a 250Hz crossover. Don't know what they've done to it, though.

[454Casull]

Don't larger panels resonate more easily?

[Brian Donaldson]

The speakers I last built use a side mounted 12" crossed at 120 hz. No problems. It lets me keep a narrow baffle and uses the depth behind the speaker instead of placing a small speaker a few feet into the room, I place the speaker almost against the wall and still have the baffle out where you want it.

454, A friend of mine has a Casull 454. I shot ot once. It's not fun. but a very nicely made arm.
And yes, a lot of internal bracing and deadening is needed.

[454Casull]

Not as bad as firing an S&W 500 Magnum...

Then you have those 20mm anti-material rifles... but they have anti-recoil systems. :P

[SY]

There are a lot of interesting things you can do with side-mounting, especially with regard to the acoustic loading. Study the NHT 3.3 and see how it's done by a real master of speaker design.

[angel]

Originally posted by 454Casull
Don't larger panels resonate more easily?

They do have a larger exciteable area, and a lower resonance frequency, etc.. Nothing that can't be relieved with a well-placed vertical brace and two different materials in the panel (e.g. wood + acrylic). The Helmholtz panels employed by the BBC are built in this way, using different materials with noncoincident resonances.

Originally posted by SY
There are a lot of interesting things you can do with side-mounting, especially with regard to the acoustic loading. Study the NHT 3.3 and see how it's done by a real master of speaker design.

I can't even find the 3.3 on www.nhthifi.com ... do you have a reference that I can read up on? I assume they haven't published any tech docs on their use of side-mounting?

[ingvar ahlberg]

I got this design to work realy good, the 12" cut at ~100, the 5" has no high pass. so they work in parallel up to cut off for 12"

[Frode]

Scroll down NHT 3.3

Frode

[angel]

Originally posted by Frode
Scroll down NHT 3.3

Frode

Ah, thanks. I'd missed that.

According to what they state here, they are using the junction between the cabinet and wall as a means to get the speaker to radiate into quarter-space instead of freespace (low frequencies rarely radiate into halfspace with normal baffle sizes). Should be quite nice for getting high SPL, and the early reflection gets to be very early, but varying the placement would change the output quite radically, wouldn't it?

For those who have posted about good results with <200Hz crossover frequencies, thank you, but my concern was whether or not I could expect good imaging while crossing at >200Hz, and what means I would need to employ to achieve said imaging.

[Rocky]

Originally posted by angel

my concern was whether or not I could expect good imaging while crossing at >200Hz, and what means I would need to employ to achieve said imaging.

The advantage of a narrow baffle does improve imaging by itself, but when using a side firing woofer design, IMO, it is not recommendable to cross higher than 200Hz. Period. I would say 150Hz is still a bit high. Remember you only want the side firing woofer to reproduce the spectrum where the sound is almost unidirectional, by means deep bass.

IMO you should go for a midbass and not a midrange on the front, and try to get your XO point down to around 100Hz.