Hear of "helper subs" ?

[ashok]

A friend wanted some information on what he and his friends called " helper subs". I think the name is inappropriate.
This application is for a home theater only.

Here is what they do. They all have the typical subs ( some supposedly going down to 15Hz).
Then they add a smaller sub ( 10 or 12 inch ) to bump up the upper bass from 70 to 140 Hz which I guess gives them some additional "punch".
This is connected to the main speaker output from the amp which is generally rolled off about 70 Hz to the main subs. The "helper sub" is rolled off at 140 Hz using the freq control on it's built in amp.

Is this a widespread practice ?

[Michael Bean]

Never heard of such a thing, I dont see how that could be useful for anything but over-emphasized bass. Reminds me of the clueless idiots that drive up and down my residential street with thier awful thump-thump-boom-boom noise. Does that make me a "curmudgeon"?
Mike

[ashok]

Yeah we have those "thump-thump-boom-boom " types here also. Luckily there are very few around. I'm tempted to tell them that they'll be deaf soon but which kid would listen to an old foggie ? It's very irritating to hear that boom however.

Regarding my friend and his pals, I think they want to feel some of the bass disco style. I asked him why they didn't use an equaliser to boost that freq region as it should do the same thing ( and they have 18 inch main subs !). They felt the added sub was better ( without trying an eq?) ! It would however give them more headroom in that range. They are adding 4 additional subs to achieve this at a cost of about US$5,000/- !

Could it be that some people take pride in and belong to the " How many dB spl does your home theater do ? ". If it can shatter all the windows the spl might be about enough !
What was that you just said ?......sorry you have to yell a bit, my hearing isn't what it used to be ( like when I was 10 !).

[salzburgsoundsystem]

I suspect (as a full time translator this kind of thing is not unusual) that 'helper' is the wrong synonym. Aux fed subwoofers are often summed to a mono signal and have their own level control. This is often used in progessional audio systems.

However, the frequency range referred to sounds more like that covered by what the Brits and others call kick bins - these are smaller bass speakers, used to handle the frequencies between the the low subwoofer and the higher mid-top loudspeaker frequencies.

Regards, Ben

[ashok]

That was illuminating !

That term 'kick-bin' sounds nice too ! They do want a kick in the seat of their pants.

Thanks.
Cheers.

[cyclecamper]

If you search a little, you can find some good papers on using multiple subs to activate different modes of a room, and make the bass more consistent everywhere. There's a huge benefit from using 2 or 3 subs, not for the amount of bass or directionality, but how it interacts with the room. But that's usually relevant to lower bass.

Your friends sound interested in adding some "slam" in a power-intensive range; lots of drum, bass guitar, and other percussive energy there in modern electronic music material. I call this the "slam" range; real visceral impact.

[Wayne Parham]

I've sometimes seen people refer to what I call "flanking subs" as "helper subs". They are used to smooth room modes, specifically those that are higher in the modal region, towards the Schroeder frequency. The reason for the name is the proximity to the mains. Multisubs are usually somewhat distant from the mains, and flanking subs are a specialized subset to provide smoothing of the midbass and lower midrange.

• Flanking Subs

[qguy]

I dont see why not, if the main subs aint good at the 70-140 hz range and higher, smaller 12 inch subs might just bridged the gap between the FRONT and the main subs

[18Hurts]

OK, I get it

They want additional subs for the higher bass for traditional music, the 18" takes care of explosions etc in movies. Since they are crossing them over so high, they are bass bins since you'll need 2 or 3 of them to sound correct for home theater.

No worries about the bass becoming directional if you're running 3 bass bins and keep the actual sub crossed low--should work great since it can be moved around for the best response from say... 15 Hz to 50 Hz.

Don't tell them about the ELF subs from BagEnd...they go down to around 6 to 8 Hz so they can have "infrasonic" subs. The most woofer boxes wins...

[revboden]

Would that be 7.1.2

Or even 7.2.4

ok, nuff kidding around... I've done that with 5-way systems.

subwoofer - woofer - mid - High mid - High

mostly in the late 80s ... good way to make expensive mud.

4 way is better, ashly makes a good crossover for that kind of thing. (xr 4001)