"Pro" Subwoofers for Home Use?

I always keep my eye out for interesting subwoofers. As such I have recently run across JBL's professional line of subwoofers and I was wondering if they would be appropriate for home theater/music integration.

In particular I found a B-stock JBL 18-inch 1000 watt model for $550 which piqued my interest. Link (I even found it for $400 used)

That's just one example on the cheaper end which I found. I'm also partial to their 1500 watt PRX818XLF. It gets kind of silly at this point, but they do offer value for money not common in typical SVS/Rhythmik caliber units.

So as a home user I am curious if anyone has any opinions on using such pro oriented subwoofers for home music/home theater use. There are some models which go deeper if that is of concern.

I have no doubt they would be capable of brute force, but I do wonder if they can handle the subtleties of blending with a home setup.

Though I think if I did aquire such a subwoofer, I have a feeling I would mainly be using it to feed my cruel amusement of startling guests

Those JBLs are not subwoofers in reality, they're PA bass units. A home theater subwoofer should have extension to 20hz or lower. This PA bass extends only to 31.5hz. Probably it will extend a bit lower inside your room - the specs are for open air or performing stage.

If you add DSP correction to a bass unit like this, it will perform great in your room. Without DSP - results are a turkey shoot. Because the unit is meant for extreme SPL playback it will have ample room for low end correction with a DSP before it reaches its limits at the volumes you use at home.

I have a chance right now to buy some G3 KRK 10-3 Studio Monitors for $500. But they are massive with 10" Subs, mids and tweeters.

What on earth would need an 18" Sub? lol.

But I bet your explosions in whatever movies sound real.

SixFootDuo said:

I have a chance right now to buy some G3 KRK 10-3 Studio Monitors for $500. But they are massive with 10" Subs, mids and tweeters.

What on earth would need an 18" Sub? lol.

But I bet your explosions in whatever movies sound real.

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If you haven't experienced a proper sub in action you can never even realize it. With a 18-24" sub or three, movies have a whole another dimension. When you have an explosion you don't get a 'boom'. You get your floor shaking and a slam that you feel in your gut. Most people have never experienced it so they don't actually know what they're missing.

My movie theater horn subwoofers have got customer feedback stating that the experience is almost the same like the '4D' seats in some theaters where the seat moves and vibrates with the effects.

B00nie said:

Those JBLs are not subwoofers in reality, they're PA bass units. A home theater subwoofer should have extension to 20hz or lower. This PA bass extends only to 31.5hz. Probably it will extend a bit lower inside your room - the specs are for open air or performing stage.

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+1. For a given size of enclosure, deeper bass forces lower efficiency & vice versa. HT subs lean to deeper tuning, while pro subs skip the bottom octave to increase efficiency/output.

Examine driver specs, and you'll find the same factors at play. A 15" pro woofer might have Fs around 30Hz with 5mm Xmax & 95+dB sensitivity. The same company's 15" HT sub would be closer to 20Hz, 10+mm & 85-90dB.

As usual, I recommend playing with WinISD or similar to get a feel for the various trade-offs.

If you add DSP correction to a bass unit like this, it will perform great in your room. Without DSP - results are a turkey shoot. Because the unit is meant for extreme SPL playback it will have ample room for low end correction with a DSP before it reaches its limits at the volumes you use at home.

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I agree that EQ can convert unused output capability into deeper extension, but I see 2 potential issues here.

1. Low-excursion woofers can hit Xmax easily when you EQ deeper extension. (Flat response requires 4x cone excursion as the signal drops an octave.)
   
2. Ported boxes lose control below their tuning frequency.

#1 probably doesn't matter in this case, because the pro sub has massive output levels for in-home use. I'm not sure how big an issue #2 is. B00nie?

Oh, also! Because bass is so affected by room dimensions & placement, several smaller subs could easily beat that JBL. For example, you could buy 3x 12" Daytons for $450 at normal pricing. And I've seen them on sale for $99 each, delivered...

If you don't mind DIY, Fi's new 15" driver offers BIG output (1.5L Vd!) for $99. It prefers a large box & big amp. I believe you could get 1x box with something like a Crown XLS for $550ish, and have a spare amp channel for when you can afford to build a 2nd box.

HammerSandwich said:

+1. For a given size of enclosure, deeper bass forces lower efficiency & vice versa. HT subs lean to deeper tuning, while pro subs skip the bottom octave to increase efficiency/output.

Examine driver specs, and you'll find the same factors at play. A 15" pro woofer might have Fs around 30Hz with 5mm Xmax & 95+dB sensitivity. The same company's 15" HT sub would be closer to 20Hz, 10+mm & 85-90dB.

As usual, I recommend playing with WinISD or similar to get a feel for the various trade-offs.


I agree that EQ can convert unused output capability into deeper extension, but I see 2 potential issues here.

1. Low-excursion woofers can hit Xmax easily when you EQ deeper extension. (Flat response requires 4x cone excursion as the signal drops an octave.)
   
2. Ported boxes lose control below their tuning frequency.

#1 probably doesn't matter in this case, because the pro sub has massive output levels for in-home use. I'm not sure how big an issue #2 is. B00nie?

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Well, both can become an issue naturally. It all depends how loud you need it to play. If you're looking for 120db at 20hz - a single box like this probably won't cut the mustard. Impossible to say without seeing T/S parameters.

You can’t drive an 18” properly unless you have serious Amps.
I use QSC KW-181s, RCFs, d & b, Behringer, but ended up using a Fishman Sub.
It’s pro line gear but is perfect for the in yo neighbors face HTPC.

Check them out at Sweetwater.
Fat bastard will part your hair.
Don’t worry about specs on subs.
Trust your ears.
You like fat bastards you’ll love the Fishman.

jamesv said:

You can’t drive an 18” properly unless you have serious Amps.
I use QSC KW-181s, RCFs, d & b, Behringer, but ended up using a Fishman Sub.
It’s pro line gear but is perfect for the in yo neighbors face HTPC.

Check them out at Sweetwater.
Fat bastard will part your hair.
Don’t worry about specs on subs.
Trust your ears.
You like fat bastards you’ll love the Fishman.

Click to expand...

That's not exactly true. The larger the driver the higher efficiency it has so it can play an equal SPL using a smaller amplifier compared to a smaller driver. It's a myth that large speakers require large amps, it's actually exactly the opposite of that.

Of course if you are talking about getting maximum SPL out of the driver, then you naturally need a large amplifier if the driver is rated to handle like 10 000 watts. Even then most drivers will die to over excursion in most boxes way before the thermal limit is overcome.

I love scientific data and specs.
But I love sound quality more.
I’ll stick to my myths until scientific data, marketing and specs sound better.

B00nie said:

That's not exactly true. The larger the driver the higher efficiency it has so it can play an equal SPL using a smaller amplifier compared to a smaller driver. It's a myth that large speakers require large amps, it's actually exactly the opposite of that.

Of course if you are talking about getting maximum SPL out of the driver, then you naturally need a large amplifier if the driver is rated to handle like 10 000 watts. Even then most drivers will die to over excursion in most boxes way before the thermal limit is overcome.

Click to expand...

This.
My maelstrom 21" will shake the floor on barely 100W or you can feed them 240VAC 10A/2.4kW straight from a wall plug and they will take it like a champ.

There is no replacement for displacement.
So the answer is get as much cone and suspension while still reproducing sound well. Linear response is important, especially when you start pushing 20-30mm+ xmax one way.

If you need something WAF and big, build an ottoman sub 18-24".
Crown amps do fine for cheap, behringers also, but if you want the highest damping factor money can buy within reason, check out HPA amp kits.

https://holtonprecisionaudio.com/
I run two og version nxv800s which are each good for up to 1200W 2 ohms stable and 500w 8ohms, 1200 damping factor. Custom Avel Lindberg 1200VA toroidals with 1400VA cores like krell does to reduce magnetostriction.

One thing that is good to remember is that the amplifier damping factor is pretty irrelevant as long as it's more than 1 (tests have shown that anything more than 1 is not really perceptable). Even a short amount of speaker cable between the amp and the speaker already annihilates the damping factor.

The damping factor is calculated as the amp output impedance versus the speaker impedance. If the amp has an output impedance of 0.01 and the speaker is 8 ohms you get a damping factor of 800. When a speaker cable is added to the mix it easily adds 0.25 ohms or more of impedance to the formula. The resulting damping factor is suddenly only 30 or less...

So basically if you want a good damping factor out of your amp you need to attach the amp to the sub and pull as short a cable as possible.