[ACDOAN]

I have searched and searched for a powered or unpowered with powered or unpowered sub for a Karaoke system from JBL to Mackie, to QSC but to my disappointment that even with the 18" woofer, 1000W watt speakers, the frequency response only drops to in 40Hz to 60Hz. 
 
The same with some expensive Sub-woofer, the frequency is around 40hz the lowest.  
 
That leads to another question of the Home Theater application too. The JBL LSR 4328p monitor only drops down to 50hz and the JBL LSR 3212 sub only drops to in the range of 40hz.
 
What's up with the 20Hz-20KHz? I hate to come with the conclusion that the pro sub and pro monitors are suck. 

 

[Tablix]

Plenty out there once you start looking.. and there are specialist sub manufacturers.  User cel4145 is likely to give you some good recommends in the next week.  He is far more of an expert than me, I rarely use a system with a sub.
 
For studio use:
http://dynaudioprofessional.com/en/bm-series/bm-mkiii-series/bm14s-ii/
 
http://www.adam-audio.com/en/pro-audio/products/sub12/technical-data
 
http://www.adam-audio.com/en/pro-audio/products/sub15/technical-data
 
as for PA specific:
 
http://www.sweetwater.com/store/detail/SRM1850
 
http://www.sweetwater.com/store/detail/SLS18SAI
 
http://www.sweetwater.com/store/detail/QW218

 

[ACDOAN]

Thank you. The Presonus and the Dynaudio sub go down pretty low. 

 

 

[cel4145]

There are plenty of good home theater subs with solid 20hz response.

But for Karaoke? How big a room? Sub performance is directly tied to room volume. And what's your budget? No reason you can't use a home audio sub for that, assuming your budget can handle it.

Look into subs by SVS Sound, Power Sound Audio, Rythmik Audio, and HSU Reseach if you are in the US. These Internet direct companies provide excellent values. For larger rooms, focus on ported subs. For smaller rooms, a sealed sub may work because it can gain boost on the low end from room gain. Also depends, though, on how loud the listening volumes will be.

 

[RonaldDumsfeld]

ACGOAN. There is a jolly good reason why even mid to high end playback systems are rarely specified to go down much below 40Hz. If they did they would sound awful with music, particularly modern 'pumping' music.
 
Try it yourself. If you have a powerful, truly full range (20Hz-20kHz) system and turn the volume up above a fairly modest ~75dB. Your room will instantly split into a matrix of alternating suck outs (no low end) and peaks (really overloud bass). You might be able to engineer it so that in your chosen listening position you get a reasonable balance but the room in general will sound dreadful.
 
Assuming you live in a mansion and don't mind getting divorced a lot there are ways of taming that much radiant power in a domestic setting (room treatment, EQ, filtering, multiple subwoofers etc) but for most people, most of the time it makes sense to stop somewhere around 35Hz-50hz. The theoreticians claim 50Hz is all you need for music. hence the current popularity of 5" monitors. If you look at a FFT plot when playing music you will see the sense of this. There is very little information below 50Hz, even less of that is actually musically relevant and even if it was the problems the standing wave energy creates make reproducing it more trouble than it is worth.
 
The lowest note produced by an an electric bass would be 42Hz. The lowest note on a piano is in theory 27Hz but, since the string is struck 1/7 of the way down rather than in the middle the listening does not hear the fundamental anyway. Very few people listen to recorded church organ music.
 
With HT and gaming applications the situation is slightly different. You need to feel, rather than hear, the helicopter and the explosions etc etc. It doesn't really matter if the reproduction is accurate. It just need to go 'BOOM'. Occasionally.
 
You can get pro quality full range subwoofers but they are meant for 7.1 mixing, classical (with occasional very low notes) or to use in specially treated rooms often in arrays but for music in an average domestic setting you don't either need or want to go that low, that loud. It's counter productive.

 

[ACDOAN]

Thank you for enlightening me. Good info. 

 

[cel4145]

ACGOAN. There is a jolly good reason why even mid to high end playback systems are rarely specified to go down much below 40Hz. If they did they would sound awful with music, particularly modern 'pumping' music.

Try it yourself. If you have a powerful, truly full range (20Hz-20kHz) system and turn the volume up above a fairly modest ~75dB. Your room will instantly split into a matrix of alternating suck outs (no low end) and peaks (really overloud bass). You might be able to engineer it so that in your chosen listening position you get a reasonable balance but the room in general will sound dreadful.

That's not the reason why. You still have the problem with with peaks and dips with bass above 40hz as well. Subs with anechoic linear response down to 20hz are just more difficult to build/make.

With HT and gaming applications the situation is slightly different. You need to feel, rather than hear, the helicopter and the explosions etc etc. It doesn't really matter if the reproduction is accurate. It just need to go 'BOOM'. Occasionally.

I know plenty of HT enthusiasts who would disagree with that statement. Accuracy is also important for HT.