Main speakers have lower extension than subwoofers

[unmutual]

I have a pair of Arendal 1723 THX S speakers (reviewed by Erin here), and in my room, I get great bass measurement from them down to 30 Hz. I have now tested two different subwoofers (both are old ones that I got used), and none of them perform better than the Arendal speakers in terms of bass extension. I am wondering if I really need a subwoofer in my setup, is it worthwhile looking for a sub that goes below 20Hz for music listening duties?

 

[alex-z]

For music 30Hz in-room extension is usually sufficient. However you may still benefit from a dedicated subwoofer if you want higher SPL, or to improve the smoothness of the bass response. In most residential rooms the optimal location for bass response does not coincide with the optimal location for stereo imaging.

 

[kyuu]

Just because your mains technically reach down to a certain frequency doesn't mean you have the same kind of SPL headroom or low distortion at those frequencies as a dedicated subwoofer.

If you have the space and budget for a large sub, then sure go for one that can do down to 20Hz properly. But I'm of the opinion that if you are limited by size, aesthetic, and/or budgetary issues, chasing that last 10Hz is counterproductive as you won't be able to get a decent response down there and the subwoofers which are inevitably DSP'd to extend that low are sacrificing too much in performance at the higher frequencies.

 

[OldHvyMec]

You have to consider a couple of things. Do you use records, and do you use valves in your gear?

I decoupled the valve gear, turntables, and the subs. I also have a few different rumble filters to choose from when playing records.

20 hz in a room isn't that easy to hit. You may be able to generate a tone of 20hz, but to use it in a home, it will rattle china all over the house. At least it does in my home.

30 hz is a lot easier to deal with, and in reality, 60- 100 Hz is what most people like for the chest thump. Below 60Hz, goes through your feet and bottom.

Regards

 

[raindance]

Honestly we'd need to see measurements of what is happening in your room in order to provide advice of any use.

 

[kemmler3D]

I am wondering if I really need a subwoofer in my setup, is it worthwhile looking for a sub that goes below 20Hz for music listening duties?

As others have mentioned, there are good reasons to get one or more 20hz-and-up subs, but whether they are important is up to you:

• Using them to smooth out bass response
• Getting higher SPL in the bottom octave
• Lowering distortion in the 20-80hz range (or so) by sharing the load across more speakers

Even if you don't need deeper bass than 30hz there are still ways subs can improve sound quality.

Also, you will often hear "music doesn't contain much below 30/40 hz" - which is sort of half true.

The true part: Most instruments will not play a note where the fundamental is that low.

However, a raw recording of any sharp transient (read: drums) DOES include frequencies all the way down to 0hz, bass drums in particular can become meatier with a sub. So any music that involves percussion can (in theory) benefit to some extent from subs.

 

[DVDdoug]

Note that with MOVIES a subwoofer is REQUIRED to get the "point one" LFE channel. You can configure the bass management in your AVR to keep the regular bass in the regular channels, and then the sub will only get the LFE channel (when it exists)..

 

[tomtoo]

No.

 

[unmutual]

Here are some measurements of the main speakers without and with PEQ, plus each of the subwoofers alone (no EQ):

 

[unmutual]

I guess I am just a little uncertain about how to integrate the subs properly with the main speakers, when both of the subs go down to appr. 30 Hz, whereas the main speakers seem to handle the 20-30 Hz range fine (however, I have not taken distortion into account as I have no proper way of measuring this).

 

[kyuu]

From what I'm seeing, you're needing a 10dB boost for your mains to be flat-ish between 50-130Hz. I wouldn't expect room modes to result in a such a low-Q dip, so that's kinda weird.

 

[alex-z]

Here are some measurements of the main speakers without and with PEQ, plus each of the subwoofers alone (no EQ):

Measure both subs combined. Then adjust the combined time alignment until you get maximum summation in the crossover region. I would suggest starting at 60Hz. Don't apply PEQ until the end.

That dip from 50-110Hz is unusually broad. I suspect your speakers are out of phase. Measure them indivually and see if the impulse responses match.

Also try measuring the subs with the ports sealed. They appear to have a high tuning frequency which adds group delay in an undesirable range. A shallower but earlier rolloff can sound superior.

 

[raindance]

You need to measure the mains one by one and repost. No EQ and no crossover applied. The 10dB boost you are applying is probably using all your amplifier power to compensate for a cancellation issue which is either due to speaker placement or listening position.

Forget about subs until you get the mains figured out.

 

[Chrispy]

Are they actual subwoofers?

 

[OCA]

I have a pair of Arendal 1723 THX S speakers (reviewed by Erin here), and in my room, I get great bass measurement from them down to 30 Hz. I have now tested two different subwoofers (both are old ones that I got used), and none of them perform better than the Arendal speakers in terms of bass extension. I am wondering if I really need a subwoofer in my setup, is it worthwhile looking for a sub that goes below 20Hz for music listening duties?

If your Arendals needed to be pulled well away from the front wall for best sound (like most speakers), I would suggest adding subs so you can move them close to wall and move the comb filtering effects above midrange but the polar plot shows they wouldn't mind being close to wall:

So, I wouldn't bother adding subs and the additional complexity that comes with them especially ones that can't go below your speakers.

 

[Chrispy]

If your Arendals needed to be pulled well away from the front wall for best sound (like most speakers), I would suggest adding subs so you can move them close to wall and move the comb filtering effects above midrange but the polar plot shows they wouldn't mind being close to wall:
View attachment 450810
So, I wouldn't bother adding subs and the additional complexity that comes with them especially ones that can't go below your speakers.

Can you expand along these lines? As to measurements speakers positioned as suggested with and without subs etc?

 

[unmutual]

You need to measure the mains one by one and repost. No EQ and no crossover applied. The 10dB boost you are applying is probably using all your amplifier power to compensate for a cancellation issue which is either due to speaker placement or listening position.

Forget about subs until you get the mains figured out.

Will do! Yes, this valley between 40 and 120 Hz seems very strange.

 

[unmutual]

OK, so I read a little about Speaker-Boundary Interference Response, and moved the main speakers closer to the front wall (distance is now around 10 inches). Also moved the listening postion forward. These 2 actions reduced the 40-120 Hz "valley" considerably. The green line below shows the resulting response from both speakers. Then applied some PEQ filters and got the red line, wich is the flattest I've seen so far. Still have a "Grand Canyon" at 186 Hz, but I did not try to correct this.

Whaddyathink - looks good now?

 

[raindance]

You're still using up all your amplifier power to fix the suckout at 120Hz which you can still optimize by placement. Why are you insisting on measuring both speakers at once? You'll likely find one of them is causing this issue more than the other.

 

[unmutual]

I have measured them indiviually, just didn't want to post an overload of info in the thread. Placement optimalization is tricky in what is a rather small space. I cannot move them much closer to the wall than they are now anyway. My 12 dB of boost in the 100 Hz area are counterbalanced by cuts in other places.