Got a subwoofer, but I'm not so sure I need it. Help :)

[benkatz]

Hey everyone.

So I just got a subwoofer and for the first time I had to take some measurements in order to calibrate it with my Stereo system.

My system is as follows:

Triangle Quartet Genese speakers - advertised at 35hz-20khz +-3db
Dynavoice T12 subwoofer - advertised at 500w and 23-200hz +-3db, crossover settings 35-150hz
Yamaha A-S2100 integrated amp
Cambrdige Audio CXNv2 streamer + CXC cd transport.

I've attached 3 pictures. The first 2 are from the Spectroid app of the measurments, first one without SUB, second with SUB after calibration. The 3rd one is a rough MS PAINT sketch of my listening room (all walls are solid).

I calibrated it, as specified, using the Spectroid app on my Sony Xperia IV which has (allegedly) high quality (for a smartphone) stereo mics. I ran an mp3 320 kbs file with 20-80 hz sweep. The line that is relevant here is the RED one.

In the first image, which is without sub, I was surprised to see that the energy that the speakers produce down to roughly 24hz is in line with the rest of the sub-bass range. This is quite a nice surprise considering the speakers official specs (35hz minimum). I understand rooms play a huge part.

The 2nd image is where it gets interesting. After multiple settings tests with the sub, I managed to get the most out of it with phase at 180 degrees (with 0 degrees I got less bass than without a sub), volume at around 40%, crossover at the lowest limit the sub offers, which is a 35hz cutoff. This way I got the most energy below the 24hz I got from the speakers alone, in this case, as you can see, the frequency cutoff went down to about 22hz with a bit more energy in the subbass area than without a sub, which is to be expected as the official specs of the sub say they produce down to around 23hz +-3db.

Now here's my dilemma. As much as I tried (and I tried different settings, multiple positions) I could not get a better integration and a lower extension than around 22hz, and that is quite good as this is all in-line with what the sub is advertised to be capable of. HOWEVER, given that my speakers (in my room) perform so good in the lower frequencies, and they can go with more than decent audible energy to roughly 24hz - does my system really needs a sub?

The audible differences are as you could deduce from the graphs. A bit more (but just a BIT) rumble, but nothing crazy, and judging by how low my speakers go, I'm not sure how much more the sound quality could benefit from a much much more expensive and bigger sub that could maybe add 1-3 extra hz down.

 

[Laserjock]

I couldn’t make it past the Left/Right speaker positioning…

 

[raindance]

You need to high pass the mains at a slightly higher frequency, say 60Hz to avoid overlap with the sub. Otherwise you are running the sub most likely below its sweet spot where it is already naturally attenuated and you will need to overdrive it to keep up with the mains in terms of SPL (which just adds lots of distortion). Contrary to what a lot of people say, using a sub crossed low like this will add absolutely zero impact; all the impact in music is in mid and upper bass ranges, well above the typical subwoofer range. I can't tell what the absolute SPL level is in your room, any idea? You have to be careful about measuring with the level too low (below about 75dB) because environmental rumble will add to the graph and confuse you about what your speakers can do. Did you try measuring with the amp turned off to get a background level? Also, it is helpful to measure one speaker at a time and then average them together rather than measuring both at once.

 

[Tangband]

Hey everyone.

So I just got a subwoofer and for the first time I had to take some measurements in order to calibrate it with my Stereo system.

My system is as follows:

Triangle Quartet Genese speakers - advertised at 35hz-20khz +-3db
Dynavoice T12 subwoofer - advertised at 500w and 23-200hz +-3db, crossover settings 35-150hz
Yamaha A-S2100 integrated amp
Cambrdige Audio CXNv2 streamer + CXC cd transport.

I've attached 3 pictures. The first 2 are from the Spectroid app of the measurments, first one without SUB, second with SUB after calibration. The 3rd one is a rough MS PAINT sketch of my listening room (all walls are solid).

I calibrated it, as specified, using the Spectroid app on my Sony Xperia IV which has (allegedly) high quality (for a smartphone) stereo mics. I ran an mp3 320 kbs file with 20-80 hz sweep. The line that is relevant here is the RED one.

In the first image, which is without sub, I was surprised to see that the energy that the speakers produce down to roughly 24hz is in line with the rest of the sub-bass range. This is quite a nice surprise considering the speakers official specs (35hz minimum). I understand rooms play a huge part.

The 2nd image is where it gets interesting. After multiple settings tests with the sub, I managed to get the most out of it with phase at 180 degrees (with 0 degrees I got less bass than without a sub), volume at around 40%, crossover at the lowest limit the sub offers, which is a 35hz cutoff. This way I got the most energy below the 24hz I got from the speakers alone, in this case, as you can see, the frequency cutoff went down to about 22hz with a bit more energy in the subbass area than without a sub, which is to be expected as the official specs of the sub say they produce down to around 23hz +-3db.

Now here's my dilemma. As much as I tried (and I tried different settings, multiple positions) I could not get a better integration and a lower extension than around 22hz, and that is quite good as this is all in-line with what the sub is advertised to be capable of. HOWEVER, given that my speakers (in my room) perform so good in the lower frequencies, and they can go with more than decent audible energy to roughly 24hz - does my system really needs a sub?

The audible differences are as you could deduce from the graphs. A bit more (but just a BIT) rumble, but nothing crazy, and judging by how low my speakers go, I'm not sure how much more the sound quality could benefit from a much much more expensive and bigger sub that could maybe add 1-3 extra hz down.

My and many others experience is that you will need two subwoofer to get full benefit of low bass. With only one subwoofer , no matter how good, the sound gonna be worse than without a subwoofer in certain points.

1.The bass articulation from the subwoofer must be better than the front speakers . Cheap subwoofers that are really good dont exist.

2. You always need two of them .
3. You need both a good lowpass and high pass crossover, with the correct slope.
4. Your main speakers must be set up in the room in the correct place so they play the best perceived bass quality before you even try connect subwoofers. This must be done by ear. The bass quality never gets better than the bass-articulation of your front speakers.

All of the above must be fixed IF the goal are really good music playback .

If you have other goals, like the sound from a jumping dinosaurus in a movie, anything goes.

 

[sarumbear]

You need to high pass the mains at a slightly higher frequency, say 60Hz to avoid overlap with the sub.

Very true but what can the OP do? Unless I’m mistaken they don’t have the HP filtering facility on their amp.

Contrary to what the entire subwoofer industry makes the market believe, subwoofer without a HP filter on the main speakers’ amplifier will never, ever going to work.

 

[ZolaIII]

@benkatz arguably those speakers don't need sub's. The crossover between mid range paper driver and fiberglass woffer's is at 350 Hz. They are all 16 cm but that's 4 such driver's doing sub 350 Hz range.
Edit: buy a UMIK 1 and use REW.

 

[ebslo]

Very true but what can the OP do? Unless I’m mistaken they don’t have the HP filtering facility on their amp.

Contrary to what the entire subwoofer industry makes the market believe, subwoofer without a HP filter on the main speakers amplifier will never, ever going to work.

The amp also doesn't allow the main input to be selected at the same time as another pre-amp input, so pre-out -> main-in cannot be used as an effect loop. It doesn't even matter whether the sub HP's the line-out because the amp can't use it.

 

[sarumbear]

The amp also doesn't allow the main input to be selected at the same time as another pre-amp input, so pre-out -> main-in cannot be used as an effect loop. It doesn't even matter whether the sub HP's the line-out because the amp can't use it.

I guessed as much hence a subwoofer cannot be used correctly with it. No point even trying.

 

[ZolaIII]

@ebslo you use Rec/PB for a loop and you can't have a high pass in the loop in the first place. As this is a solo analog amplifier without DAC that is not a concern. Plenty of sub's with integrated lo level line pass with high pass filter (usually at 80 Hz). Nothing stopping anyone to use something like MiniDSP Flex for a purpose. And again those speakers certainly can do without sub's.

 

[fieldcar]

I would just put a passive 80Hz high pass on both of your mains and then use a UMIK-1 + REW to figure out the crossover and gain for the sub.

Home

80 Hz High Pass 8 Ohm CrossoverConvenient crossovers that work great in any application requiring economical, flexible filtering. Also for use in car stereo installations with component speaker systems. Low pass, band pass, and high pass models complement woofers, midranges, and tweeters...

www.parts-express.com

 

[Matias]

My speakers are also specced to go to 32 Hz and I tried a sub and it made not much of a difference, even with bass heavy songs, so I am fine with the speakers by themselves.

 

[sarumbear]

I would just put a passive 80Hz high pass on both of your mains and then use a UMIK-1 + REW to figure out the crossover and gain for the sub.

Home

80 Hz High Pass 8 Ohm CrossoverConvenient crossovers that work great in any application requiring economical, flexible filtering. Also for use in car stereo installations with component speaker systems. Low pass, band pass, and high pass models complement woofers, midranges, and tweeters...

www.parts-express.com

How can you know that it is a 80Hz filter? A speaker's impedance changes wildly. What load impedance that filter is designed for? Have a look at a random speaker I chose. Impedance is on a steep slope around 80Hz, no simple two element filter can work as it is advertised. Don't get fooled by such devices.

 

[DVDdoug]

You NEED a subwoofer for home theater, otherwise the "point one" LFE channel is lost. If you have full-range speakers the AVR can be configured so the regular bass from the main & surround channels (and the bass with regular stereo music) goes to the regular speakers and ONLY the LFE goes to the sub.

Or there is "bass management" that re-roues all of the bass to the subwoofer. There isn't (normally) an option to send the LFE to the other speakers.

 

[sarumbear]

There isn't (normally) an option to send the LFE to the other speakers.

All AVRs I owned, Denon & Marantz had a facility to send LFE to the LR spekaers.

 

[fieldcar]

I tried a sub and it made not much of a difference, even with bass heavy songs

Even though I don't hear much of a difference with my 590 mains that go down to 30Hz in-room, you'll always gain a few benefits by running subwoofers.

1. Take the workload off the main speakers' woofer's. Nearing X-max means you get multi-tone distortion in upper bass and lower mids.
2. Take the workload off of the amp driving the main speakers. You can go MUCH louder and retain dynamics.
3. Multisub placement helps out with room modes and nulls. You don't really want all your subs beside your mains if you plan on fixing this.
4. Even with room correction, mains have issues with compensating for nulls, and you'll get less headroom and more distortion.

Though. It's not worth obsessing over. I'm perfectly fine running my 590's in a sub-less stereo mode.

How can you know that it is a 80Hz filter?

Most people are not able to build a custom crossover like a lot of us. Also, it's not a huge deal to not truly know the crossover point and its slope. The crossover will vary based on unknown impedance, but you can compensate with the UMIK+REW to whatever happens with the crossover. It's not perfect, but it's better than what OP's doing right now. I don't know how you could use a MINIDSP due to the RCA fixed output vs the amplifier's variable output. He's best off either ditching the sub or getting a different AMP/AVR instead of any of this butcher-like solutions.

 

[ZolaIII]

@DVDdoug it's not AVR or multichannel setup in the first place but plain stereo besides downmix to stereo for such from TV or PC or standalone DAC works just fine (when implement correctly anyway).

 

[sarumbear]

… it's not a huge deal to not truly know the crossover point and its slope.

Ha! If you say so!

 

[fieldcar]

Ha! If you say so!

I do something similar with my office setup. The 306pmkii's internal ~50Hz high pass with a 550P with no room correction is good enough in my book. Again, you take it way too seriously when it may be good enough for OP's situation, which is far worse off without some sort of change. If he's ok with enormous 30dB peaks and nulls from 30-120Hz, he should keep on with his crossover-less setup. I applaud you. That's brave advice right there.

EDIT: You know what. That was a bit too snarky. I apologize. What do you suggest he do?

 

[benkatz]

Thanks guys! Based on the relevant responses, meaning the ones that observed that I dont have an AVR receiver but a hifi stereo integrated amp which can't manage frequency cutoff for the main speakers (something that I'm not interested at all, I bought those speakers and the amp because I love how they sound and theres no reason to alter them, plus they werent cheap gear at all), I conclude that for my needs and gear, which as can be observed are music, the subwoofer I have works as good as I can hope, since they do fill out the subbass as specified. The issue is I wasn't expecting the main speakers go so low in my room, which isnt really an "issue" to have, I guess I'm rather lucky.

Im not really interested in getting another sub since, as can be seen in the graph, my system goes with linear energy all the way down to 22ish hz and with quite a lot of clarity, punch, and no boominess.

 

[ZolaIII]

No crossover whatsoever, single sub in a small untreated room with right placement and only one single and simple PEQ (blue). When thing's turn right of course.