Q

qwaven

Audioholic Intern
Hello all,

I've been trying to understand more on how to size a sub for my space. I don't have anything terribly fancy for a setup speaker wise but still would like to try.

I am hoping to eventually have 4 subs total, one in each corner of the room.

The room is about 10x10 to 15x15 feet give or take.

I currently have 1 sub which is 250w dual 8"

so a few questions I have are:

1. When getting multiple subs, how does the watts equate? IE the sub I've been eyeing says its 300w, does that mean if I have 4 I would essentially be running 1200w? Or is there more to this...

2. What is the advantage/disadvantage in getting larger or smaller speaker sizes on a sub?

I realize my AVR will attempt to balance things in the end with my other speakers (when running the calibration) so I am a little unclear how much it really matters?

To summarize what I have...

Yamaha A8A AVR
5 main speakers all around 100 or so watts various brands (eventually will add 2 more to make 7)
4 height speakers

I've been leaning towards the KEF Cube which seems about at my price point.

but again based on my questions or any other thoughts would I do just as well with the cheaper 8" version or would I feel I am lacking vs the 10" or maybe something else?

Cheers!
 
everettT

everettT

Audioholic Spartan
Hello all,

I've been trying to understand more on how to size a sub for my space. I don't have anything terribly fancy for a setup speaker wise but still would like to try.

I am hoping to eventually have 4 subs total, one in each corner of the room.

The room is about 10x10 to 15x15 feet give or take.

I currently have 1 sub which is 250w dual 8"

so a few questions I have are:

1. When getting multiple subs, how does the watts equate? IE the sub I've been eyeing says its 300w, does that mean if I have 4 I would essentially be running 1200w? Or is there more to this...

2. What is the advantage/disadvantage in getting larger or smaller speaker sizes on a sub?

I realize my AVR will attempt to balance things in the end with my other speakers (when running the calibration) so I am a little unclear how much it really matters?

To summarize what I have...

Yamaha A8A AVR
5 main speakers all around 100 or so watts various brands (eventually will add 2 more to make 7)
4 height speakers

I've been leaning towards the KEF Cube which seems about at my price point.

but again based on my questions or any other thoughts would I do just as well with the cheaper 8" version or would I feel I am lacking vs the 10" or maybe something else?

Cheers!
Just gonna note that watts don't matter when determining a subwoofer purchase. Since your room isn't large sealed subs or ported will be fine. It comes down to how much performance you want and what budget you have. The most important pieces are your front 3, with the center being the most important with video and the subwoofers.
 
lovinthehd

lovinthehd

Audioholic Jedi
The watts have little to do with comparing different subs. They're largely irrelevant altogether if the sub is well designed and an appropriate amp for its capabilities was provided. If you had information on the impedance and sensitivity of the sub, which is rarely provided, maybe you could make some comparisons but still largely not all that useful as you really need third party testing to show various actual differences in performance parameters. One generalization you might make is that a ported sub is a more efficient design, and often a sealed sub needs more power to account for the poorer efficiency as well as equalization that is often needed in the lower frequencies (eq takes more power from the amp than no eq).

Don't know what sub you have but 8" drivers are on the small side of things subwoofer. A 10" would generally be more capable. If the room is square that adds some acoustical challenges that multiple subs could likely help out with. Corner placement may or may not work well, altho corner placement does offer more boundary reinforcement.

Generally I'd start with the sub specialists like SVS, Hsu, Rythmik, Monolith, etc. The Kef's spec isn't horrible for the $ but think you can do better.

Might try this article on room size and subs https://www.audioholics.com/loudspeaker-design/subwoofer-room-size
 
ryanosaur

ryanosaur

Audioholic Overlord
Power ratings for judging subwoofers are not a wise path to follow as many other variables are needed to understand what that means.

Here at AH, there is a handy thing they still do which is the Bassaholic Room Size Rating Protocol.
Beyond that, you would need to spend a little time looking at what matters in Subwoofer measurements and how that may apply to your specific needs.
Sadly, this can still be complicated.

Key information is:
What do you want out of a Subwoofer?
If Movies are your main thing, how low do you want the Subwoofer to reproduce? If you want to feel the earthquakes and planets blowing up, you probably want something that has Infrasonic (below 20Hz) Extension.
If you just want something to fill in the bottom octave missing from whatever Speakers you use to better enjoy Music, you don't need to chase that.

Also, how loud?
 
Q

qwaven

Audioholic Intern
Hi all,

Thanks for your inputs.

I will try and answer.

My primary use is for movies but I do also utilize for music purposes as a secondary use.

The idea of infrasonic is appealing but figured it would be out of my budget. The SVS PB-1000 is more but its not drastically more so that's something. Monolith seems also possible. Will do some more checking.

I guess what I was hoping for with this was to better define why a sub would have 12" vs 10" etc ie in laymans terms what is the generalized expectation that a larger (or smaller) driver would achieve?

Is it really expected to be worth the cost to get 4 subs in smaller space or am I better off getting 2 better subs? My understanding was with 4, one per corner -give or take- would cover all listening spaces with a more equal bass response. This is one of the reasons for picking the KEF one as it would be on the smaller side and tuck away in each corner. Advertises some pre sets for placement options like corner use. Not really sure what the actually does but seemed interesting. :)

Cheers!
 
lovinthehd

lovinthehd

Audioholic Jedi
Sub driver size is mostly about moving air. Motor strength/driver excursion capabilities also come into play, as well as the actual box size for the driver's particular T/S parameters (Thiele/Small parameters). Larger subs and larger sub boxes generally have higher performance, both in terms of extension (how low it goes) as well as spl (how loud). Relates to Hoffman's Iron Law of speaker building. Multiple sealed subs in small rooms also get some cabin gain, which can help out, but sometimes corner loading can be too good a thing (and midwall better perhaps). Multiple subs don't particularly provide more extension, though, you're pretty much limited by your least denominator sub on that score, altho that cabin gain with multiple subs can help out some. Don't know what Kef advertises for integration help, but I wouldn't consider Kef subs generally at all.
 
Q

qwaven

Audioholic Intern
Thanks for the clarification

That helps me put things more in perspective.

I guess I'm trying to still determine now if it's even worth doing anything. Turns out I've miss-remembered what I even have. I in fact actually have dual 10" not 8" as I wrote originally.

If I'm honest I can't say it does a bad job. Certainly not infrasonic though which I'm gathering should be something I seek out if upgrading given movies are my main focus. I definitely can localize where it is however.

What I do have to be specific is:
Sony SA-WX700
250 watt amp
Dual 10" long-throw woofers
Frequency response 20-200 Hz

I guess I'm still not really clear on if I were to upgrade how I should size 1 or more subs to compliment, rather than be dialed down a lot of it's to good for my speakers :)

Ie if I were to purchase something, any brand, how do I know what is wasting money or not spending enough? I've mostly looked at svs and monolith if you wanted to offer a more specific example.

I saw a question on how loud and I'm not really sure how to answer this. In general the sub(s) should keep up with my speakers, whatever volume. I don't have any other amplification other than my avr (Yamaha a8a) and I guess typically it is set somewhere around -50 to -40 but that's more because I need to be mindful of others.

Keep in mind I don't have any measuring devices. Just looking for more generalized idea, if possible. :)

Cheers!
 
ryanosaur

ryanosaur

Audioholic Overlord
If you choose to pursue an upgrade, I would urge you to spend a little time researching Subs and reading some of the reviews here at AH.
After that, consider at least 2 Subs. These should be placed in the room where they perform at their acoustic best. As every room is different, I can't really tell you where that would be. ;) This is where taking measurements can come in handy. On the other hand, a somewhat crude yet effective technique can be the Subwoofer Crawl to help find places in the room where a Sub will perform at it's best.

Major things to consider is the Total Open Room Volume of the space you will put the subs in. Saying the "theater area" of your home is only 12x12' or some such is useless, especially if you are dividing a much larger space simply by how you use it. Subwoofers work on the entire room volume they are exposed to, thus if you have an open floor plan rather than an actual closed room, you must consider all of that space!
Now, this is not to say you have to "pressurize" all of that open space, however, you should take into consideration that all that space will impact how the Subwoofer(s) perform where you are using them.
Beyond that, are you in an apartment with shared walls or floor/ceiling? Are you willing to rearrange to place a Sub where it will perform at its acoustic best? How many seats are you trying to make sound good?
To that latter, if you are only worried about 1 or 2 seats, your needs may well be different than if you are trying to get 2-3 rows of seating covered. ;)

One last tidbit is that you will control the gain on your Subs separately from running room correction which should help level match all of the Speakers including the Subs. Usually, you will set the gain so that they are outputting a test signal at a specific SPL which your room correction program will dictate (if it does at all). Once that is set, the room correction will hopefully then be able to match up all Speakers so the sound is uniform.
It helps if you can check that on your own using an SPL Meter or phone app.

In the end, this can be a complicated deep dive, or you can work a little to keep it simple.

The more Subwoofers you add, the more difficult it may well get. On your AVR, you will need to add additional gear to truly be able to control 4 Subs. Unless you are able to keep things perfectly symmetrical, that is... which will require a little bit of luck, too.

If you can answer the questions about total open room volume and consider where you are willing to place the Subs, then you should be able to easily move forward with a little more certainty about your choice!
 
lovinthehd

lovinthehd

Audioholic Jedi
Thanks for the clarification

That helps me put things more in perspective.

I guess I'm trying to still determine now if it's even worth doing anything. Turns out I've miss-remembered what I even have. I in fact actually have dual 10" not 8" as I wrote originally.

If I'm honest I can't say it does a bad job. Certainly not infrasonic though which I'm gathering should be something I seek out if upgrading given movies are my main focus. I definitely can localize where it is however.

What I do have to be specific is:
Sony SA-WX700
250 watt amp
Dual 10" long-throw woofers
Frequency response 20-200 Hz

I guess I'm still not really clear on if I were to upgrade how I should size 1 or more subs to compliment, rather than be dialed down a lot of it's to good for my speakers :)

Ie if I were to purchase something, any brand, how do I know what is wasting money or not spending enough? I've mostly looked at svs and monolith if you wanted to offer a more specific example.

I saw a question on how loud and I'm not really sure how to answer this. In general the sub(s) should keep up with my speakers, whatever volume. I don't have any other amplification other than my avr (Yamaha a8a) and I guess typically it is set somewhere around -50 to -40 but that's more because I need to be mindful of others.

Keep in mind I don't have any measuring devices. Just looking for more generalized idea, if possible. :)

Cheers!
Interesting sub from Sony, never noticed that one before. I usually wouldn't think of using a Sony sub....would like to see some detailed specs (or better yet, measurements) than its help sheet offers, tho https://www.sony.com/electronics/support/res/manuals/W000/W0009462M.pdf

I think you're fine starting with the main sub folk (assuming you're in the US) like the two you mention (plus Hsu and Rythmik among others), they don't sell poor subs and depends on your wallet and stomach for size of sub beyond their entry level models. DIY is another option.

I can't imagine any sub not keeping up with a volume of -50 to -40! That properly calibrated? My normal level for movie watching is -20 (and I don't consider that particularly loud), which is loafing along for my subs.
 
Q

qwaven

Audioholic Intern
Hi all,

Thanks for the replies.

I did do the sub crawl for my existing sub and found at least 2 spots that were most ideal, having to settle on the 2nd favorable spot re power restraints. Would still be planning to attempt again with the new one.

In regards to closed vs open concept room. The room sizes I gave were "estimates" as my final theater space is not built yet. I was more trying to plan and perhaps acquire the sub(s) now to temporarily occupy my temp space until I have a more dedicated space. The dedicated space and my temp space are likely to be very similar in size. The temp space is a little more open. The new space the plan would be to have a dedicated room with a door.

In terms of controlling the subs I was planning to use something like: https://emotiva.com/collections/subwoofers/products/vsub

This can take 1 sub out and send to 4 subs. Should in theory keep it symmetrical.

I do live in semi-detached house so I do have a shared wall with my neighbor. I am located in Canada. :)

In terms of calibration. Well I did run the Yamaha multi listening point automation and have adjusted some of the speakers a little manually since such as the center channel channel. But otherwise I have not done anything terribly fancy.

Cheers!
 
j_garcia

j_garcia

Audioholic Jedi
Crawl method for the old sub won't apply to the new one(s) :) They will have different output curves and as a result, different room interactions.
 
F

fmw

Audioholic Ninja
1. When getting multiple subs, how does the watts equate? IE the sub I've been eyeing says its 300w, does that mean if I have 4 I would essentially be running 1200w? Or is there more to this...
You won't even be using 300 watts. Not even close. The power rating is a maximum output fairly free of distortion. I'm not convinced that using 4 subs makes any sense. The audio at those frequencies is not very directional. Honestly I think the idea is related more to equipment collecting than audio. Others will certainly disagree.

2. What is the advantage/disadvantage in getting larger or smaller speaker sizes on a sub?
The ability to reproduce low bass is the capacity of the speaker system to move a lot of air. In general a larger driver in the subwoofer will move more air. There are exceptions, of course. So basically the larger the driver, the deeper the bass it will reproduce. I would rather have one 15" subwoofer than 4 8" ones. In fact that is what I have. If I ever replace that sub it will be with an 18".
 
Q

qwaven

Audioholic Intern
Thanks for the reply fmw. That helps to clarify further into the simpler terms. :)

I had posted something before but not sure what happen to those posts. Seems like they were deleted or something...?? Anyway in short it was another KEF sub https://us.kef.com/products/kf92-subwoofer which does have smaller drivers but based on some other reviews found that it still offered some competitiveness to larger subs. Found it interesting mostly as it offers a smaller footprint for people like me with limited space. :)

Cheers!
 
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