One additional bit of info.
Mains are facing from the middle wall of the 3 brick walls (i.e. at the bottom of a brick 'U') and firing towards the partition wall.
So corner sub would be in a brick wall/brick wall corner.
Mains are facing from the middle wall of the 3 brick walls (i.e. at the bottom of a brick 'U') and firing towards the partition wall.
So corner sub would be in a brick wall/brick wall corner.
More subs are more of a PITA to get set up. But once you get them dialed in a single cant compare for a whole host of reasons. I always uses a minimum of two, up to as many as four.
I just started a multiple ultra mini sub project here http://www.diyaudio.com/forums/subwoofers/281795-suggest-me-extra-small-subwoofers.html
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I have had at least a dozen high end commercial subs and one of my favorites are sealed M&K k-9. I picked them over same similar size Rel They have some of the smallest footprints 9x11" standing on the sides. There real keepers.
Those subs do not look good. I'd go with larger drivers in closed boxes and external amps. MiniDSP is almost ideal for use in the multi-sub situation. I wouldn't bee too concerned with the GD as at these frequencies we are just not that sensitive to these delays.
My corner sub is in a three plane brick and concrete corner - but the other walls are very well damped.
Thanks for your replies Earl
When you say the subs don't look good - are you referring to SS4927s M&K k-9 subs or the SVS SB12-NSD in my post on page 176 of this thread?
Aim for heterogeneity - anybody who has taken Stats 101 will understand.
Actually, simple.
I started with a small box (1955 AR-1W) standing tall. After painting my music room recently, I was able to note about 8 locations covering half of the speaker-end of the room. Using REW (life is not possible as a DIY person without REW), I ran responses for each location with the mic where my head* always sits.
There were dramatic differences and I picked the good one.
I suppose there are interactions and complications and other fuss. But if you can get a reasonability flat and deep woofer curve, you're ahead of the game.
Simple.
Then you do it with a second speaker.
If you've taken Stats 101, you know the benefits diminish pretty fast after two subs, even though published tests suggest 4 is a good place to stop.
Now, the same logic applies to where your chair sits. But the chair may not be as easy to relocate as a speaker.
Ben
*"head" not in the nautical sense of the term
Actually, simple.
I started with a small box (1955 AR-1W) standing tall. After painting my music room recently, I was able to note about 8 locations covering half of the speaker-end of the room. Using REW (life is not possible as a DIY person without REW), I ran responses for each location with the mic where my head* always sits.
There were dramatic differences and I picked the good one.
I suppose there are interactions and complications and other fuss. But if you can get a reasonability flat and deep woofer curve, you're ahead of the game.
Simple.
Then you do it with a second speaker.
If you've taken Stats 101, you know the benefits diminish pretty fast after two subs, even though published tests suggest 4 is a good place to stop.
Now, the same logic applies to where your chair sits. But the chair may not be as easy to relocate as a speaker.
Ben
*"head" not in the nautical sense of the term
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I lost patience with svs ported boxes but of course others could have better results with them.
When I read your post at first, I didn't understand why you referred to SVS ported, since my current SVS is sealed.
But I can see that you probably interpreted the later part, where I say I plan to buy a couple of 10" or 1 x 10" + 1 x 12" ported, to mean that they would be SVS subs too. I don't think i worded it too well!
In fact I wanted to go for a different manufacturer for the other 2, because I thought it was best if all 3 subs are different. I was planning to go for a couple of the new XTZ models.
Re the SB12-NSD I have - its a sealed box, with a 12 inch Peerless XLS driver. As I understand it, that driver is quite well respected in the subwoofer world.
Note I'm not saying the SB12-NSD is a great sub, i'm of the opinion that it's probably a reasonable sub for its price range and age of design. But since I've heard only a very few subs I could easily be wrong.
Having said all of that, the first 90 pages of this thread plus things Ive read elsewhere, have led me to believe that 3 high quality subs aren't needed for the Geddes approach, that this thread is about.
I'm sure that somewhere in the first 40 pages theres a reference to something being on sale for $100 and someone saying 3 of those would work well!
So looking back at my original post I was asking 2 things really
1. Does GD matter and if it does should I focus on getting low GD subs. Earl says above that it doesn't - so thats good news!
2. Would 2 x 10" or 1 x 10" + 1 x 12" dual ported with the ports configured differently, (so they behave differently in the room) be a could choice for subs 2 &3?
Btw these are the XTZ subs XTZ 17 series You can see there's 12", 10" and 8" versions. I was assuming 8" would be too small - if not even better.
And there's details of my room in my 1st 2 posts.
All input welcome - as I don't want to pick up another 2 subs, only to find that I should've gone a different road.
rtrt If you are living in England at the moment get out and listen to some MJ Acoustics subs. You get much better deals on them then we do since there made over there. In my honest opinion they shame SVS subs, build fit and finish and sound. Ive owned a few different svs subs including an ultra, svs were some of the first ones. I used to think the world of them until I started hearing others. SVS are great for home theatre and not music. Its just my opinion. For music get out to listen to the rels and MJ and miller & kreisel, Rythmic servo subs are great too but Im not sure on there availability there. There are plenty of others but the few I mentioned happen to be a few favorite makes.
Though their current smallest sub is the pro 50. It has musicality in spades. If thats not compact enough they will be releasing a mini called the 'slimpact' no doubt to compete with the t-zero and other ultra mini's out there.
Ok thanks for clarifying. At this stage though, I'm struggling to get enough of an understanding of your approach, to make any meaningful progress in selecting the right subs.
Previously you've posted that the Polk Audio PSW10 for example was suitable, which I can see is a $80 (Amazon) to $150 (Best Buy) sub, so presumably fairly low end.
I couldn't find anything specific just now, but I'm fairly certain I've also read a few times, that you feel the quality of sub is relatively unimportant in your approach - that's presumably why the Polk is a good fit?
Other than the Polk, which I can't find for sale here in the UK/Europe, are you able to give a few examples of subs or types of subs that would be suitable?
Also if you could say what the issues are with the SB12, that would help me know what to avoid.
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I'm curious what makes you say that. ~100dB down to ~30Hz from a 14.5" cube sounds pretty good to me. Especially when used in multiples.
Aside from that, the Peerless XXLS12 a good driver a lot of us have used. It has a smaller diameter but longer coil than the B&C 12's; a variant of it with less throw* was good enough for the Genelec sub that had the highest output in the "Way Down Deep" series. SVS makes a solid cabinet. Amp power is adequate.
FWIW, several years ago I set up a modest system in a temporary rental apartment with a Geddes-style subwoofer arrangement. I mention that because the corner sub was very similar to your SVS, albeit with more output in the 20-40Hz octave. (More or less than passive radiator design in the Peerless XLS 12 Application Note, powered by a 240W plate amp. (Same one Dr. Geddes used to use, I believe.) The other two subs were KEF HTB2's, which have 10" woofers and 10" PR's in tiny "designer" cabinets. EQ was via miniDSP. Here was the final response, which required just three bands of global EQ after playing with relative gains for smoothest response.
An externally hosted image should be here but it was not working when we last tested it.
(Ignore the EQ sliders on the Velodyne SMS-1; it was used as a measurement device only; it was not in the signal path. Now there are much better measurement tools that cost less, but for its time the SMS-1 was a reasonably useful tool.)
It sounded like it measured: smooth and powerful. I don't listen at extreme SPL, and to be sure such a setup won't hit the "cinema reference" levels that HT forums discuss incessantly. But I was very happy with it while my big-bore gear was in storage.
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Yea, I am a little more cautious now after a couple of bad experiences. I found a cheaper sub had a very low threshold before the amp clipped. With added EQ this was happening well into the range of useful playback levels. So I tested a few of the internal amp subs and found that they almost all had very low clipping levels in the amps. If you are sure that you won't ever get the sub to this level then they would probably work fine, but the one characteristic of the sub in a multiple sub situation is that it can take all of the EQ that is thrown at it. If this gets violated then all bets are off.
I think that the small subs on the market have very low efficiency drivers (lower cost) and hence "larger" amps (more advertising "watts"). But the amps just don't have the headroom that they need.
I use hi-efficiency B&C 12 and 15 inch woofers in very small boxes and external amps of a better quality that the plate amps. I have never found this situation to cause me any grief. Hence I do not buy any off-the-shelf subs anymore, never found them to work as well, so I can't recommend any.
Lets say that your room need to boost the sub 10 dB at 40 Hz. Then that sub will now clip at 90 dB, a not so great level for bass. I am guessing, but I think that one of my sealed subs with a B&C 15" driver and a 400 watt amp would achieve something more like 120 dB before clipping. Again, there is no one answer here, but I have been bitten by the low clipping level of commercial subs before, and I noted that the one linked to had this same problem.
I don't know if its been mentioned already but Andrew Jones new Elac 10" and 12" subs have a pretty user friendly smart phone ap for set up between the sub location and primary listening position. I can imagine 3 of these in any normal sized room would be pretty sweet for the $ even if they don't quite hit a state of the art reference levels. I heard the S10EQ model and was impressed. subwoofers ? Welcome to ELAC Americas