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Subwoofers.... one 10" or two 8"?

I'm looking to fill out the bottom of my simple 2 channel system  (Musical Fidelity X-Ray CDP through Peachtree Audio Grand Integrated amp to a pair of Mirage OMD-15 full range speakers).  I occasionally will play the TV audio through the system for movies, but not interested in an HT setup. Music is the prime focus. The room is "medium" size.  I know that will not give the deep bass feel of a 12", but the difference should not be too great, and a 12" may be overkill for that room.  I've also considered getting two 8" subs to keep the sound balanced between the left and right channels. I think the  8" may be enough bottom for my room and tastes. I'm on a budget so getting a pair of anything bigger than 8" may not be in the cards.

Any opinions or suggestions as to whether I'd be better off with one 10" or two 8" subs?

















larstusor
emailists
923 posts
 
Dealer alert;   Current velodynes are sealed subs and are designed to play very low frequency 20 and below).  I use 2 10"'s for my room (dd10+ series ) which is 28x30 and 15 foot ceilings, which is a lot of cubic feet. 
I cross them over at 40hz from my TAD CR1'S.  
I probably should have gone with 12's or 15's but wanted to keep form factor as small as possible.   
I would suggest to OP that he buy one high quality 10"sub then add another as funds allow.   This way he'll have deep bass with one, then smoother bass when he adds the second. 
Anyone in NYC that wants to hear the velodyne dd10+ series contact me at Triodepicturesound.      
leotis
183 posts
 
If you can phase the sub perfectly to the mains you can get a lot more impact from even a small sub. This requires a sub with a continuous phase adjustment. (Not just 0 degrees or 180 degrees.) If your prepro can’t set a delay for the mains the best you can do is time align the sub 1 cycle late which is totally acceptable. Check: http://www.soundoctor.com/whitepapers/subs.htm
Play a pure tone at the crossover frequency with cable polarity reversed on main, dial phase on sub till you hear the null at listening position. Now perfectly out of phase. Switch to correct polarity on cable to main and now is perfectly in phase. Can’t overemphasize the importance of time alignment to SQ. Consider that a crossover or low pass filter at say 12 db per octave gives very large area of overlap. (40 Hz to 80 Hz is 1 octave. 60 Hz to 120 Hz is 1 octave) If the timing is out of alignment there is distortion of all the sound waves over a wide frequency range (partial cancellations and partial additions within each sound wave). Sounds like hell. Anyway, I have several systems going and several really good subs. Needed a sub for a 2 channel setup so I got a single 8" JL Audio Dominion D108, Just to add a little bottom to my "full range" Revel Performa F206s. Totally did the job in a 17’ x25’ room. Couldn’t believe it. Didn’t want to believe it (cause I wanted to justify a bigger sub purchase) Was not great until I phased it in however. Go ahead and scoff ye unbelievers! Went ahead an got a Revel Performa B110 sub anyway because it was prettier and the price was ridiculous. But can’t really say the resulting SQ is remarkably better, even though It does go a little lower. Set up properly the performance of a pair of JL Audio Dominions would beat any 10 sub that was set up improperly IMHO. :)
But them ain’t your grandpa’s 8" subwoofers.
danvignau's avatar
danvignau
935 posts
 

I have tried both, with varying, but excellent results with each.

For 25 years, I had some six foot tall electrostatics which originally had very sloppy cone subs. I also had a pair of NHT subs I hated.

I found some Peerless 8' and 10" sandwich cone subs, 8" for the

stats, an 10' for my B&Ws.

I really preferred the 8's, but they did not have the output I need for the  B&W's, so they went away with the electrostatics.

I have since upgraded these subs and use matching amps and preamps

for the mains and subs. After years of tweaking, the subs now reside between the B&W towers, time aligned with rulers. of course. This definitely sounds better on music than any subs my audiophile friends have brought by, 'though not as loud due to my (only) 125/250/400 (@8/4/2 ohms) stereo amp that drives them. 

leotis
183 posts
 
Due to "group delay" sound impulse leaves the sub usually 8-10 msec later than it leaves the main, even though the electrical impulse hits the sub and the main at the same time. So must be aligned by ear. Using just distance measurement doesn't work. Used to think there was something wrong with my autocalibration when it consistently made sub setting farther away than the actual measurement. Check:
http://www.theabsolutesound.com/articles/subwoofer-basics/?page=3
larstusor OP
59 posts
 
Someone please explain "time aligned"
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