question about running 2 subs

do it--do it now!
just calibrate it and see how you like it. probably wont hurt unless the old one doesnt sound good...

I wouldn't bother. It won't add much SPL wise, and if anything, it will sound sloppy compared to the SVS sub. If it isn't every bit as tight as the SVS, it will only detract from your overall sound.

Yes and no. It obviously won't hit as low as the SVS but will help in the upper Hz range as far as filling in any nulls in you're room. I ran an eD A2-300 with a Energy ESW10 and while it couldn't hit as low as my eD it did help in over all fullness in the room. I do however have my eD paired with an SVS PC12-NSD which work together very well. I would defiantly give it a shot.

A lesser sub used with a significantly better sub will do nothing but hold the better sub back. The lesser sub will limit the total output of the *system" to the output of the lesser sub. Anything above that will cause the lesser sub to distort, compress or clip the output. Also, if the better sub has deeper extension, and the two subs are level-matched and calibrated to the rest of the system, the deeper extension of the better sub will be wasted.

I would definitely *not* recommend using an inferior sub with a much more capable sub.

Craig

Craig,

I'm a bit confused as I've thought that there were benefits to be had running two subs, even two different subs....one corner loaded and the other in a near field position, such as say using an Outlaw LFM-1EX 12" and a smaller Outlaw LFM-1c 10".

No?

That does make sense but I did liked the way my eD and Energy sounded together but made the switch since my Energy couldn't keep up with the eD on the lower end. I still think the OP should try and see if his ears can tell any improvement.

IF you are willing to go to the effort to integrate and utilize two (or more) dissimilar subs, you CAN get reasonable performance and even great performance. And by effort I mean placement optimization, careful measurements, EQ, etc.. If you can adjust your FR desirably all the way through the lowest end of your subs' combined output, then you are good to go. Otherwise, if you are just going to throw 2 subs in a room, level match them, and expect proper performance, it probably isn't going to happen. It may sound good to you, and it may even help with certain issues, but chances are, if one sub is significantly more capable on the low end than the other, you are probably going to underutilize it and actually reduce your overall output on the lowest end.

This man is correct if the 10" sub in question is crappy.

I wouldn't term the Hsu designed LFM-1c as crappy by any stretch.

Here are the basic specs of the two subs I'm running:
LFM-1c 10", 225w/RMS 1000w Peak, 25-180 +/-2dB, 112dB SPL max
LFM-1EX 12", 350w/RMS 1300w Peak, 16-180 +/-2dB, 118dB SPL max

Right, so, the affect of the room aside, and just based upon their specs, if you level match them to calibrate them, their combined output from 25Hz and up will be calibrated to the proper level, but the output of the EX from 16Hz to 25Hz, will probably be too low. Now, this assumes that you are level matching the subs. If you are using some other methodology or logic, and are able to achieve a flat response all the way down to the 16Hz capability of the more capable sub, then there is not an issue.

Just for simplicity and sake of discussion I am ignoring the fact that these subs roll-off below 25Hz and 16Hz.

Certainly, there are advantages of running multiple subs. However, most of the studies looking at multiple subs looked at multiples of the *same* sub. I know of no studies that looked at using multiple subs with *different* output capabilities.

If you run 2 dissimilar subs across the same frequency bands, then the limitations of the lesser sub will limit the output of the combined system. Maximizing the limitations of the lesser sub, (i.e., corner loading), will improve the output of the *system*, but you may still not be realizing the full capabilities, (SPL output and/or LF extension) of the "better" sub.

Using 2 dissimilar subs to cover *different* frequency bands can be beneficial. IOW, using the "better" sub to cover the deepest bass, while using the "lesser" sub to cover the mid-bass, can maximize the potential of both subs. However, this requires some kind of "crossover" between the two subs. It takes some sophisticated measurement and adjustment capability to optimize such a system.

If you have the equipment and the expertise to optimize a system comprised of 2 dissimilar subs, then you should certainly go for it. Otherwise, just setting both of them up to cover the entire frequency band,... you're just taking your chances.

Good luck.

Craig

I just received the 12" LFM-1EX so I'm still experimenting with placing it and my older 10" LFM-1c in the 30' x 16' HT room .

With AVR settings I already had initially dialed in before reading this thread, here is how they measured. Subs are crossed over at 80Hz and the mains sets at THX 80Hz vice full range. Obviously more tweaking is necessary to include improving the levels matching between the subs and the rest of the 7+1 (or should I be saying 7+2?) system. But from what I'm seeing, my use of both subs does look to be better than just the new one alone. Granted the 40 through 63 Hz spike is problematic right now but the 20 through 31.5 Hz range looks much better with both subs on line

Have you noticed more fullness at you're seating position with the two subs? My two are level match but still have a little more tweaking to do but have noticed a difference as well at my main seating position. Granted not huge but noticeable in my room and also took away some of my voids that where present. Of course my eD and SVS are closely match in performance versus my eD and Energy I originally had.

My post was directed to the OP since he didn't say what his 10" sub was.

In my experience having two different subs(if they're both decent) can be beneficial if you're not nearing their limits of either and you know how to properly integrate both for the benefit of smoother frequency response among a greater seating area. I've found the biggest issue is if the lesser sub starts nearing it's limits(doesn't even have be with objectionable distortion) you'll be able to tell where it's placed in the room. Placing it closer to you means it doesn't have to push as hard but it'll be even easier to localize the sub.

Again, if one of those is a crappy sub I say stay away.

With the smaller Compact, the "lightning" in the early scenes from War of the Worlds (Cruise) were very loud and shook the room whereas the somewhat later "earthquake" rumbling was barely there. Again this in a 30' x 16' room which really was stretching things for the Compact. Now with the larger EX the lightning is much less boomy but the earthquake sonics are incredible. I attribute all this to the Compact having being over stressed a bit and as a result exhibiting an over-emphasis of mid low bass frequencies while the EX more accurately provides what's really there as its capabilities are more suited to the size of my HT room. Now running both together mitigates against the stressing of the smaller sub while giving a more "even" across the board bass production. If that's what you mean by fuller, then absolutely.

Got it! The huge 40-63 Hz spike is GONE!

Granted, both the 160-200Hz and 40 to 50Hz ranges are a tad high but overall this is the best yet. And despite the moderate spike, the system doesn't react adversely now to the 40-50Hz content I'm seeing with OTA and Satellite HDTV feeds. Much more livable overall

Both subs with volume controls set around 10:30 o'clock or so. AVR set to cross subs at 80Hz, mains (which are 30-20k +/- 3dB) at 50Hz and all other speakers in the 7+2 system at 40 Hz. Table corrected RS analog SLM readings given:

1000 Hz 70.5 dB
200 Hz 75 dB
160 Hz 76 dB
125 Hz 73.5 dB
100 Hz 70.75 dB
80 Hz 72.75 dB
63 Hz 71.75 dB
50 Hz 73.75 dB
40 Hz 75.5 dB
31.5 Hz 71 dB
25 Hz 72.5 dB
20 Hz 73 dB

At 20 - 200Hz +/- 2.625 dB, these two dissimilar subs work quite well together And bets are that if I had test tracks at 16Hz it'd reflect a reading consistent with this curve.