SWR SM 500..BEST WAY TO BI-AMP

[Denny Coon]

I'm currently running an SWR SM500. I'm using a Mesa Boogie Diesel 4x10, and have a diesel 1x15. Whenever i try to bi amp this I lose alot of power. I guess my question is, i want to add another small amp to slave into this to recover the power i feel like I'm losing. Any suggestions on wattage, brands or different ideas with a limited budget?? Also what is the correct way to slave it in

[Zooberwerx]

The correct answer is: don't biamp; use the full range cabs as full range cabs. If you're not sending any <100 hz content to the 4 X 10, that's probably why you are experiencing the perceived loss of power. OTOH, check the manual for whatever post-crossover outputs you may have available (does not include the speaker output).

Edit: Okay, I checked the manual and the 500 does not have biamp capability (assignment of highs & lows) so I'll assume we're talking about stereo operation whereas each amp "side" runs one enclosure...about 250 watts if I recall. That's not much power considering that you're working with Mesa cabs. If the enclosures are 8 ohm, you may want to consider running your amp in bridged mono and daisy-chaining the 4 X 10 and 1 X 15 although the improvement may only be slight. Your best bet in the quest for more ooomph (!) would be to snag a modestly powered power amp. Goes like this: run your SWR in bridged mono and run a single speaker cable to the 4 X 10. Send a line from the SWR's XLR out (in line level mode) to the input of your slave amp which will power the 1 X 15. Technically, this is not biamping as we know it but it is two amplifiers running two enclosures.

Riis

[billfitzmaurice]

Originally Posted by Denny Coon

I'm currently running an SWR SM500. I'm using a Mesa Boogie Diesel 4x10, and have a diesel 1x15. Whenever i try to bi amp this I lose alot of power.

You're not bi-amping, you're running dual mono. If you lose output when you turn up the second amp/speaker it's because your speakers are out of polarity, which usually is caused by one of the speaker cables being mis-wired.

[Zooberwerx]

Originally Posted by billfitzmaurice

You're not bi-amping, you're running dual mono. If you lose output when you turn up the second amp/speaker it's because your speakers are out of polarity, which usually is caused by one of the speaker cables being mis-wired.

Ooops...forgot about that possibility. To the OP: there's a quick way to verify cable polarity / orientation using a 9 volt battery and existing cables provided they're 1/4" > 1/4" phono plug type.

You may also want to verify proper connections & settings on the rear of the SWR. It is possible to inadvertantly hook both speakers to only one internal power amp. When all else fails, here's the manual:

http://www.bassemporium.com/pdfs/swrsm500.pdf

Riis

[Clark Dark]

if your SM-500 has left and right outputs on the back your solution would be to get a good power amp in a range that would provide the power you want at 8 ohms.

[billfitzmaurice]

Originally Posted by Clark Dark

if your SM-500 has left and right outputs on the back your solution would be to get a good power amp in a range that would provide the power you want at 8 ohms.

I'd make sure the SM-500 is broke before I tried to fix it. If the problem is caused by speakers that are out of polarity then all that's to be gained by putting more power into the equation is a the likelihood of blowing speakers.

[Denny Coon]

Thank you all!!! Any suggestions after checking all of the afore mentioned on a good priced power amp? How many watts should I look for, and suggested models? I'm gonna try the rest at practice tonight, but if I have to go further any ideas??

[Clark Dark]

It's a SWR thing. With the separate outputs the OP is getting 250 W to each cab..Anemic under certain situations. He bridges he gets a higher output but not the full range he seeks. He never said anything in his op other than he hears the loss of power when he runs dual output. And I believe his cabs are rated at 8 ohms. So I suggest if his quest is for more power to the cabs while still using the dual outputs, simply get a power amp that will give him the wattage he seeks @ 8 ohms. My Mo'Bass is anemic too when I use the dual outputs.

[Zooberwerx]

Originally Posted by Denny Coon

Thank you all!!! Any suggestions after checking all of the afore mentioned on a good priced power amp? How many watts should I look for, and suggested models? I'm gonna try the rest at practice tonight, but if I have to go further any ideas??

You need to check all systems as described previously then get back to us. Snap a pic of the cabling config. if you have to.

Riis

[Alex1984]

I'd still just say don't bi-amp. Bi-amping is more suitable for PA situations where you have subs and mid/top boxes, most bass cabs are full-range. Running the 2 cabs together using the bridge mono banana plugs would be much better. While there are many benefits in bi-amping a PA setup, bass rigs don't really benefit from it. Even the few manufacturers that build crossovers into their amps (like GK) normally would build them to separate tweeter from the woofer.

Especially in cases like this where the sensitivity of the 410 is likely much greater than that of the 115. In a sense, you're getting a sensitive cab to produce signals that are already more audible, and telling a less sensitive cab to produce signals that are less audible, you'd get a lot more if you just got them to both produce the full range. Also, 210s and 115s are a much better match sensitivity-wise but many would argue that you should ditch the 115 and run 2 410s.

Bottom line, IMO, don't run bi-amp, and if you really feel you have to, get cabs with better matching sensitivity ratings.

[Zooberwerx]

Originally Posted by Alex1984

I'd still just say don't bi-amp. Bi-amping is more suitable for PA situations where you have subs and mid/top boxes, most bass cabs are full-range. Running the 2 cabs together using the bridge mono banana plugs would be much better. While there are many benefits in bi-amping a PA setup, bass rigs don't really benefit from it. Even the few manufacturers that build crossovers into their amps (like GK) normally would build them to separate tweeter from the woofer.

Especially in cases like this where the sensitivity of the 410 is likely much greater than that of the 115. In a sense, you're getting a sensitive cab to produce signals that are already more audible, and telling a less sensitive cab to produce signals that are less audible, you'd get a lot more if you just got them to both produce the full range. Also, 210s and 115s are a much better match sensitivity-wise but many would argue that you should ditch the 115 and run 2 410s.

Bottom line, IMO, don't run bi-amp, and if you really feel you have to, get cabs with better matching sensitivity ratings.

False alarm. Turns out the OP is running the amp in stereo / dual mono, not bi-amped as initially stated.

Riis

[Alex1984]

Cool, SWR removed that built-in crossover thing that was originally on the SM-400.

By the way, many people have commented before that, running in bridge mono really "wakes up" the amp.

Mathematically, you'll be getting 500W, bridged mono @ 4 ohms vs. 150W per side, stereo @ 8 ohms. So you'll definitely get an audible increase in power. However, be sure you allow the amp to cool properly, and I wouldn't push it to MAX.

[BassmanPaul]

Originally Posted by billfitzmaurice

I'd make sure the SM-500 is broke before I tried to fix it. If the problem is caused by speakers that are out of polarity then all that's to be gained by putting more power into the equation is a the likelihood of blowing speakers.

Another possibility is the amp is in bridge mode which would cause the same thing.

[billfitzmaurice]

Originally Posted by Alex1984

Mathematically, you'll be getting 500W, bridged mono @ 4 ohms vs. 150W per side, stereo @ 8 ohms. So you'll definitely get an audible increase in power.

150w per side into 8 ohms is 300 watts into two cabs, versus 500w into the same two cabs when bridged. That's about a 2dB increase, which is barely audible, if at all.
Assumptions made about how much louder any rig will go if more power is output are almost always based on the notion that loudness is linear with respect to power. It isn't. And that's why quests to 'get all the watts out of my amp' are usually fruitless.

[Alex1984]

Yeah, I know it's 300W vs. 500W and I do realize volume is not linear w/ power, I'm just pointing out that, in terms of sheer electrical power, he'll be gaining more. And most of the time, I found that an increase of 3dBs is quite audible.