Members drumstix Posted July 20, 2006 Members Share Posted July 20, 2006 Hello, quick question about 2 amps, the first being an RMX1850 and the other is the Yamaha 5000. The new amp will power up 2 subs, will be bridged mono and 1800w (RMX) and 2000w (5000-something) respectfully. The subs are rated at 800w @800ohms each so the power is in the ball park. Question is, is either one of these amps a better choice for its new task? There both about the same price, but the Yamie is way lighter and is the amp I would like to try first and one reason is the almost 20 pounds of lower mass. Is the Yamaha a good sub amp? I know from past readings that the RMX is a solid amp. Thanks, Bob Link to comment Share on other sites More sharing options...
Members Marko Posted July 20, 2006 Members Share Posted July 20, 2006 Originally posted by drumstix Hello, quick question about 2 amps, the first being an RMX1850 and the other is the Yamaha 5000. The new amp will power up 2 subs, will be bridged mono and 1800w (RMX) and 2000w (5000-something) respectfully. The subs are rated at 800w @800ohms each so the power is in the ball park. Question is, is either one of these amps a better choice for its new task? There both about the same price, but the Yamie is way lighter and is the amp I would like to try first and one reason is the almost 20 pounds of lower mass. Is the Yamaha a good sub amp? I know from past readings that the RMX is a solid amp. Thanks, Bob May I ask out of curiosity what subs you've got? I'm assuming they're single-driver, being they're 8ohms each. That may be a lot of watts. There may be some more advice for you concerning this combo. Link to comment Share on other sites More sharing options...
Members Al Poulin Posted July 20, 2006 Members Share Posted July 20, 2006 Both are excellent amps from reputable companies. The Yamaha P5000 is best used with stereo 8ohm and 4Ohm loads or 8ohm loads when bridged. Ignore the specs you see on the box. This amp is not meant to do 2ohms per channel stereo or 4ohms bridged. I'm not familiar with the QSC's specs but am almost sure it is better than the Yamaha for bridge mode sub operation. You might, however want to consider a Yamaha P7000 or more powerful QSC model and run it in stereo with one sub per channel. This will be much better for the amp and it will make sure your investment lasts you much longer. Bridging in general is hard on an amplifier and the small gain in volume it might achieve is not worth the stress on the components - both speaker and amplifier IMO. Best of luck, Al Poulin - Party-Time! DJ Services Link to comment Share on other sites More sharing options...
Members drumstix Posted July 20, 2006 Author Members Share Posted July 20, 2006 Sorry about that. The subs are 2 JBL SRX718s, rated at 800w running @ 8ohms. Im debating about a replacement set. My tops are 2 U15's running stereo on a single PLX3402. Actually I even got the Yamaha's wrong. The P5000 is claimed to put out 2600w @ 4 ohms, that would be 1300w in each speaker. THe P3500 is the amp that puts out 2000w @ 4 ohms. These are bridged 4 ohm specs. The RMX1850 is 1800w. I would rather yet run a PLX in stereo mode but seems that the majority here says a PLX isnt a good sub amp. Thanks for the help, Bob Link to comment Share on other sites More sharing options...
Members Marko Posted July 20, 2006 Members Share Posted July 20, 2006 Oh... that's different. Those are 800watts RMS/continuous, 3200watts Peak. Someone said the PLX isn't a good amp for subs? Not too many in the room right now. I'm sure you'll get plenty of good advice in a bit. Link to comment Share on other sites More sharing options...
Members Al Poulin Posted July 20, 2006 Members Share Posted July 20, 2006 Originally posted by drumstix The P5000 is claimed to put out 2600w @ 4 ohms, that would be 1300w in each speaker. Thanks for the help, Bob This spec is not represtentative of real world performance and is put on the box simply to impress buyers. It is measured in 20 microsecond bursts and there is no way this amp can produce this much output continuously. Real world specs are 525 watts/channel at 8ohm, 750 watts /channel at 4ohm or 1500 watts bridged into 8ohm load. Yamaha gives numbers for 4ohm bridged load and 2ohm stereo load but then tells the user not to use the amp at these impedances....it is a numbers game. The Yamahas are awesome performers, I loved my P5000s, but these specs are very misleading. Al Poulin - Party-Time! DJ Services Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 20, 2006 CMS Author Share Posted July 20, 2006 The PLX work fine for subs. I know Mr.Knobs and Dan (Audioeast) hate it for subs, but I power a pair of SR4719X with one, and I dare anyone to tell me they don't work great. I take a dim view of both bridging and of overpowering subs significantly. Doing both is worse IMO...the chances of a problem turning into a disaster are multiplied. The JBL's can indeed be a challenge to power...800+ watts @ 8ohms is tough to provide with a single amp channel. You say this is an additional purchase, so we can assume you already have a pair, and you've got a PLX3402. Try running a set on that amp, one per channel, and decide how they perform. If a set of speakers don't do well when powered at or near their rated continuous power, that's a strong indication that you need more speaker, not just more power. Link to comment Share on other sites More sharing options...
Members Ear Abuser Posted July 20, 2006 Members Share Posted July 20, 2006 The Yamaha is a lighter amp. Also, I believe it will draw less AC current than the RMX, both big pluses in my book.Nothing wrong with the RMX though. Link to comment Share on other sites More sharing options...
Members The Real MC Posted July 20, 2006 Members Share Posted July 20, 2006 800 watts for a sub? CONTINUOUS? Sheesh, I have 400w subs (EV S-181s) and they are overkill for most clubs. Are you doing outdoor gigs or large halls with these subs? That's a LOT of power. Link to comment Share on other sites More sharing options...
Members Gregidon Posted July 20, 2006 Members Share Posted July 20, 2006 So, not to steal this thread.... but why do some people not like the PLX for subs? I ask since i'm looking at getting on to power my bass rig....-greg- Link to comment Share on other sites More sharing options...
Members dboomer Posted July 20, 2006 Members Share Posted July 20, 2006 Originally posted by The Real MC 800 watts for a sub? CONTINUOUS?Sheesh, I have 400w subs (EV S-181s) and they are overkill for most clubs. It's not like doubling the available power is going to make the subs much louder. It's only a mere 3 dB difference. I agree with Craig ... run the amp you have in stereo. Remember that power rating of 800W in thermal (midband). Those speakers will probably handle 1/4 to 1/2 of that power down at 40 Hz. Link to comment Share on other sites More sharing options...
Members DaBender Posted July 20, 2006 Members Share Posted July 20, 2006 QSC seems to recommend the "2 series" units for bass. From their literature - 2 ways to get PLX2 performanceThe "02" models (PLX1802, PLX2502, PLX3102 and PLX3602) are the right choice for users who need to drive up to four loudspeakers from each amplifier channel (2 ohm loading), or when extremely high power bridge mono operation is required. These models feature built-in subwoofer processing, filter switches, and front panel indications of bridge mono status. The compact "04" models (PLX1104, PLX1804) bring the same performance and technology, plus even greater value, to applications that don't require bridged or 2 ohm operation. Designed to power 1 or 2 speakers from each amplifier channel (4 ohm minimum loading), these models offer a simplified feature set while retaining genuine, uncompromised PLX performance and technology. Weighing just 13 pounds (5.9 kg) these "plug-and-play" amplifiers are perfect for ultra-portable rigs, as well as reference-quality playback. Link to comment Share on other sites More sharing options...
Members The Real MC Posted July 20, 2006 Members Share Posted July 20, 2006 Originally posted by dboomer It's not like doubling the available power is going to make the subs much louder. It's only a mere 3 dB difference. True in electronics and pro audio, but not in sound reinforcement. You're forgetting the SPL spec. Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 20, 2006 Members Share Posted July 20, 2006 Originally posted by The Real MC True in electronics and pro audio, but not in sound reinforcement. You're forgetting the SPL spec. Huh? Not sure what you mean. Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 20, 2006 Members Share Posted July 20, 2006 I've run both linear and SMPS supply power amps on subs and I have not been able to quantify any realstic difference worth worrying about. I've also designed amplifiers with both kinds of power supplies and there 's no realistic difference in sound quality within the limits of each product. My first suggestion is to try the subs in stereo on the 3402, that's not using the full potential of the driver but is within about 2 dB of full potential. remember that increasing the average power increases thermal load and thus thermal compressiion reducing gain from theoretical to a lesser factor. The reliability curve starts getting pretty steep while the increase in SPL is pretty minimal. You would get a much higher return of performance by adding a second identical box to each side operated off the same PLX-3402. (maybe +5-6dB net SPL) while dramatically improving the lifespan of the drivers... maybe by a factor of 5 or more. As far as the Yamaha's 20mSec rating, that's find for mid & high freq. transients but for low freq transient burst power ratings I use 200mSec personally since the period of a low frequency waveform is inversely proportional to frequency. Also note that below a cabinet's cutoff freq, the sub driver will unload and the mechanical power handling decreases very, very quickly. Link to comment Share on other sites More sharing options...
Members dboomer Posted July 20, 2006 Members Share Posted July 20, 2006 Originally posted by The Real MC True in electronics and pro audio, but not in sound reinforcement. You're forgetting the SPL spec. ?? Please explain ?? Link to comment Share on other sites More sharing options...
Members Unalaska Posted July 20, 2006 Members Share Posted July 20, 2006 Since you have the PLX for tops I'd recommend the 3402 in stereo on subs. It'll be great when you get the second pair of subs too. The P7000 in stereo would be my next choice especially since it has a variable HPF and the wieght is nice. An RMX1850 bridged would be a good choice but limit your options if you get mo' speakers. FWIW, I swear by the P7000 and P5000 running 2ohms on sub duty. I've done it quite a few times and will continue to as needed. For some reason the amp seems to open up with 4 and 2 ohm loads, I don't know why or how to explain it but it does. Anyway, take it for what it's worth. The PLX3402 is my vote in stereo... Link to comment Share on other sites More sharing options...
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