Sub and amp

[troyri]

Currently using the subs below (8ohm) until tax time. I know they aren't the greatest but the specs aren't bad (imo). We are running them off of a Behringer EP2500 (I think this is the weak link). Questions is would a QSC RMX 2450 (which the Behringer is a copy of) run them better? From what I read here the B probably isn't putting out the wattage it says. We just need some more volume to keep up with the NX55P's. The amp will be moved to monitor duty when the new subs are purchased. If not the 2450 which amp would you recommend?

 

 

 

 

 

http://wharfedalepro.com/Home/Products/CLASSICPRODUCTS/LXLXESERIES/LX18MBLX18MBE/tabid/114/Default.aspx

[GCDEF]

The Behringer claims to put out 2400 watts bridged into 4 ohms. If you're not running bridged now, you could try that and see if it help. I doubt the QSC would give you significantly more volume.

[troyri]

Tried that last weekend. And of course the amp overheated and thermaled.

[tlbonehead]

I wouldn't put more than about 600 watts into them. I see there is a 4 and 8 ohm version. So whichever amp gives you 500-650 RMS at the impedance of the model you have. If that isn't enough volume you need more speaker, not just more horsepower.

[agedhorse]

First of all, I have questions about your implimentation of bridged mode... how you didn't destroy your speakers is a miracle. The Behringer 2500 generally delivers pretty close to it's rated power (where did you read otherwise?), the bigger issue is under highly reactive loads and reliablity. EXACTLY how did you connect to the output termonals of the amp???

 

The new Behringer amps are not rated the same as the older ones, they now use peak power, but when making the math conversion they deliver close to their (converted) rated power. 2000 watts peak = 1000 watts RMS.

 

IMO, the limitation in your system is the speakers and not your amp, they are pretty well matched to the 2500 in stereo mode. You might be better off getting another pair of exactly the same subs and run 2 subs per channel.

[troyri]

It is an older ep2500. I may not have read that the 2500 doesn't put out its advertised ratings, I probably just associated the word Behringer with lies and fake claims as this site has kinda lead me to believe. I ran a banana cable from the middle 2 post and daisy chained the 2 - 8ohm speakers. I did have the limiters on and the 50hpf. The amp wasn't clipping, matter a fact the signals lights were just flickering so I don't think I was running the amp hard (probably why I didn't blow the speakers I guess). When I run it in stereo, the clip lights flicker on the amp so I figured I would get a little more out of it by bridging it. I didn't plan on running it full tilt or anything, I just wanted a little more. The amp was very hot to the touch and shutdown. I changed everything back and went the rest of the night in stereo without any problems. I am getting new subs come tax time I was just trying to get by on these for a couple of months, but at a few venues I seem to need a little more bottom end so I was going to get it from the amp. As I read, these subs should keep up with my NX55P if properly powered, So am I to believe that my speakers not really what they say they are? 800 cont, etc.

[tlbonehead]

.

That's the best bet. You already have an amp that will suitably support/power 1 or 2 sets of the subs. This gives the user the modular flexibility to use what is needed for different sized gigs/venues.

[agedhorse]

Ok, you get bonus points for correct output connections in bridge mode. You DON"T want to use bridge mode with your speakers though.

 

Double-check that your speakers are not 4 ohms each and maybe mislabeled. Just a hunch (especially since the signal LEDs were just flickering). How long did it take for your amp to thermal?

 

No way the subs are 800 watts continuous. I would guess 400 watts continuous and 800 watts program on a good day. Good match for the 2500 in stereo mode.

 

Another thing to check is that you do not have a cross-wired (reversed polarity) speaker cable, and possibly that even one of your cabinets is improperly wired.

 

Use a 9 volt battery and with a speaker cable plugged into the first cabinet and then another from the first to second cabinet, apply the + terminal of the battery to the 1/4" plug tip and the - terminal of the battery to the sleeve. Both speakers should bove outward when you momentarily connect the circuit. (amp is not connected, this just tests the speaker wiring and speakers.

 

Also, you are switching the amp back to stereo mode when running in stereo right? Bridge mode inverts the polarity of channel 2 on the amp which is why the speaker connections are the way they are in bridge mode.

[troyri]

I did switch it back to stereo. Hadn't thought about them being reverse polarity though. I'll check the ohmage with my meter later. Thanks for the reply's. The speakers do sound nice an punchy, its a shame that they don't do what they say they will. Live and learn I guess, I just bought these for 400.00/pair because our old ones were old school PV's that were rated at 150 watts and they didn't have a chance with the Yorkvilles over them. I can get another set just like them for another 400. But like I said I was planning on new ones with tax money. I do understand the flexibility of having 2 sets though so. You guys are the pros here. If I was buying I would most likely buy the Yorkville 720P just to keep them matched. Do you think I would be better of just buying another set of what I have and saving some cash? I don't want to sacrifice sound though.

[tlbonehead]

I did switch it back to stereo. Hadn't thought about them being reverse polarity though. I'll check the ohmage with my meter later. Thanks for the reply's. The speakers do sound nice an punchy, its a shame that they don't do what they say they will. Live and learn I guess, I just bought these for 400.00/pair because our old ones were old school PV's that were rated at 150 watts and they didn't have a chance with the Yorkvilles over them. I can get another set just like them for another 400. But like I said I was planning on new ones with tax money. I do understand the flexibility of having 2 sets though so. You guys are the pros here. If I was buying I would most likely buy the Yorkville 720P just to keep them matched. Do you think I would be better of just buying another set of what I have and saving some cash? I don't want to sacrifice sound though.

what won't they do that they say they will do? Not really getting your comment there. As for the 720 comment, I'm sure a pair of these with 600 watts into them will easily do what a pair of Yorkie 720s will do.

[troyri]

Doesn't seem that they will handle the power they say, according to you guys. Which is fine, I should have asked here before I jumped on them. Their plywood instead of MDF and had pretty good specs so I didn't bother. I really just saw the 134db and the 800 cont. and figured I was good to go. If these will keep up with the 720's with the amp I have, I am very happy that I posted about this and I won't be wasting my money on new ones.

 

 

System FB 134dB

POWER HANDLING (Watts)

Continuous RMS 800

Program 1600

Peak 3200

[agedhorse]

The DC resistance of the driver should be between 4.5 and 6 ohms if it's a nominal 8 ohm (AC) impedance.

[tlbonehead]

Doesn't seem that they will handle the power they say, according to you guys. Which is fine, I should have asked here before I jumped on them. Their plywood instead of MDF and had pretty good specs so I didn't bother. I really just saw the 134db and the 800 cont. and figured I was good to go. If these will keep up with the 720's with the amp I have, I am very happy that I posted about this and I won't be wasting my money on new ones. System FB 134dB POWER HANDLING (Watts) Continuous RMS 800 Program 1600 Peak 3200

exaggerating is pretty much the trend these days with MOR speakers. But even if you give them their rated power (800 rms) vs 600, you might gain maybe 1db of output. Is that 1 db worth running your speakers right to the edge (possibly past)? If you use your low-cut filters and have an amp with good limiting (and engage it obviously) you can actually fatten up your lowend a little by having the limiters actually holding the peaks back a little.

[abzurd]

Something isn't adding up. Those subs should keep up fine with the NX55P's, which isn't a super high output box. I used NX550P's over ES700P subs for a few years so I have a reference. Your current setup should be capable of at least as much output as the 720P subs you're eying.

 

- Run in stereo (450W)

- The polarity check is a good suggestion

- Try engaging the 50 Hz HPF (There is also a 30 Hz HPF)

- You don't mention having a crossover. Do you? If so cross over around 100 Hz. If not, get one as that's likely a good bit of the problem.

- If you're bumping up the lows on your EQ. don't. You may think you're helping bring out the low end, but it just reduces overall output, heats up the speakers and degrades the sound overall.

- If I understand the brochure, there is a passive crossover in those (sometimes called a choke coil). These rob power and generally suck. If they were mine I'd remove them if possible and rely on an external crossover.

- I can't find much on the driver itself other than it's cast frame and supposedly 800W RMS. I'm having a hard time believing that, but it does suggest it's a fairly robust driver. I'm guessing a 3" voice coil.

[troyri]

Thanks for the reply Abzurd. I do have a crossover and I usually set it at 120hz for some reason. I'll lower it, check the polarity. Exactly how do I go about getting rid of the choke? Take the back panel off and run the wires from the speakon straight to the speaker?

[troyri]

Thank you Tlbonehead too.

[abzurd]

 

Thanks for the reply Abzurd. I do have a crossover and I usually set it at 120hz for some reason. I'll lower it, check the polarity. Exactly how do I go about getting rid of the choke?

 

 

It depends how it's in there. It could just be in line on the speaker cable or it may be a circuit board on the back of the input panel. If it's all built in nice on a panel I suppose the best thing to do would be to make another panel so you can put it back to spec later. You could also add another speakon I suppose and just disconnect the current input but leave the panel in place. This would mean cutting a hole in the cabinet for the new speakon connector. May be more trouble than you want to go through.

[troyri]

So I'll check everything this week. Last 2 questions though. I have a Crate SPA1400 that I could bridge, would it be better to run for a little more power but not over doing it? And is 400 to much for another pair of these?

[agedhorse]

Exaggerated power handling specs are the norm unfortunately. I'm sure it will handle that power for a few seconds but that doesn't help you much after that point eh?

[tlbonehead]

So I'll check everything this week. Last 2 questions though. I have a Crate SPA1400 that I could bridge, would it be better to run for a little more power but not over doing it? And is 400 to much for another pair of these?

that's a really good little gem of an amp, IMO, but I think you are much better off with the QSC because of its filters and limiters.

[heath_eld]

Aged horse and others commenting on the power specs: Is it really that bad? The manufacturer(s) claiming that the sub handles double what it really does?

 

A question i havent noticed up above (sorry if i've missed it) is what are you trying to do with these subs? What sort of music? Indoors or out? Is it the same venue every time?

 

I ask because i use the powered wharfedale a step down from that one (EVP15PB). Indoors, its ok. Gives a bit of thump. Not rock concert levels but serviceable. Generally. But there are some rooms where due to the nature of the acoustics, it does struggle. I used it outdoors last week (too lazy to bring my 4x bigger subs) and during playback music, we may as well have not bothered. I know its fairly well known that you need more sub power outdoors.

 

Also whats your mixer? Whats your kick drum mic if you're talking about live music? Those might affect what you hear to some extent. Is the kick drum tuned well? The bass? After all they're the main things that get down into that sub frequency.

[GCDEF]

 

Ok, you get bonus points for correct output connections in bridge mode. You DON"T want to use bridge mode with your speakers though.

 

 

Why not? They claim to be 8 ohms and handle 800 watts RMS, 1600 program and 3200 peak. The Behringer delivers 2400 watts into 4 ohms, or 1200 watts per speaker. Doesn't specify RMS, program or peak but whatever it is it doesn't sound unreasonable to me.

[tlbonehead]

Why not? They claim to be 8 ohms and handle 800 watts RMS, 1600 program and 3200 peak. The Behringer delivers 2400 watts into 4 ohms, or 1200 watts per speaker. Doesn't specify RMS, program or peak but whatever it is it doesn't sound unreasonable to me.

I certainly wouldn't want to feed a budget driver 1200 watts RMS.

[agedhorse]

 

Why not? They claim to be 8 ohms and handle 800 watts RMS, 1600 program and 3200 peak. The Behringer delivers 2400 watts into 4 ohms, or 1200 watts per speaker. Doesn't specify RMS, program or peak but whatever it is it doesn't sound unreasonable to me.

 

 

Because I am smart enough and experienced enough to know what is accurate and what is not. The problem is in the CLAIM. My experience says that between 400 and 600 watts RMS is just about right assuming HPF and limiting.