Follow up to my PA Mains thread

Les

Well-Known Member
I had posted this as a follow-up in my earlier thread, but moved it to its own thread in hopes of receiving more exposure.

Since my last posting, I have strayed away from the Peavey PR series. I saw them in Guitar Center and they just have a cheap look and feel.

Right now, I have two QSC GX3 amps ready to feed whatever speakers I finally decide on. Here are some of the specs of the amps:

8 ohms / 1 kHz (both channels driven) 300 W
8 ohms / 1 kHz (single channel driven) 350 W
4 ohms / 1 kHz (both channels driven) 425 W
4 ohms / 1 kHz (single channel driven) 500 W

The speakers I have narrowed it down to are as follows:

Mains

Yamaha S112V

-Woofer: 12 in.
-Tweeter (diaphragm): 2 in. titanium
-Freq Resp (-10dB): 60Hz-16kHz
-Impedance: 8 Ohm
-Power Handling (noise1/program/peak): 175/350/700
-Sensitivity: 97dB
-Max. SPL3: 126dB

--OR--

JBL JRX112

-Frequency Range (-10dB): 60Hz - 16kHz
-Frequency Response: (3dB): 70Hz - 12kHz
-Sensitivity (1W/1m): 99dB SPL
-Nominal Impedance: 8 Ohms
-Power Capacity (continuous, 100-hour power test): 250 Watts
-Peak Power Capacity: 1000 Watts
-Recommended Amplifier Power: 250 Watts to 500 Watts into 8 Ohms
-Maximum SPL: 129dB
-Nominal Dispersion: 90 degrees x 50 degrees
-Crossover Frequency: 1.8kHz
-High Frequency Driver: JBL 2412 1 in. exit compression driver mounted on Progressive Transition Waveguide
-Low Frequency Driver: JBL M112-8

It seems that the universal opinion on the Yamaha's is that I could do better. Would the JBL's be the ticket? I really need to stay within this price and size range.

The subwoofer I am looking at is the JBL JRX118S. (I'll just be using a single sub in the foreseeable future.)

-Frequency range (-10dB): 38Hz - 300Hz
-Frequency response (±3dB): 55Hz - 300Hz
-Sensitivity (1w/1m): 96dB SPL
-Nominal impedance: 4 ohms
-Power capacity: 350W continuous, 1400W peak
-Maximum SPL: 127dB
**This sub will have its own GX3 (in crossover mode) devoted to feeding it**

I am also considering purchasing two Yamaha MSR100's. The idea is that they can provide fill for larger ballroom type events. I can place them toward the back of the room near the tables for background music (BGM) during receptions, etc. They really won't be used for dance music or anything like that. I would connect them to the main mixer via monitor out. They could also come along on small events (50-100 people in a community center) as the principal sound system. I play keyboard as well, and they would make great monitors or "coffee shop mains". They are only 8", and I might spring for the 10's, but I don't think it will be necessary for my uses.



And just for kicks, the mixer I am considering is the Yamaha MG124CX. I don't need a lot of functionality since I'm only doing music playback with a few mics for emcees. I just need something that will get the job done. I was considering the A&H ZED-14, but somehow I landed on this instead. Probably something to do with the price ;-).

As for cases, I will probably split it up. The amps will go in a 4 or 6U case and go on the floor, while the signal processing gear (EQ, CD Player, Juice Goose, Wireless Mics, etc) will go in a separate 4-6U case and sit on a table. For the amp case, should I go with a 4U and be all compact, or should I do a 6U and allow some air space and possibly room for a second power conditioner?


As always, if you guys have any additional words of wisdom, fair warnings or just general comments and input I'd love to hear it!
 

bishopthomas

Well-Known Member
We have 14 of the JRX 112m's (looking at buying 2-4 more soon) and they have worked out very well for us. They typically are used as the B rig monitors but often double as SOS, fills, etc. When we first started buying them they were replacing Yamaha SM115IV's. As far as mixer choice goes, the Yamaha is decent if it fits your needs. I have the MG410/2 and use it whenever I only need a few channels in a briefcase size case. Keep in mind the MG124 only has 6 preamps, not a full 12 channels for microphone inputs.

For cases, I am a fan of wheels. It all depends on how you're transporting the gear, but I would say put the amp rack on wheels (probably 6U) and you can stack the FOH rack on it to roll in. Keep in mind the more cases you have the more you'll have to carry in and interface. The trade off is that you'll actually be able to carry it yourself, rather than one big heavy (and prewired) rack. Rack panels are your friends in this circumstance. If you decide to go with I/O panels let me know if you need any help. You pay for the materials and I'll do the build out. Custom racks and cabling is a service I'm going to be pushing hard in the new year and I wouldn't mind having some new photos I can put on the (soon to be new) web site.
 

DuckJordan

Well-Known Member
Personally I would go for the Yamaha's, I've been around the full range of Yamaha equipment from motorcycles to PA's and never had reliability issues with anything. That said, The most experience I've had with JBL's is they are a big speaker name but i've had to work with 5 of them all had some sort of issue.

So with Yamaha you pay for quality, while JBL's i feel you pay for the name.
 

bishopthomas

Well-Known Member
I'm not sure what motorcycles have to do with speakers... My experience with JBL has been exactly opposite of yours. JBL pours money into R&D and has product lines for every budget (from JRX up to Vertec). Yamaha has only low end MI speakers.
 

TimmyP1955

Well-Known Member
I'm not sure what motorcycles have to do with speakers... My experience with JBL has been exactly opposite of yours. JBL pours money into R&D and has product lines for every budget (from JRX up to Vertec). Yamaha has only low end MI speakers.

Yes, but JBL has made a few dogs over the years. A while back it was the TR series. These days, many don't care for the JRX.

The specs tell you nothing about how they will sound, or how loud they will go while still being listenable. One must audition them for himself.
 

bishopthomas

Well-Known Member
TimmyP1955 said:
Yes, but JBL has made a few dogs over the years. A while back it was the TR series. These days, many don't care for the JRX.

I certainly understand and agree with that. Sure, many don't like the JRX, but they're the bottom of the line range and for the money I don't think they can be beaten.

TimmyP1955 said:
The specs tell you nothing about how they will sound, or how loud they will go while still being listenable. One must audition them for himself.

You said it!
 

Les

Well-Known Member
Thanks all for your help so far!

So I went in to Guitar Center today and it raised more questions than answers. I went in looking for the JRX112M's (and found them) but the JRX115's also caught my eye.

Both the JRX112 and the 115's both (oddly) state the same power requirements: 250w continuous, 1,000w peak. The salesman said that I'd need a bigger amp than the GX3 to power the 112's and a way bigger amp to handle the 115's. He gave me the whole spiel about damaging speakers by under powering them, etc.

What I would like to do is have two JRX115's for the mains, and two JRX112's for fills (and monitors if I ever do small shows). I have the two QSC GX3's with the following specs:

8 ohms / 1 kHz (both channels driven) 300 W
8 ohms / 1 kHz (single channel driven) 350 W
4 ohms / 1 kHz (both channels driven) 425 W
4 ohms / 1 kHz (single channel driven) 500 W

So, can I use a GX3 to power a pair of JRX112M's? Seems like it shouldn't be a problem, especially for fills.

How about the JRX115's? I realize that upgrading would be a good idea, but do I NEED to? How much of an upgrade? The salesman of course recommended an 800w per channel Crown amp at $599. Well, why not a GX5 or a GX7?

I hope you guys can help clarify this for me!

For the record, I used my GX3 to power a pair of Peavey SP2XT speakers, each rated at 600w program. Sounded great, and I really don't think I "hurt" them any. I clipped the amp once on the Cupid Shuffle, and that was my own fault.
 

DuckJordan

Well-Known Member
Thanks all for your help so far!

So I went in to Guitar Center today and it raised more questions than answers. I went in looking for the JRX112M's (and found them) but the JRX115's also caught my eye.

Both the JRX112 and the 115's both (oddly) state the same power requirements: 250w continuous, 1,000w peak. The salesman said that I'd need a bigger amp than the GX3 to power the 112's and a way bigger amp to handle the 115's. He gave me the whole spiel about damaging speakers by under powering them, etc.

What I would like to do is have two JRX115's for the mains, and two JRX112's for fills (and monitors if I ever do small shows). I have the two QSC GX3's with the following specs:

8 ohms / 1 kHz (both channels driven) 300 W
8 ohms / 1 kHz (single channel driven) 350 W
4 ohms / 1 kHz (both channels driven) 425 W
4 ohms / 1 kHz (single channel driven) 500 W

So, can I use a GX3 to power a pair of JRX112M's? Seems like it shouldn't be a problem, especially for fills.

How about the JRX115's? I realize that upgrading would be a good idea, but do I NEED to? How much of an upgrade? The salesman of course recommended an 800w per channel Crown amp at $599. Well, why not a GX5 or a GX7?

I hope you guys can help clarify this for me!

For the record, I used my GX3 to power a pair of Peavey SP2XT speakers, each rated at 600w program. Sounded great, and I really don't think I "hurt" them any. I clipped the amp once on the Cupid Shuffle, and that was my own fault.

Okay first off, under-powering speakers will never damage them. This is reason 1 not to buy things from guitar center. 2. the only time i use guitar center is to buy maybe a random cable or two, or possibly get a trial of a speaker that they have at the time that my normal place doesn't carry but will order for me.

My suggestion is to go talk to an actual dealer not guitar center and ask them about it they are less likely to sell you something you don't need because they are worried about keeping their jobs, most guitar center guys move through and out within a year so not so worried about job stability.
 

bishopthomas

Well-Known Member
Les, the GX3 would work with the pair of JRX112m's, but only if you dedicate the entire amp to both speakers. If you wanted to run both mains off one side of the amp and both fills off the other that's when you would need to step up to a larger amp. Of course, then you're losing your stereo separation, so I'm not sure if you're looking to run your rig in mono. As far as 112 vs 115: I'm a fan of 12's for tops, but only when used with subs. I would say that you most definitely want subs if you're doing dance music, with any tops you buy, but especially with 12's (and especially with the JRX's as they do not have the sensitivity or power handling to produce the low end that you're going to want for this type of gig).
 

jeffsw6

Member
Since my last posting, I have strayed away from the Peavey PR series. I saw them in Guitar Center and they just have a cheap look and feel.
Those things are terrible, I am glad you decided not to invest money in them!

It seems that the universal opinion on the Yamaha's is that I could do better. Would the JBL's be the ticket? I really need to stay within this price and size range.
You certainly could do better, these are entry-level speakers. Since that is what you want and are limited to by your budget, honestly, I think these are okay speakers for the price. I would not suggest using them to provide to other bands/DJs/whatever unless it is absolutely bottom-of-the-barrel work, though. The JBL MRX series is a big step up in quality and value for a moderate step up in price.

The subwoofer I am looking at is the JBL JRX118S. (I'll just be using a single sub in the foreseeable future.)
Junk. :( What is your total budget? How badly do you want the MSR100s for fill vs want a better main PA that likely will see more routine use? What is the best business choice for you, four really cheap PA speakers, two of which will often stay in the shop; or two better ones?

I am also considering purchasing two Yamaha MSR100's.
Junk. :( See above comment/question.

As for cases, I will probably split it up. The amps will go in a 4 or 6U case and go on the floor, while the signal processing gear (EQ, CD Player, Juice Goose, Wireless Mics, etc) will go in a separate 4-6U case and sit on a table. For the amp case, should I go with a 4U and be all compact, or should I do a 6U and allow some air space and possibly room for a second power conditioner?
You should not really need "power conditioners" in your amplifier rack. Note that the Juice Goose units have basically similar technology and surge-arresting capabilities as $30 RadioShack power strips. There is nothing special there. Since you likely won't spend much time using the convenience receptacles or lights that are usually built-in to rack mount PDUs, I suggest you don't buy one for your amp rack.

I do suggest you get a rack that has enough room for some other items:
* 1U DSP, like a DriveRack
* patch panel, which might go right behind your driverack?
* some empty space inside the rack for stowing a fan-to-fan snake that connects the amp rack to your other rack or your main snake, this will save you some time at every gig and reduce patch mistakes

You could not be more wrong. Under powering them causes WAY more damage than over powering them. Do a Google search for "speaker, amp, power, square wave."
To expand on this a bit, there are basically three modes of speaker damage the OP should be made aware of so he can operate his new gear safely AND avoid bad advice from the Guitar Center dude:
1) thermal damage from too much long-term power
2) over-excursion damage from too much LF content, a common damage mode for subwoofers and woofers but usually not for mid- and hf-drivers in "full-range" speakers that include passive crossover networks
3) thermal damage to HF drivers from "clipping" (wave deformation) shifting energy to the HF drivers, in the form of distortion

You may not notice #1 until it's too late, but this doesn't honestly happen very often because "most" program material has a large enough crest factor that, unless you were using a compressor/limiter on the mix with misguided settings, you would encounter a different failure mode first.

#2 is somewhat easy to avoid if you know what your speakers sound like when the cones are beginning to "flap" or "bottom out." If you have a DSP with a high-pass filter, and set it appropriately, you probably will not break your speakers this way.

#3 is what the red light on the amplifiers is telling you to avoid. "Clipping" generally will cause thermal damage to the highest-frequency driver in the system, e.g. the HF horn driver. In a relatively sane configuration, that red clip light can blink pretty often with no permanent damage. You should be able to hear the speakers starting to sound bad from amplifier output distortion long before you actually wreck any speaker components. That "sounds bad" is a warning to turn something down.

Note that damage mode #3 can also be caused by clipping at earlier points in the signal chain. If you want to fry a HF driver really quick, take a DJ mixer with a +26dBu output, hook it into a mix console with the pre-amp gain all the way up, and route that trash signal to your speakers. They will sound bad immediately and your HF drivers will probably fail pretty fast, even if you do not turn the amplifier up far enough to make the red light blink.

So to avoid #3, don't let things in your line-level processing chain clip heavily, don't let the amplifier clip heavily, and if it sounds like you don't have "enough rig for the gig" and the speakers are straining, always remember, mixing -3dB quieter is better than frying your speakers and ending the night early.

As far as 112 vs 115: I'm a fan of 12's for tops...
Another topic that can be very, very in-depth. I agree with bishopthomas that the CM12V and JRX112M are better-sounding PA speakers, when used with subwoofers, than their 15" counterparts. I have a totally different opinion about other lines of speakers from JBL, and my opinion varies by application, too. Further, if I needed more output than a CM12V can deliver and a C215V was my other choice, I would take the C215V.

This is a complicated question, and the best way to figure out the best answer for yourself is to think hard about how to spend your budget, and listen to some speakers at gig volume. Don't be afraid to rent some speakers for a day if you can't demo them really loud at the GC retail location! Check out other bands/DJs/sound providers near you and see how their various rigs sound. Every speaker sounds great on paper. :)
 

museav

CBMod
CB Mods
Departed Member
You could not be more wrong. Under powering them causes WAY more damage than over powering them. Do a Google search for "speaker, amp, power, square wave."
You can't 'under power' a speaker, however you can have an insufficiently powered system for an application and that can indeed lead to damaging the speakers. As Jeffsw6 explained, there is more than one way to damage a speaker with some being associated with having too small an amplifier for the application and others with having too much amp for the application. What defines the "application" can include the output levels one is trying to get, the signal characteristics (especially issues such as crest factor), the system operator (I've seen operators who seemed to think the clip lights were signal presence indicators and had to be lit at all times) and other aspects.

A good protection system will include both peak limiting to address signal peaks and RMS or average limiting to address longer term levels and to maintain some headroom in the system.

I do have to disagree with Jeffsw6 a bit in terms of long term thermal failures based on the feedback I've received this is probably the most common failure mode and has become increasingly common due to two likely causes. One is that the wider availability and application of system processors has lead to peak limiting being more common in systems, which can help in terms of overexcursion and amp clipping. The other is the practice of compressing a signal to make it 'louder' without increasing the peak levels, leading to higher average levels and lower crest factors.
 
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jeffsw6

Member
One is that the wider availability and application of system processors has lead to peak limiting being more common in systems, which can help in terms of overexcursion and amp clipping. The other is the practice of compressing a signal to make it 'louder' without increasing the peak levels, leading to higher average levels and lower crest factors.
That's why I qualified my remark by also saying ... "most" program material has a large enough crest factorhttp://www.controlbooth.com/wiki/Crest+Factor that, unless you were using a compressor/limiter on the mix with misguided settings...

I don't know how to explain that to someone with only entry-level knowledge, and if the OP already has more than entry-level knowledge, he will already understand and not need further explanation. :)

It may also be worth mentioning that the latest generation of bi-amplified powered loudspeakers include DSP that is sophisticated enough to prevent damage through any of these means. The latest and greatest boxes from JBL and QSC are, in my opinion, "DJ proof." IMO this makes them especially valuable for rentals and other situations where the operator may not be knowledgeable or careful enough to keep the system within its safe limits.
 

museav

CBMod
CB Mods
Departed Member
It may also be worth mentioning that the latest generation of bi-amplified powered loudspeakers include DSP that is sophisticated enough to prevent damage through any of these means. The latest and greatest boxes from JBL and QSC are, in my opinion, "DJ proof." IMO this makes them especially valuable for rentals and other situations where the operator may not be knowledgeable or careful enough to keep the system within its safe limits.
I forget which of the powered speakers it was, I think one of the QSC models, that has something like 20 different limiters in it providing peak and average limiting for different frequency bands. This approach let's them maximize the performance, especially the output, possible while still providing protection.
 

Les

Well-Known Member
Thank you all for your valuable feedback. It is very much appreciated! I have decided to go ahead and do a pair of JRX112M's so I don't have to turn down any small wedding gigs in the interim, while setting my sights, ultimately, a nice set of QSC powered boxes. I will also be looking for a nice powered sub to go with the JBL's for now, while (hopefully) eventually complementing the QSC's.

Once I have the nice boxes nailed down (probably a good year from now), the JBL's will become monitors/fill for larger events or SOS mains for very small events.
 

jeffsw6

Member
...so I don't have to turn down any small wedding gigs in the interim
Don't forget that you can rent more/bigger speakers if you have not-small wedding gigs come your way. If your pricing is in line with typical DJ or sound reinforcement rates for weddings, which are way inflated (for good reason) compared to many other kinds of events, renting speakers for these gigs is very economical. I have ~150 gigs a year that require PA, so it makes a lot of sense for me to own; but I still sometimes rent when the needs of a job exceed my inventory.
 

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