Live Sound & Production

[RoadRanger]

---

guitarman3001 wrote:

BTW, I was under the impression that the Yamaha Club series was fairly highly regarded in that low to mid level of gear.  When I was looking for new mains the Clubs were what everyone was telling me to look for.  Now I get one of the Club series subs and suddenly they're cheap crap?

---

The issue is that it takes a pair of their subs to keep up with each top. While that's fairly common with other brands too folks cheap out (or don't want to carry all them subs) and expect a single pair to do. Most of us try to use subs that are a step up from our tops so we can stay with a single pair of subs. Generally you want subs rated at twice the power of your tops. OTOH there are folks that insist you don't need loud subs so YMMV  . IME a pair of either the Yamaha's or Peavey's will just barely keep up with a pair of 200wrms rated tops. I've used PR10's (passive) and PR12D's (active) over those PV118's.

Oh, and "it depends(tm)"  .

[agedhorse]

For what you were willing or able to spend, it's the best option. It's likely that you didn't understand that the best option was not adequate to your expectations

I agree with don that quality powered speakers (not cheap powered speakers) are your best bet.

[guitarman3001]

---

agedhorse wrote:
For what you were willing or able to spend, it's the best option. It's likely that you didn't understand that the best option was not adequate to your expectations

I agree with don that quality powered speakers (not cheap powered speakers) are your best bet.

---

I think it'll meet my expectations.  We were managing ok with the single Peavey sub but needed something to beef up the low end a little bit and give us a more balanced sound throughout the entire room rather than having the bass be significantly stronger on one side of the room, which is what was happening with the single sub.  The additional sub should suit our needs ok.  My biggest question was just what's the best way to power them and if running them with 725W each was going to be too much.   I will be daisy chaining them on one channel so each one gets 500W.  Hopefully given their advertised power capacity they should be fine.  

BTW, interesting to note that I have been running our current sub and crossover pretty much exactly the same way Roadranger ran his Peavey setup.  I have the low output on the x-over turned up to about +6db.  I expect I'll have to run it like that even with the second sub but hopefully it should give me a little bigger sound with the additional sub. 

[nchangin]

---

guitarman3001 wrote:

---

nchangin wrote:

They were telling you to get Yamaha subs cause they were the best fit in your budget (low) at the time. 

---

And they still are.  Unfortunately we were never able to find any Club series Mains but we did find one sub.  

I just found it funny that I was recommended the Yamaha Clubs and as soon as I buy one, it becomes cheap crap that must be immediately replaced.    lol....   

---

Hi my name is XXX I have not bought a piece of PA gear in 66 days......

It's all good, think of yourself in a room full of crackheads and you come in with some crack from the ghetto and you ask how to smoke the crack, you get advice from those more experienced but then they keep talking about even better crack. No matter what someone is going to have better crack than you and different solutions to smoking the crack, so do not think of the additional suggestion as a literal interpretation that "your crack sucks and you have to toss it" what they are really doing is suggesting "alternatives" to your current solution as they have been in your shoes. 

PA gear can be an obsession and upgrading is an evil bad terrible addiction (to me I know there are others!). A little is good at first then you need more and more and......

[dboomer]

---

guitarman3001 wrote:

 I have the low output on the x-over turned up to about +6db. 

---

Understand that when you do it that way you are turning up the low end of every mic in the system by 6 dB ... your vocal mics, your HH mic, etc.

A better way might be to turn up the bass on those instruments that really need low end by that 6 dB instead.  That way only they come up and you won't be fighting so much gak in the system.

[RoadRanger]

---

dboomer wrote:

---

guitarman3001 wrote:

 I have the low output on the x-over turned up to about +6db. 

Understand that when you do it that way you are turning up the low end of every mic in the system by 6 dB ... your vocal mics, your HH mic, etc.

---

That's partially to compensate for the decreased sensitivity of crappy subs over the tops they are used with. And if your mixer doesn't have decent HPF's (did PreSonus ever upgrade the 6db/oct SL?) all bets are off.

[guitarman3001]

---

dboomer wrote:

---

guitarman3001 wrote:

 I have the low output on the x-over turned up to about +6db. 

---

Understand that when you do it that way you are turning up the low end of every mic in the system by 6 dB ... your vocal mics, your HH mic, etc.

A better way might be to turn up the bass on those instruments that really need low end by that 6 dB instead.  That way only they come up and you won't be fighting so much gak in the system.

---

Hadn't thought about that.  Thanks for that info.  I'll make a point to try it that way at next weekend's gigs. 

btw, our mixer does have a 75hz HPF which I have engaged on all the vocal mics.  That should help a little.  

[twostone]

---

guitarman3001 wrote:

 

hrmm...actually, we just bought one of those entry level subs.   We're a small and poor band and can't really afford much more.   Hey, we've come a long way since the days when the only thing we ran through the PA, which consisted of a pair of Yamaha A12s with an old Nady 800 watt amp pushing about 200W/ch into each speaker, was the vocals.  We didn't even mic the kick drum. 

Now we have a full PA with two subs, a couple of decent amps, we're running everything through the board, and despite this stuff being considered "entry level" to many people, it's a big step up for us and it's about as close to a "real" PA as we've ever had.   Maybe in another year or so we can start looking into replacing the gear we just bought but for now, it works great for the size rooms and type of gigs we play.   Main thing I'm wondering about is how to power the subs and it looks like I got my answer.  Daisy chain them off of one channel so each one gets 500W.  

I'm also curious about the limiter someone else mentioned and how adding one would increase the perceived volume of the kick drum.  The board we have has a single knob compressor on each channel.  Would it help to use that on the kick drum?  Right now I'm just using it on vocals.  

---

Sorry to bust your bubble but they are what they are what they are, which is  entry level subs and gotta power them within their limits and everybody telling you the GX7 is to much amp esp if you get low end feedback and don't kill the FB in time will toast those drivers.  Hell when I joined this place back in 05.  I was told straight up that my PA was  big pile of sh*t and I apologize to those for not passing out gas mask to those folks that  replied back to my post for my big ole big sh*t that was stinking up the forum with toxic sh*t fumes, LOL 

But at the time is was bitter pill to swallow but I finally swallowed that pill and sold my pile of sh*it for pennies on the dollar and started over and bought a little at time as budget allowed. FWIW I'm not saying your subs are pile of sh*t since eBay full of megawatt subs for $0.99 that will blow the roof off a bar according to their marketing sales pitch as. LOL

[guitarman3001]

---

twostone wrote:

---

guitarman3001 wrote:

 

hrmm...actually, we just bought one of those entry level subs.   We're a small and poor band and can't really afford much more.   Hey, we've come a long way since the days when the only thing we ran through the PA, which consisted of a pair of Yamaha A12s with an old Nady 800 watt amp pushing about 200W/ch into each speaker, was the vocals.  We didn't even mic the kick drum. 

Now we have a full PA with two subs, a couple of decent amps, we're running everything through the board, and despite this stuff being considered "entry level" to many people, it's a big step up for us and it's about as close to a "real" PA as we've ever had.   Maybe in another year or so we can start looking into replacing the gear we just bought but for now, it works great for the size rooms and type of gigs we play.   Main thing I'm wondering about is how to power the subs and it looks like I got my answer.  Daisy chain them off of one channel so each one gets 500W.  

I'm also curious about the limiter someone else mentioned and how adding one would increase the perceived volume of the kick drum.  The board we have has a single knob compressor on each channel.  Would it help to use that on the kick drum?  Right now I'm just using it on vocals.  

---

Sorry to bust your bubble but they are what they are what they are, which is  entry level subs and gotta power them within their limits and everybody telling you the GX7 is to much amp esp if you get low end feedback and don't kill the FB in time will toast those drivers.  Hell when I joined this place back in 05.  I was told straight up that my PA was  big pile of sh*t and I apologize to those for not passing out gas mask to those folks that  replied back to my post for my big ole big sh*t that was stinking up the forum with toxic sh*t fumes, LOL 

But at the time is was bitter pill to swallow but I finally swallowed that pill and sold my pile of sh*it for pennies on the dollar and started over and bought a little at time as budget allowed. FWIW I'm not saying your subs are pile of sh*t since eBay full of megawatt subs for $0.99 that will blow the roof off a bar according to their marketing sales pitch as. LOL

---

yeah, I'm not worried about the fact that our PA is a shoestring budget PA.  It works for what we need it for and compares fairly well to the PAs competing bands in our circuit are using.   We mainly play small to medium sized dive bars and some occasional outdoor gigs.  Most of the venues don't want us to be too loud in the first place so my goal with the PA we have is to get it sounding as good as I can.  I think right now we have as much volume as we can realistically use without the club getting bitchy about us being too loud. 

I'm really curious about the compressor/limiter someone mentioned and how proper use of one might get the kick drum to sound louder.  Would the single knob compressor on our mixer help with this or would I need an external limiter?  And if I would need an external limiter, how exactly would it help?

[Craigv]

To address the issue of "everyone" recommending Clubs, I'd be willing to bet they were talking about the Club mid-highs, not the subs. The subs are generally regarded as decent speakers but lacking in output a bit, so they aren't always recommended too heartily.

Compression won't buy you additional volume if the speakers are at or near their limit. Compressing any signal will increase its average power and therefore its apparent volume. But the limit is still the max volume a speaker can produce. The more power you put to a speaker, the more volume it will produce, BUT that increase in volume tapers off. This is called power compression. So going from 1 watt to 10 watts might double volume, but going from 10 watts to 100 watts may only increase volume 50%, and from 100 watts to 1,000 watts may only add another 10% volume, assuming the driver doesn't smoke.

[dboomer]

I think you are mis-calculating for power compression.

Power compression happens with all drivers.  It happens almost immediately and generally it is near its full effect within the first minute of operation (where the VC temp could easily rise by 200 degrees). WRT woofers it is generally more of a problem with smaller voice coil drivers than larger voice coil drivers.

Simply what happens is the resistance of the voice coil goes up with heat.  But you would need a rise of over 500 degrees at the voice coil (copper) to double its resistance.  So if you could actually raise the VC by that much (without smoking it) then your 8 ohm speaker would become a 16 ohm speaker (simplified) and it would put out 6 dB less.

But since not many speakers are gonna run in that range typically power compression at full power will  be around 4 dB, about 2.5 dB at half power and less than 1 dB at 1/10th power.  Since you typically run top boxes at about 1/10th continuous power you'll be closer to a 1 dB loss from power compression.  With subs and compressed material you typically run them at less than 1/3rd power so you could figure about a 2 dB loss from power compression.

So in your example going from 100W to 1000W you'd add more like 50% to the volume, not 10%.

As always ... it all depends

[InACanProducti…]

---

guitarman3001 wrote:

---

dboomer wrote:

---

RoadRanger wrote:

Yup, the problem is that a cab's "program power" rating is usually meaningless and usually just 2x its "rms or continuous power" rating - which is too much for long life on subs in particular. 

---

It's not too much "available" power in my experience.  Typically with 2X available power you will never deliver power equal to half of the continuous rating of the speaker.

It does OTOH have greater consequences when you have stupid mistakes.  It also makes over excurion of the driver a greater possibility.  If you rely only on the amp's built-in clip limiter this could be a problem.  If you use proper a properly set external comp/limiter you could have more protection and a better sound.  Internal clip limiters do not perform like comp/limiters.  When the amp goes into "limiting" it takes down the entire signal that is happening so it's simlutaneously taking down the quiet stuff as well.  External procession only limites the portions that cross above the threshold.  (but that's a different discussion)

The OP's problem is simply he does not have enough speaker to cover his expectations ... pure and simple.

---

The bolded part is what I was trying to get at in my previous post.   Based on what everyone has said, it looks like I'll be ok running these subs daisy chained on one channel.  If not, I'll come back and let everyone laugh at me.  

---

I don't believe that's what everyone has said if you go back and read carefully.  It has been said to use a smaller amp, it has been said that 500w each speaker is the absolute MAX you should be using.

Biggest problem between what QSC told you and the ratings on the speakers is that "Program" isn't Apples to Apples.  QSC's "program" rating isn't a standard spec, and it certianly does not corrilate to any other speaker manufacturer's "program" rating.  In relation to speakers, a "program" rating is usually 2x RMS, but the term program has no real standard definition, it's a marketing term.  RMS on the other hand refers to a measurable spec that is derived from one of the variouse standards of measuring it.

The general advice back in the days when I was more active on this forum was to power a speaker with 1.5x - 2x the RMS rating on said speaker, which also depended on your skill level and what speaker protection you had available.  You are taking the "program" value of your speakers, which is probably around 2x the RMS rating and adding a bit on top of that, which is NOT recommended. 

Given the 2 amps you have, to safely power those subs, I would run both speakers daisy chained to one channel of the XLS for 800watts @ 4ohms, or 400watts to each speaker.

Another thing that hasn't been brought up that you should understand is how increasing your power(wattage) translates into volume. You only get 3dB more SPL for every doubling of power.  So, for example, if you power those subs with 200 watts they will only get 3dB louder if you power them with 400 watts.  Adding another 100watts from 400w to 500w will only yeild and increase of 0.75dB over powering them with 400 watts each (3.75dB over 200watts).  But as has been said previously, the heat, and excursion on the drivers can be more damaging to those speakers at 500 watts if there were to be an accident like someone dropping a mic, or kick drum mic feedback. 

If the tires on your car are rated for 35psi, you wouldn't put 70psi in them (2x) and then throw in a few extra PSI for good measure, if you did the first pot hole you hit would cause a catistrophic failure.  That's what we're talking about here.  With proper power matching, and even somewhat reasonable over powering, your gear should survive those "oops" moments, but go above and beyond what's reasonable and your S.O.L.  For speakers, the reasonable over powering is around 1.5x the RMS spec, and NO MORE than 2x that spec in the hands of someone seasoned.  If you're playing and mixing, you're better off sticking to the lower end of that range as you won't be able to quickly kill feedback in the sub, especially if you're standing on stage behind it and don't hear the feedback...the smoke you'll see, and smell though.

You can do what you want, but keep in mind that those of us offering advice don't have a dog in this fight, the reps at QSC, or PV or Yamaha all do.

[agedhorse]

---

dboomer wrote:

I think you are mis-calculating for power compression.

Power compression happens with all drivers.  It happens almost immediately and generally it is near its full effect within the first minute of operation (where the VC temp could easily rise by 200 degrees). WRT woofers it is generally more of a problem with smaller voice coil drivers than larger voice coil drivers.

Simply what happens is the resistance of the voice coil goes up with heat.  But you would need a rise of over 500 degrees at the voice coil (copper) to double its resistance.  So if you could actually raise the VC by that much (without smoking it) then your 8 ohm speaker would become a 16 ohm speaker (simplified) and it would put out 6 dB less.

But since not many speakers are gonna run in that range typically power compression at full power will  be around 4 dB, about 2.5 dB at half power and less than 1 dB at 1/10th power.  Since you typically run top boxes at about 1/10th continuous power you'll be closer to a 1 dB loss from power compression.  With subs and compressed material you typically run them at less than 1/3rd power so you could figure about a 2 dB loss from power compression.

So in your example going from 100W to 1000W you'd add more like 50% to the volume, not 10%.

As always ... it all depends

---

Note that there are 3 components to power compression, thermal, mechanical and electromagnetic. All 3 combine at hogher powers to create more losses than thermal alone. For subs, electro-magnetic and mechanical are significant issues.

[InACanProducti…]

---

guitarman3001 wrote:

---

agedhorse wrote:
For what you were willing or able to spend, it's the best option. It's likely that you didn't understand that the best option was not adequate to your expectations

I agree with don that quality powered speakers (not cheap powered speakers) are your best bet.

---

I think it'll meet my expectations.  We were managing ok with the single Peavey sub but needed something to beef up the low end a little bit and give us a more balanced sound throughout the entire room rather than having the bass be significantly stronger on one side of the room, which is what was happening with the single sub.  The additional sub should suit our needs ok.  My biggest question was just what's the best way to power them and if running them with 725W each was going to be too much.   I will be daisy chaining them on one channel so each one gets 500W.  Hopefully given their advertised power capacity they should be fine.  

BTW, interesting to note that I have been running our current sub and crossover pretty much exactly the same way Roadranger ran his Peavey setup.  I have the low output on the x-over turned up to about +6db.  I expect I'll have to run it like that even with the second sub but hopefully it should give me a little bigger sound with the additional sub. 

---

Ever thought about bringing the mid/high output down 6dB?  Just a thought.

[dboomer]

---

agedhorse wrote:

Note that there are 3 components to power compression, thermal, mechanical and electromagnetic. All 3 combine at hogher powers to create more losses than thermal alone. For subs, electro-magnetic and mechanical are significant issues.

---

Indeed!  Just trying to keep the explaination simple and understandable.  I didn't want to lose anyone with references to reduction in the speaker's electromechanical coupling factor.  I also didn't mention that it changes the tuning of the box which changes the sound quality and negatively affects the speaker's power handling capabilities.  It also causes a shift in the cone over-excursion frequency.

The typical loss in dB that I stated does take into account these components and I just wanted to point out that while power compression is unavoidable it is not the huge problem that some think it is.  It's also fair to point out that some speakers like Peavey's neo-BW series and JBL's vented gap systems are affected far less than comventional non vented drivers with similar sized VCs.

[agedhorse]

On subs, each of the 3 components can cause roughly 1/3 of total power compression. I understand keeping it simple, but on subs I think it's more important. The power compression factor tends to be around 6dB total at ~the RMS rating of today's average sub driver. Go to program and you may lose 2 of the 3 dB you hope to gain.

On heavily high passed drivers (say 100Hz and up) the two factors that I mention are less of a contribution.

[dboomer]

---

agedhorse wrote:

 The power compression factor tends to be around 6dB total at ~the RMS rating of today's average sub driver. Go to program and you may lose 2 of the 3 dB you hope to gain.

---

I guess it depends what you call average.   According to JBL engineers about -7 dB for a 2.5" VC, about -4.5 for a 4" conventional VC and about -2.5 dB for a vented 4" VC.  It's a pretty difficult spec to get your hands on.

I don't know what you mean "go to program".  If you actually deliver the program rating you have probably smoked the speaker.  Few users are actually "delivering" what they think they are in my experience.

[agedhorse]

---

dboomer wrote:

---

agedhorse wrote:

 The power compression factor tends to be around 6dB total at ~the RMS rating of today's average sub driver. Go to program and you may lose 2 of the 3 dB you hope to gain.

---

I guess it depends what you call average.   According to JBL engineers about -7 dB for a 2.5" VC, about -4.5 for a 4" conventional VC and about -2.5 dB for a vented 4" VC.  It's a pretty difficult spec to get your hands on.

I don't know what you mean "go to program".  If you actually deliver the program rating you have probably smoked the speaker.  Few users are actually "delivering" what they think they are in my experience.

---

Assuming program rating is2x the RMS or "continuous" rating.

The Yamaha subs use a conventional round wire 2 layer 3" voice coil. Pretty "average" for the MI field IMO.

The problem with subs is that you have back EMF and generated nagnetic field from the current through the voice coil changing the magnetic field from the PM magnet structure plus the effects of mechanical suspension non-linearity that increase losses as a function of excursion... 2 non-linear equations that yield a net loss that grows with amplitude.

[WynnD]

I had seen a spec sheet on the SW118 Yamaha that suggested it might be a 4 ohm cabinet. An 8 ohm cabinet will have a DC resistance of about 6 ohms.

[tlbonehead]

350-400RMS would be the most I'd use with those speakers, and hopefully with 40-50hz lo-cuts.