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Amp advice

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Category: General
Forum Name: Amp Forum
Forum Description: The 'Stopping Jake Fielder moaning constantly' forum description...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=104684
Printed Date: 05 April 2020 at 2:46pm
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Topic: Amp advice
Posted By: Slipshod
Subject: Amp advice
Date Posted: 08 January 2020 at 3:27pm
Hey, 

I'm a bit of a newbie, so I'm after an amp to power my 4x 800w USB2's 

I was told not to get a MC2 E15 for £450 as this would only be 350w ish per sub (maybe I couldhave ran it in bridge at 3000w though?)

I've also been offered a Matrix xp3000h for £425, this should run my subs at 750w each at 4ohm (2 on each channel) 

Is the Matrix worth the money, i'm not sure of the age of it, but it's recently been serviced.

I'm also after any other alternatives (ideally cheaper)

Would I be better getting 2 1500-2kw amps and splitting the subs up?

I just missed out on a proline 3k for £250 which i'm pretty sad about but something in that price range would be ideal!

Any advice would be great :D 





Replies:
Posted By: RobinMatrix
Date Posted: 09 January 2020 at 1:18am
It all depends on what you mean by "800w"

Is that the AES rating or the programme rating?

If it is the programme rating an amp doing around 1500W a side into 4 Ohms would be about right, a typical "3K" amp.

If that is the AES rating, you basically want double that.  What actual drivers are in the subs?


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Matrix Amplification Limited :: http://pa.matrixamplification.com/" rel="nofollow - http://pa.matrixamplification.com/"


Posted By: jacethebase
Date Posted: 09 January 2020 at 7:58am
I have P3000RL’s going for £300+VAT at the moment.

There my last ones, hence the price. Not the cleanest but work.


-------------
www.wedding-production.co.uk

www.stage2sound.com


Posted By: Slipshod
Date Posted: 09 January 2020 at 4:35pm
Originally posted by RobinMatrix RobinMatrix wrote:

It all depends on what you mean by "800w"

Is that the AES rating or the programme rating?

If it is the programme rating an amp doing around 1500W a side into 4 Ohms would be about right, a typical "3K" amp.

If that is the AES rating, you basically want double that.  What actual drivers are in the subs?


good question! I'm not too sure as I got the subs second hand, but assuming they are the original drivers this is all the info I have on them. 

https://www.stableaudio.co.uk/flux-series-usbv2 - https://www.stableaudio.co.uk/flux-series-usbv2 


Posted By: Mikkel
Date Posted: 09 January 2020 at 5:24pm
I dont know if they are the original drivers but i bought 4 fane 18b800's that had come out of some usb2's. Could be the same seeing as the 'watt' figure is the same. Very good drivers if they are. If you can open them up and post some pics im sure the community could confirm for you.


Posted By: RobinMatrix
Date Posted: 10 January 2020 at 1:58am
Originally posted by Slipshod Slipshod wrote:


good question! I'm not too sure as I got the subs second hand, but assuming they are the original drivers this is all the info I have on them.


So, let's assume they are the original drivers,  and Tom always uses good quality products, so they should be.

The cabs are rated  800 watt AES  so they'll take around 1600W programme and I would recommend you look for an amplifier that will deliver about 3200W into 4 ohm per  channel, 6400W total.

I would not recommend our 3000W amplifer, the XP3000H you mentioned earlier, that would be too small, only about half the needed power.

If it was an amplifer from our range, I would recommend the XT5000MF (maybe just a little too small) or the XT7000MF (just a little too big, don't drive it too hard!) I'd probably go for the 5000 if it was me.

There are of course many other brands and styles, but something around that sort of size shoudl drive them nicely.


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Matrix Amplification Limited :: http://pa.matrixamplification.com/" rel="nofollow - http://pa.matrixamplification.com/"


Posted By: Slipshod
Date Posted: 10 January 2020 at 3:46pm
Originally posted by RobinMatrix RobinMatrix wrote:

So, let's assume they are the original drivers,  and Tom always uses good quality products, so they should be.


Thanks for all the advice! I'll open them up and get a photo of the drivers tonight :)

So my MT's ( https://www.stableaudio.co.uk/flux-series-kmtv2 - https://www.stableaudio.co.uk/flux-series-kmtv2) are AES so I assume this is why running them on my behringer KM1700s are clipping at such low Volumes? 

Got 2 of these amps with the speakers along with an ultradrive, was hoping to use 1 for the mids, 1 for the highs and get a third for the subs but being AES I may need to upgrade all the amps? 


Posted By: Slipshod
Date Posted: 10 January 2020 at 6:39pm
Hey, so you're right, they are Fane and also AES

https://www.fane-international.com/view-product/COLOSSUS-18-800N - https://www.fane-international.com/view-product/COLOSSUS-18-800N

if i'm honest, there's no way I can afford the XT5000MF atm, If I was to get the XP3000h, would I still be able to power them to a half decent level and get another 3kw amp in the future to give them the power I need? 


Posted By: Mikkel
Date Posted: 11 January 2020 at 6:06am
Originally posted by Slipshod Slipshod wrote:

Hey, so you're right, they are Fane and also AES

https://www.fane-international.com/view-product/COLOSSUS-18-800N" rel="nofollow - https://www.fane-international.com/view-product/COLOSSUS-18-800N - https://www.fane-international.com/view-product/COLOSSUS-18-800N" rel="nofollow - https://www.fane-international.com/view-product/COLOSSUS-18-800N

if i'm honest, there's no way I can afford the XT5000MF atm, If I was to get the XP3000h, would I still be able to power them to a half decent level and get another 3kw amp in the future to give them the power I need? 


Yea i had the ferrite version, its the same cone looking at the mms on the spec sheet. Tbh mate you will be fine running them on the xp3000, they are very light cones (so very efficient) and dont require a thrashing to get them singing. You might as well 'underpower' and make some noise, just be careful on the clipping s'all.


Posted By: RobinMatrix
Date Posted: 11 January 2020 at 12:28pm
Originally posted by Slipshod Slipshod wrote:

, If I was to get the XP3000h, would I still be able to power them to a half decent level and get another 3kw amp in the future to give them the power I need? 


Sadly, no.   Running one cab per side on a pair of 3K amps would not deliver any more power overall (well, a small amount, but not noticeable) than running 2 cabs per side off 1 amp.

Basically, a "3K into 4 ohm" amp of any flavour doesnt deliver enough voltage ... you need roughly 70% more voltage than it provides.    Using 2 amps will not help.

You could bridge one, but that would then be more voltage than you need, and also it would only be able to drive one cab.


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Matrix Amplification Limited :: http://pa.matrixamplification.com/" rel="nofollow - http://pa.matrixamplification.com/"


Posted By: RobinMatrix
Date Posted: 11 January 2020 at 12:33pm
Originally posted by Mikkel Mikkel wrote:


Yea i had the ferrite version, its the same cone looking at the mms on the spec sheet. Tbh mate you will be fine running them on the xp3000, they are very light cones (so very efficient) and dont require a thrashing to get them singing. You might as well 'underpower' and make some noise, just be careful on the clipping s'all.


To be fair, an XP3000H will make a decent bit of bass through them, the slight worry is that if he is already clipping his 1700 it's not going to make that much more noise ... clipping is the danger, more drivers are lost to clipped low power amps than being overdriven by big amps.

In the end, it all depends on just how much bass you need I guess ... people used to be quite happy with an XP3000 on bass duty ...  a 5K would drive them fully, but if you can live with less bass, then the 3000H won't be a bad result at all.



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Matrix Amplification Limited :: http://pa.matrixamplification.com/" rel="nofollow - http://pa.matrixamplification.com/"


Posted By: Slipshod
Date Posted: 11 January 2020 at 1:34pm
Thanks for all the help guys :) 

So the guy selling the xp3k i coming to run it on my subs later, this morning I got the rig out and discovered a few things. 

I tried to bi amp the mids/highs the mids, even when only 1 was connected with the power turned down to 0 was clipping hard and making cracking noise, I tried a few configs of this, swapping cables, swapping amps, running 1m, 1h off 1 amp etc...basically the mids on both speakers clip instantly...I thought this was the KM1700s not being powerful enough so I plugged 1 sub into each channel and I can get a shit ton of bass out of them even with the Behringer amp...

So what's going on with my mids, Are the drivers blown?


Posted By: Slipshod
Date Posted: 11 January 2020 at 1:38pm
I got a noise complaint from across the road before the 2 subs off the KM1700 came even close to clipping. I can even run mids clear, but the minute both high and mids are connected it crackles.

Hoping it's just something silly i'm doing with the crossover, it's currently running in Stereo if that's any help.


Posted By: Timebomb
Date Posted: 11 January 2020 at 1:57pm
The difference between 1500W into 4 ohms (77.5Vrms) and 2500W into 4 ohms (100Vrms) is 2.22dB, its not a huge amount, if 2.22dB is making you push your amps into clip then your not bringing enough rig for the gig.  You dont have to rag every last dB out of your speakers, generally it sounds better if you dont.

Imo 1-1.5x the AES driver rating is plenty, 2x is too much but you can always use a bigger amp and limit it, im not into this 2xAES thing as a "standard", can be ok for mid high but not bass and sub.

  The Colossus 18B-800 is rated at 800W AES, sqrt(800x7ohms) = 75Vrms.  That rating is in free air, so once you put it in a cabinet and restrict the airflow around the motor it will reduce the thermal handling.

Id say the XP3000H will do the job fine.  


-------------
James Secker          facebook.com/soundgearuk
James@soundgear.co.uk               www.soundgear.co.uk


Posted By: RobinMatrix
Date Posted: 11 January 2020 at 2:01pm
You'll have to explain more how you are linking up the mids ... 

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Matrix Amplification Limited :: http://pa.matrixamplification.com/" rel="nofollow - http://pa.matrixamplification.com/"


Posted By: 4D
Date Posted: 11 January 2020 at 2:09pm
Did you say Ultradrive.. ?   Nothing sounds as nasty as a dcx hitting its internal limiters. 



Try the reducing the gain on the inputs -14 is good  and raising the limiter threshold so peak output level is nowhere near activating the channel limiters  ,

If that makes sense.. 


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DMZ. "The bass was intense. Girls were literally running up to stand next to the subs"


Posted By: RobinMatrix
Date Posted: 11 January 2020 at 2:43pm
I suspect there is some "one amp driving into another amp" or something similar going on ...eg. his mid-hi boxes are linked internally and conencting both mid and hi sockets to an amp ends up with them fighting. Something like that going on would be my guess.



-------------
Matrix Amplification Limited :: http://pa.matrixamplification.com/" rel="nofollow - http://pa.matrixamplification.com/"


Posted By: njw
Date Posted: 11 January 2020 at 10:25pm
Originally posted by Timebomb Timebomb wrote:

The difference between 1500W into 4 ohms (77.5Vrms) and 2500W into 4 ohms (100Vrms) is 2.22dB, its not a huge amount, if 2.22dB is making you push your amps into clip then your not bringing enough rig for the gig.  You dont have to rag every last dB out of your speakers, generally it sounds better if you dont.

Imo 1-1.5x the AES driver rating is plenty, 2x is too much but you can always use a bigger amp and limit it, im not into this 2xAES thing as a "standard", can be ok for mid high but not bass and sub.

  The Colossus 18B-800 is rated at 800W AES, sqrt(800x7ohms) = 75Vrms.  That rating is in free air, so once you put it in a cabinet and restrict the airflow around the motor it will reduce the thermal handling.

Id say the XP3000H will do the job fine.  
  

 Pretty much my thoughts exactly, modern music contains lots of very low frequencies and is often highly compressed, then feeding the signal through a red lining dj mixer is only going to make things worse. 1.5x AES is ample on bass imo. 
 Up until recently I was running 6x 600w 18" reflex bins on bass, one pair on a Matrix STR2000 (600w per driver) and the other two pairs on an STR3000 (750w per driver), it was only in the larger venues with a few hundred people in front of the system that I would see the occasional clip light, I wouldn't have gained any more output from larger amps, I would have definitely gained headroom but then you run the risk of things being pushed a bit harder as you have power in reserve and running the drivers into higher thermal compression.  

 Also, four of the above mentioned 18's are now in a local venue of about 200 capacity being 'underpowered' by a 1.5kw amp, I've set the limiters to just about keep the amp out of clip and they do a pretty good job of shaking the place just fine. Smile
  


Posted By: Slipshod
Date Posted: 15 January 2020 at 3:26pm
Originally posted by RobinMatrix RobinMatrix wrote:

I suspect there is some "one amp driving into another amp" or something similar going on ...eg. his mid-hi boxes are linked internally and conencting both mid and hi sockets to an amp ends up with them fighting. Something like that going on would be my guess.



This is a possibility for sure, although they are bi amped MT's...I've managed to get them working but I couldn't tell you what the cause was. 

I have a whole bunch of cables, could it be that I'm using the wrong ones for the tops? As in, do I need 4 pole for bi amping and 2 pole for subs? 

I'm going to buy the Matrix 3k as a starting point, It's mainly for free parties so i'm not after event quality sound (although i'm sure any Matrix is great).


Posted By: DMorison
Date Posted: 16 January 2020 at 1:40pm
Originally posted by Slipshod Slipshod wrote:

Originally posted by RobinMatrix RobinMatrix wrote:

I suspect there is some "one amp driving into another amp" or something similar going on ...eg. his mid-hi boxes are linked internally and conencting both mid and hi sockets to an amp ends up with them fighting. Something like that going on would be my guess.



I have a whole bunch of cables, could it be that I'm using the wrong ones for the tops? As in, do I need 4 pole for bi amping and 2 pole for subs? 

Absolutely - if you had somehow managed to connect 2 amp channels to a 2 pole cable, you could have very easily been shorting the outputs of those 2 amps together as Robin guessed.


Posted By: Slipshod
Date Posted: 18 January 2020 at 5:49pm
Had the guy selling me the Matrix look over my setup, both speakons are 4 pole on the back of my midtops which is why it was shorting 2 amps together, he said I will need some sort of junction box for 2, 4 pole cables to go into that then connect 4 wires onto the terminals? 

If anyone can point me in the right direction of leaning more about this sort of thing would be great!

Also discovered a rattle in 1 of my subs...still need to take the driver out to diagnose as I can't see the cone, but guessing i'll be sending it off to Fane.



Posted By: njw
Date Posted: 18 January 2020 at 9:16pm
Originally posted by Slipshod Slipshod wrote:

Had the guy selling me the Matrix look over my setup, both speakons are 4 pole on the back of my midtops which is why it was shorting 2 amps together, he said I will need some sort of junction box for 2, 4 pole cables to go into that then connect 4 wires onto the terminals? 

If anyone can point me in the right direction of leaning more about this sort of thing would be great!


   

 Can you post some pictures up? 
 


Posted By: Danielr
Date Posted: 21 January 2020 at 11:35pm
As an example where you might find a wiring diagram instead of the picture, I had that wiring in a pair of peavey impulse 200 speakers. I naively assumed that the speaker would only be attached to 1+ and 1- but actually it is attached to 1+ and 2+ in parallel. Same with 1/2-...

To get around this...
What I have is subs with a 4pole speakon. Wired on channel 1. And just passing through the ins to an out speakon.  Then I have a link wire where only ch2 is connected inside the speaking plugs, That way I can use a single 4core speaker cable from the amp rack to speakers, bass on ch1 mid top on ch2.

The wiring arrangement of the mid top cabinet is frustrating when you just assume it'll be wired to a single channel of the 4pole speakon. But actually not all that bad. (In my case the amp (also matrix) popped the mains fuse but lived to fight another day.) 
Once you realise the connections though it actually makes for a quite flexible setup... 

I can run a small gig using those speakers full range. with 1 amp on ch1, or a larger gig with bass on ch1 and that custom link cable for ch2. 

Just make sure you know the wiring on the output of your amp/patch panel/ speaker in future :)



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