Peak LED

[mark_richards 0]

Hi,

I have a Pro Sound 400w (max power), Stero Amp and 300w (Max Power) speakers. These were bought in Maplins and are sold as a bundle. (www.maplin.co.uk for more info).

 

On the last gig I done I noticed that LED's on the amp below the worf 'PEAK' were flashing. http://www.dj-forum.co.uk/html//emoticons/oops.gif I have never noticed this before. The levels on the amp were only about half way (maybe a bit over) but the levels on the mixer were pretty high.

 

Is it a bad thing when these lights start flashing? Should I be arranging my levels in a different way? http://www.dj-forum.co.uk/html//emoticons/533.gif

 

Thanks for you help

 

Mark

 

http://www.dj-forum.co.uk/html//emoticons/wallbash.gif

[cookiecat 0]

I could be way of the mark here, but keep the master on the mixer low so your leds on the mixer only ever reach their peak occasionally and not in the red the whole time.This way ensures that there is not to strong being sent to the amp.

 

 

Or I could be talking http://www.dj-forum.co.uk/html//emoticons/pooh.gif

[ChrisPointon 0]

Occasional flickers of the 'peak' lights are okay, but if they are flickering all night or you reach levels where they are lit continuously then you may like to consider another, larger capacity amplifer.

 

The peak lights indicate the point where your amplifier has reached it's maximum output levels and is being overdriven, this is called clipping, and it's also the point where the nice steady, smooth waveform which your amplifier has been producing to your speakers, turns into something resembling King Kongs heartbeat http://www.dj-forum.co.uk/html//emoticons/biggrin.gif . In other words, when it starts to clip, it also begins introducing large amounts of distortion into the audio.

 

Severely clipping amplifiers can burn out voice coils in speakers and HF horns, resulting in damage if it continues for long periods, so often it is false economy not to upgrade, if it is a regular occurance, since replacing speakers isn't cheap.

 

It's a good idea to have a larger wattage amplifier, and run it at around 50% of it's output power, rather than a low power amp and be driving it at 90%+ all night.

 

I often use a car analogy when describing amplifiers, in that it is better to drive at 70mph in a Jaguar, than in a Citroen 2CV. Both will reach the speed, but one will hold 70mph with far less strain and more comfort than the other http://www.dj-forum.co.uk/html//emoticons/smile.gif . The same applies to amplifiers.

 

 

The Prosound is a little bit underpowered for mobile use since it only actually produces 100W RMS per channel into one pair of speakers (8 ohms) so whilst it is a good amplifier perhaps as a back up, I really wouldn't recommend using it at every gig, since you would be driving it hard to obtain any volume.

 

When looking at buying amplifiers and loudspeakers, the only true comparison figure of wattage is the RMS figures since these represent the true continuous design rating of the amplifer, any peak or maximum figures should largely be ignored.

 

For most mobile work with 50 - 120 guests, you need to be looking at a system which delivers at least 600W (300W RMS Per Channel) for small gigs and ideally 1000W (500W RMS per channel) or more if you can afford. Unfortunately, this would also mean upgrading your current speakers too http://www.dj-forum.co.uk/html//emoticons/sad.gif .

 

So my advice, is to perhaps look at upgrading your sound system (Amplifier and Speakers) to something a little bit more substantial, and this means avoiding Maplin http://www.dj-forum.co.uk/html//emoticons/smile.gif .

 

A Good Amplifier to look out for, is the Behringer EP1500, but if budget is tight, then I would look at the C-Mark amplifier range, there is a review of them Here

 

Speakers also depend on your budget too, but recommended speakers amongst DJ's tend to be Behringer, Hk Lucas, Mackie & FBT MAXX. However if these are out of your budget then look at the Class D series (Review Here) or the Soundlab ABS Range (Review Here)

[otronics 0]

Cookiecat has it - you need to keep all levels in the green (or in some cases yellow) but make sure they never go into the red.

 

Best way to get levels correct is to prefade (ie/ don't send audio to the mix) every track before you play it. You can adjust the gain to suit.

 

If the levels are correct on the mixer and it is still peaking on the amp, then something is up, and could be to do with the input voltage on the amp (if it is adjustable).

 

Although you have said this has not happened before so that may not be a problem.

[Gary 0]

In the interim, until getting a larger amp, you will often find that turning the bass controls on the mixer can have a surprising result on reducing the appearance of the red peak LEDs.

[superstardeejay 0]

Yep I agree with all that too, I've actually got a ProSound 400W in for repair at the moment, and believe me the description on the front panel of it being 400W is, lets say somewhat ambitious.

 

Best regarded as a background music amp.

 

 

[DJ Marky Marc 0]

Theres a very good reason why they make the peak / clip LEDs red in colour!

 

ok a little off topic but how can shops like Maplins get away with missleading people into thinking amps and speakers like the ones talked about here are bigger than they realy are ??

 

is it not about time there trading standards made them quote Real RMS numbers or would that upset the chineese computer speaker people who make 5000w surround sound kits for £19.99

 

 

[ChrisPointon 0]

QUOTE

ok a little off topic but how can shops like Maplins get away with missleading people into thinking amps and speakers like the ones talked about here are bigger than they realy are ??

 

They don't really mislead as such, after all the RMS figures are clearly displayed on Maplins website. It's usually that some manufacturers and retailers use those figures as the first number which is quoted on the auction / website / catalogue and rely on the lack of technical experience of the buyer. A lot of budget equipment is advertised in the same manner, namely Skytec, Soundlab and Gemini.

 

Some DJ's don't know the difference and comparison between RMS Continuous and Peak / Maximum figures and so buy the gear on the first set of figures that they are shown. Maybe if enough DJ's spread the word, and give the advice it will eventually put an end to this practice.

 

It's much the same as webhosts who advertise unlimited webspace. Have you ever seen an unlimited hard-drive?, if so where can I buy! http://www.dj-forum.co.uk/html//emoticons/smile.gif . The practice of over marketing a product or service is rife everywhere but not illegal.

[superstardeejay 0]

Plus we all know that the better quality amps will sound better than a cheaper amp although they are the same size on paper. Some cheap amps sound 'shrill' and I suspect (never checked) that they maybe tailor the frequency response to make them appear louder in, say the mid-top register. ....(??)

 

 

[jackwabbit 0]

We had exactly the same problem with a ProSound 1000 Amp; it would peak at half volume while at zero DB on the mixer. In fact we had a Stageline 400 which had a lot more output than the ProSound 1000.

If your budget is tight go for a Behringer EP1500 or 2500, or if you can find anyone selling them C-Mark Amps.

 

[superstardeejay 0]

QUOTE

; it would peak at half volume while at zero DB on the mixer.

 

That doesnt necessarily belie poor output, merely that the input stage has not been calibrated for 0dB at full pot travel....but I know what you're saying.

 

The peak LEDs on some amps are triggered by monitoring the instantaneous voltage level on the output, lighting when a threshold has been crossed. Others use a more complicated circuit whereby the DC bus volts is compared with the output volts, and when the difference is below a set level, that triggers the clip LED. (the latter is a more truthful indication.)

 

Maplins catalogue says in the spec (or at least used to) that the amps have 'clip protection' but if they do, it doesn't work.

 

 

 

 

[Andy Westcott 0]

As regards balencing the mixer levels to the amp, perhaps you could try this:

 

Disconnect the speakers, and ideally if you have the know-how, replace the speakers with a dummy load of about 8 ohms or thereabouts.

 

Then simply set the mixer master control and the amp gain control so that the mixer is just going into the red as the amp's clip light flashes. This way, no single item in the chain is going to clip first, and you can then strive to keep the mixer out of the red, safe in the knowledge that the amp won't be severely clipping either. Also has the added benefit of reducing slightly the quiet background hiss you might have during silence.

 

Best solution though is to buy a better and bigger amp - look at QSC products.

[MatDJ 0]

Iv been wondering about peaking as I tend to have a problem with it from time to time...

 

Could it be as a result of any of the following reasons?:

 

1) need of a better quality mixer. I use a new gemini mpx-3 cd deck and an oldish synergy mixer, if i get a newer mixer will it help?

 

2) my speaker config is kind of wierd too, i have 2x 500w rms skytec amps and attached to one are 2x 250w rms full range prosound speakers (bad i know), if i got a bigger set of speakers would the clipping reduce or will more volume be achieved before more clipping?

 

many thanks

 

Matt. http://www.dj-forum.co.uk/html//emoticons/smile.gif

[DJ Marky Marc 0]

changing the speakers will not reduce clipping.

 

the amp can clip with any size speaers, what you need is a bigger amp so the amp does not reach maximum output before your spakers do....

 

 

[Andy Westcott 0]

That's it really. An amp clipping is simply a sign that you have pushed it to its maximum output. Either turn down the volume a bit, or if you must run at those levels, buy a bigger amp which will provide the same sound level (or higher) without clipping.

[nrgize 0]

QUOTE (MatDJ @ Feb 12 2006, 07:33 PM)

my speaker config is kind of wierd too, i have 2x 500w rms skytec amps and attached to one are 2x 250w rms full range prosound speakers

The speakers are probably 8ohms, and the amp rated at 4ohms. Which means that the amp power would be less to the speakers. The Pro Sound range of speakers tend to be rated per 8ohms.

 

 

 

 

Nathan

[MatDJ 0]

so that means if I got some 4 ohm speakers i would get more volume? http://www.dj-forum.co.uk/html//emoticons/huh.gif

[RobbieD 0]

Red lights = bad!

 

Avoid clipping at all cost. It damages your speakers, and makes your system sound like http://www.dj-forum.co.uk/html//emoticons/censored2.gif !

 

QUOTE (superstardeejay @ Feb 12 2006, 03:28 AM)

QUOTE ; it would peak at half volume while at zero DB on the mixer.   That doesnt necessarily belie poor output, merely that the input stage has not been calibrated for 0dB at full pot travel....but I know what you're saying. Or it could be designed to work with the lower level phono plug output from mixers that don't have XLR outputs, as these kind of amps are probably sold in high numbers to bedroom DJ's.   QUOTE (MatDJ @ Feb 13 2006, 01:56 AM) so that means if I got some 4 ohm speakers i would get more volume?  http://www.dj-forum.co.uk/html//emoticons/huh.gif With a theorectically perfect amp you would get 3dB more output with 4ohm speakers (assuming all other specs, such as speaker efficiency, are the same).   However in the real world theorectically perfect amplifiers don't exist, and you would get more like 1-2dB more volume, which is only just noticeable, and not worth the cost of buying new speakers.

[MatDJ 0]

thanks, bigger amps then, or not so loud.... http://www.dj-forum.co.uk/html//emoticons/huh.gif

[superstardeejay 0]

QUOTE

Or it could be designed to work with the lower level phono plug output from mixers that don't have XLR outputs, as these kind of amps are probably sold in high numbers to bedroom DJ's.

 

Well the ProSound amp I have here (400W) only has the unbalanced 1/4in jacks for inputs; using balanced XLR outputs from a professional mixer will theoretically give much less sensitivity because you can only use half the signal, using phono outs should in theory give the proper levels as its unbal out to unbal in. And as I mentioned, there's no law to say that that fully clockwise gains on a (cheap) amp will give the correct levels anyhow. Remember the DNA amps...later ones had internal gain switches to change the range of the front panel pots!

 

However, many DJ mixers have woefully inaccurate VU meters in relation to output signal. Some of them seem to be just snazzy lights to impress the amateur even if they're marked in dB and/or green-yel-red colours!!! We're not always talking quality here, folks.. http://www.dj-forum.co.uk/html//emoticons/yucky.gif