Dec 23, 2009 03:24 pm bumppp help por favorr!
NEED SERIOUS HELP WITH AMP/SPEAKERS SETUP!
Posted on Dec 23, 2009 11:01 am
PatrickReza
Member Since: Dec 23, 2009
Hey guys so I' brand new to the forums, but I'll start off by saying I'm a live dj and need help with my audio setup...ever since now, i've been powering two JBL G-732s ( www.jblproservice.com/pdf/G-Series/G-732.pdf ) with an NAD 7600 ( nadelectronics.com/img/datasheets/NAD_7600.pdf ), now that my 7600 is dead I need to find a new amp, I really need help because I don't know a thing about ohms or wattage, so I was wondering what the minimum requirement for my speakers? whats best for them? etc because I need to get a new amp ASAP.
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Dec 23, 2009 03:40 pm Here is an amp that will work for your situation. QSC Audio GX-3
www.qscaudio.com/products/amps/gx/gx.htm
Here a link to Zz sound for it.
www.zzounds.com/item--QSCGX3
Dec 23, 2009 04:51 pm Hummmm, for some reason, the link to zZ sounds isn't working. Well, just follow the link to the site, and search for the QSC GX-3.
Dec 23, 2009 04:52 pm weird, my automated rewriting suddenly broke the links. CRAP.
Oh well, the snow started, I got nothin but time. :-)
Dec 23, 2009 04:54 pm Ok you HAVE to be kidding me...zZounds messed with something...damnit.
Dec 23, 2009 04:58 pm Come on Electric Company! Keep Dan's power on!
So our favorite site does not crash!
Dec 24, 2009 01:29 am and that amp will not underpower them? because its only 300watts... and dont the speakers put out 400W each? sorry i dont know much ahah and also will this be as loud as the nad?
Dec 24, 2009 11:33 am Speakers don't put out anything themselves, speakers onlyput out what the amp gives them. That amp would work just fine.
Dec 24, 2009 11:53 am Easiest rule of thumb: Always push speakers with an amp thats less than or equal to the RMS wattage of the speakers. Otherwise, you risk pushing too much wattage to the speakers and potentially blowing them out! In your case, a 300 watt or 350 watt amp powering 400 watt speakers is perfect.
Dec 24, 2009 12:23 pm ok sounds good, i just need it to be loud so 400w times 2 speakers is fine? because i would think you
d need at least 800 watts to fully power em...
sorry guys im a complete newbie not trying to troll
Dec 24, 2009 12:25 pm and also willl it be as loud as the nad? just wondering
Dec 24, 2009 01:10 pm How loud your speakers get, is up to the loud speakers themselves.
That is a function of SPL (Sound Pressure Level) And it's all about the way the speakers push the air.
Wattage is all about the mechanical portion of the speaker. How much energy it takes to move the speaker.
If you are putting both speakers on one side of the amp in parallel, then you need to up the wattage.
If you are running in stereo, then you need to match the rms rating of the speakers.
In your case. the cabinets have two ratings that the show. Continues Pink, and continues program. Which are a little confusing for someone shopping for an amp.
Continues Pink, is all full range is all frequencies at full. So, no dynamic peaks. Just a constant push.
Continues program, is more or less any music with the max peak the speaker can take.
This translates to "Pink" being the rms rating. And Program being close to the peak.
We want to fall in between the pink and program ratings. The GX-3 does that for you. And is not to little, or to large for yor ratings.
Remember, an amp does not just to go the listed rating, and then stop. It will exceed the rating when pushed. these ratings are for ideal normal conditions. It is not unusual for an 350 watt amp, to peak at 400, or higher before it clips.
I have to disagree with Hippie about the rule of thumb. I like to have an amp that is larger then the rms listing. Reason being, that it is harder to overpower a speaker, then it is to squarewave a speaker.
When you are running a small listed amp, The speaker is able to absorb the wattage. But the amp will struggle to produce the max wattage. Most of the time, this leads to over pushing the amp into clip.
when the amp is in a constant clip, then a squarewave is produced. A squarewave is the deadliest form of a wave. Destroying all in it's path. Heat, being the worst enemy of all electronics.
Bottom line, if you are running the amp in stereo, then the amp I suggested is fine. If you are running both speakers off of one side of the amp, then you may wish to look at the GX-5.
Dec 24, 2009 02:08 pm is this amp okay? i just want a cheap powerful amp
www.guitarcenter.com/Vest...022-i1397753.gc
Dec 24, 2009 02:10 pm or would that underpower them? so youre saying this---www.guitarcenter.com/QSC-...845-i1388204.gc would be good
Dec 24, 2009 02:27 pm Not to beat up on Vestax........... But, they are not known for top shelf amp products.
And customer service with them........ Forget it!
The QSC is a great choice.
Dec 30, 2009 10:21 pm @ hippie
sorry thats not really true - and fatal for speaker / amp set ups.
look at it like this: the speaker gets an electric signal from the amp to make a sound. the louder the more power is consumed and the bigger the speaker the more power he needs to perform.
every push has its kickback: every time the speaker swings back into neutral position he produces a signal (by induction) which is going back to the amp. the amp has to equal this voltage with the outgoing voltage and pushes more power in it.
the point of distortion is usually when the incoming power is - and then already audible - disturbing the outgoing signal, which is close to clipping and burning the coil or short cutting the power amp.
so far my engineering colleagues explained it to me. better you always connect "bigger" amps to "smaller" speaker to avoid the risk of frying the system. unless you have an amp that compensates this, there are amps with this features on the market.
so long!
jp
Dec 30, 2009 11:57 pm Hey Dean. I think that you have most of the concept down, but not all of it.
Yes it is true that an coil will have an inductance kick to it. It's the nature of the beast. As a magnetic field builds in a coil, and makes the elector magnet. The speaker has magnet in it's construction, and as the fields match in strength, the speaker moves either in or out.
Now, when the field flips, the built up field, must collapse through the coil of wire. And if you know how electricity is made, this creates an electrical charge.
With any electrical charge, it moves from where it is highest, to it's lowest power. So, it moves to where electricity is at it's weakest. Or anything close to ground.
An amp has a floating ground on it's output. As one side is building in charge, the other is weakening. Causing the current to flow towards the weaker side. This way, the in rush current doesn't have to fight very hard to over run the inductance kick.
In the amp it's self, there are also ways of controlling inductance kick. By putting a diode in parallel with the output transformer. But, this was with the old liner amps. And was more about the turning on and off the amp. So that your speakers didn't get hit with a large pulse with the in rush, or out going current.
With the new switching amps, this is rather a non issue.
Speaker voice coil design has more to do with controlling the inductance kick. By winding the coil with the wire on edge, instead of flat. Helps reduce the amount of kick the coil produces. (Less exposed surface.) And the amount of voltage will not equal the in rush voltage. Pushing the current to the low side of the amp.
One of the main causes of distortion from overpowering a speaker is the voice coil is no longer running true. That is to say that the voice coil is now resonating due to the fact that it is trying to shift in the air gap. Due to extreme large magnetic fields trying to pull the voice coil out from the gap.
Another cause of distortion from overpowering is heat. Heat causing the voice coil to swell, and rub against the air gap. There are also about 100 other reasons that heat causes distortion as well with overpowering the speaker. Such as THD percentages. (Thermal Heat Distortion) But, I won't go over all of them right now.
Bottom line is that you still want an amp to be larger then the listed rms value. And that is what you have listed in your post as well. As long as you stick to this theory Patrick, your going to be fine. Just don't try to do something crazy. Such as trying to push over a 1000 watts through a 200 watt speaker. Unless you have 5 16 ohm 200 watt speakers that is. :)
Jan 01, 2010 12:53 pm hello rob,
yes that explains it very well. i guess with professionell equipment this issue should be solved by switching amps.
hope that patrick already found what he was looking for, w/out any trouble at all.
sorry for the confusion
dean
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