Ohm's Law, Speaker Wiring Configurations and more...

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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby FDJA » Sun Feb 13, 2005 10:47 am

MusicDoctorDJ wrote:I mostly run two amps with two speakers . . .
I bi-amp, of course!


Hello Music Doctor! I hate to be the bearer of bad news, but if you have 2 amps and 2 speakers, you are not bi-amping...

Bi amping is when you use 2 amps per speaker. That would be 4 amplifiers for one pair of speakers.

A mono amp setup, means you have one amp for the left and another amp for the right speaker.

From the looks of the picture, you have 2 completely different amps. Are you sure you're not running 4 speakers, (2 subs + 2 full ranges), using 1 amp per speaker system? If that's the case it's a standard setup...
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Postby DJ Daddy » Sun Feb 13, 2005 11:16 am

Todd,

First of all, welcome to DJ Gold.

Bi-amping is not, repeat, not using 2 amps per speaker (never heard of that setup unless you are using 70v amps in a stadium type scenerio). The exception to that is that the speaker enclosure can be bi-amped (two inputs, not uncommon). But that is then basically two individual speaker systems in one enclosure. Maybe that is what you wanted to indicate.

I believe John may have mis-typed but bi-amping is using a separate amp for the different frequency spectrums of your music, i.e. one amp/two speakers for the highs, one amp/two speakers for the lows. There can be a case made for tri-amping as well.

Bi-amping can also be just using two one-amp/two-speakers setups to deliver more SPL to the venue. The signal is split pre-amp.


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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby MusicDoctorDJ » Sun Feb 13, 2005 12:09 pm

Nope . . . I didn't mis-type!

I bi-amp some of my speakers . . .

In otherwords, one amp for the highs(horns) . . . the other amp for the lows (woofers)!

Note the crossover above the amps in the photo:

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Here is a front view . . .

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Postby CJ Greiner » Sun Feb 13, 2005 12:50 pm

Quite true -- bi-amping/tri-amping is simply splitting the frequency range between different speakers with an amp providing separate power for each range.

MusicDoctorDJ -- wow! It's quite common for DJ's to bi-amp between subs and tops.... and even for concert venues to tri-amp their tops/mids/bottoms. But to bi-amp a single box? That's unusual!
(Thanx for the pix :) )
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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby FDJA » Sun Feb 13, 2005 1:01 pm

MusicDoctorDJ wrote:Nope . . . I didn't mis-type! I bi-amp some of my speakers . . . In otherwords, one amp for the highs(horns) . . . the other amp for the lows (woofers)!


Okay... That is not true Bi Amping. What you're doing is splitting highs and lows using 2 amps in stereo. One of your amps pictured, is powering the woofers and the other is powering the highs.

True Bi-Amping means you have one amp per filtered section of a full range loudspeaker system. Bi -Amp=2 amps per speaker.

The term "Bi-Amping" is often misused to refer to a standard satelite setup, where one amp drives a sub cabinet and the other drives the full ranges, or the configuration you have.
Last edited by FDJA on Sun Feb 13, 2005 1:27 pm, edited 2 times in total.
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Postby FDJA » Sun Feb 13, 2005 1:06 pm

DJ Daddy wrote:Todd, First of all, welcome to DJ Gold. Bi-amping is not, repeat, not using 2 amps per speaker ...


Thanks DJ Daddy, glad to be here!

Technically yes, Bi Amping is the use of seperate amplifiers to drive the seperate filtered sections of a full range speaker system.

A loudspeaker capable of bi-amping will have 2 sets of jacks, which can be used independently with 2 amps per speaker enclosure, or combined with one power source.
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Postby DJ Daddy » Sun Feb 13, 2005 1:09 pm

John,

That was the exception that I was talking about. I noticed the AC22 but didn't think you would be cutting the mid-range to the 15"ers. Only later did I go look at mine and noticed the cutoff up to about 3K...

Did you rewire the cabs or were they stock that way?

CJ,
It's not that unusual to bi-amp one box; not common but not unusual either. Works best if you have a box (components) that can handle a lot of wattage to get the SPL out there.

Bi-amping (with active crossover) is probably one of the easiest ways to improve sound due to the individual components (i.e. speakers) not having to produce the entire frequency range. It's not without it's pitfalls but a little thought and you really can't mess it up. And, crossovers, even your good AC22 or AC22B from Rane, aren't that expensive.

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Postby FDJA » Sun Feb 13, 2005 1:10 pm

CJ Greiner wrote:Quite true -- bi-amping/tri-amping is simply splitting the frequency range between different speakers with an amp providing separate power for each range...


Correct CJ. This is a really old concept which started back in the day when a 100 watt amp was a big deal. The need for more headroom manifested into multiple amping.

Todays amps are so powerful and there are so many very capable full range systems it's really not necessary anymore.

Just to be clear though... A satellite / sub combo driven by seperate amps is not bi-amping. That's just running two isolated systems.
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Postby DJ Daddy » Sun Feb 13, 2005 1:29 pm

FDJA wrote:
Just to be clear though... A satellite / sub combo driven by seperate amps is not bi-amping. That's just running two isolated systems.


That is still a bi-amp setup - one signal source setup. Isolated systems would be two stand-alone systems with two separate signal sources.

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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby FDJA » Sun Feb 13, 2005 1:47 pm

The fundamentals of good sound are widely mis-understood.
The basics of good sound are structured like this:

80% of your total sound output is directly related to the loudspeakers.

15% of the total sound output is directly related to the amplification.

5% is input and playback devices, cables, patch cords, etc.

The problem is, that most DJ's have this backwards. They run combinations in which the loudspeaker system is the last thing on their to-do list, with amplifiers taking a back seat as well. This is primarily due to the fact that these are the most expensive components in a sound system, so it's avoided. The sound equipment companies are quick to jump all over the opportunity and sell inexpensive to make EQ's, Sound Expanders, etc as band-aids to a problem that won't go away by itself.


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Just as an additional inner-topic to the whole amps, bi-amps, crossovers subject, here are some super common mis-applications of equipment:

Solid State Cross-Overs in combination with speakers that already have internal cross-over networks.

Too many speakers and not enough amplifiers.

Cheap speakers in combination with great amps.

Cheap amps in combination with great speakers.
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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby MusicDoctorDJ » Sun Feb 13, 2005 11:28 pm

I think you'll notice that the amps in my rack are not 'cheap'!

Carver and Peavey are excellent equipment!

As for those speakers on stands in the picture, they were custom built by my brother for me . . .

He has been a sound engeneer since the early 70's . . .

They are bi-ampable only . . . meaning that they have two plugs on the back . . . one for the Peavey horn . . . the other for the 500 watt JBL woofer!

I also have a pair of high-power Kustom speakers which are switchable between full-range and bi-ampable!

By the way, FDJA . . . we are all mostly DJ's here . . . we are not running sound for concerts!

Lighten up!
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Postby Dave Miller » Sun Feb 13, 2005 11:48 pm

Boy, this thread generated a lot of activity today!

In FDJA's first post today, he talked speakers on one (left or right) channel. 1 speaker being 8 ohms, 2 being 4 ohms, 3 being 2.6 ohms, 4 being 2 ohms, etc. Typical amps should not be run below 4 ohms. Fine.

Those numbers assume that they are all running in parrallel.

If you run two 8-ohm speakers in series, and parrallel that with another two 8-ohm speakers in series, the result is a 4 speaker 8-ohm circuit. However, you'd need a big amp to provide enough wattage to power them.
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Postby TheBartman47 » Mon Feb 14, 2005 1:07 am

FDJA, I must inform you that you are in error on some of your views of sound system engineering. Bi-Amping means splitting the signal into two frequency ranges via an active crossover before being amplified. THATS IT! You can have 4 amps and two subs and two tops, or just four two way speakers or four quasi three way speakers (dual woofer plus horn) and bi amp them.

Also, there is tri-amping, where you have a system like mine, where I split the signal to three parts: subs, woofers, and horns. Eventually, I plan to move up to a quad-amped system. This will be subs, mid bass, mids, and horns. This system will be 57,000 Watts total, and will have EIGHT dual 18" subs, SIX dual 15" mid bass enclosures, and SIX mid/high enclosures with dual 10" speakers and 4" compression driver horns. It will have 24 amplifiers driving all these speakers. It is still a quad-amped system, not a 24-amped system.

Also, bi-amping does NOT mean combining two amps into one speaker! This is a huge electrical nightmare NO NO! NEVER EVER EVER EVER under any circumstances wire two amps to the same driver!!!!!!! This WILL destroy the amps (and probably the speaker as well). Now, you may be confusing the term "bridging", which means to combine the left and right channels of ONE amp together for the purpose of delivering more power, but this is still NOT bi-amping. You can NOT bridge the outputs of two separate amps together.

Not to be tooting my own horn, but I do have a Bachelor's degree in electronics engineering and know exactly what I'm talking about.
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Postby TheBartman47 » Mon Feb 14, 2005 1:12 am

DJ Teddy Bear wrote:If you run two 8-ohm speakers in series, and parrallel that with another two 8-ohm speakers in series, the result is a 4 speaker 8-ohm circuit. However, you'd need a big amp to provide enough wattage to power them.


I just want to point out that although this is technically correct as far as load values go, but for sound reinforcement applications, you do NOT want to wire any speakers in series because this kills the dampening factor. The back EMF (Electro-Motive Force) current will make the series-wired speakers oscilate between each other thus distorting the sound. However, this is actually often a desired effect in guitar amp cabinets, which is why you will often find a 4x10 guitar cabinet wired series-parallel.
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Postby CJ Greiner » Mon Feb 14, 2005 3:08 am

TheBartman47 wrote:...Not to be tooting my own horn, but I do have a Bachelor's degree in electronics engineering and know exactly what I'm talking about.


TOOT TOOT!!! :lol:

Sorry, it had to be said!
And you're right -- bi-amping/tri-amping really only has to do with ranges of frequencies being split from the whole spectrum, and then being amplified by separate amplification circuits.

So, to be clear: :hahaha:
A satellite-sub combo IS bi-amping if the satellite and sub are playing two different frequency ranges, powered by two different amps.
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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby JR » Mon Feb 14, 2005 10:49 am

FDJA wrote:The fundamentals of good sound are widely mis-understood.
The basics of good sound are structured like this:

80% of your total sound output is directly related to the loudspeakers.

15% of the total sound output is directly related to the amplification.

5% is input and playback devices, cables, patch cords, etc.




I'd like to add just one caveat to this. None of the above will amount to a hill of beans unless the operator has an ear for what's playing, and knows what controls to use to compensate for the frequency gains and losses. I agree the equipment quality is very important, but without a good sound man, it might as well remain silent. I'm still learning, and I don't believe I'll ever stop. But if I can develop the talent to make a poor or mediocre system sound good, I'll have no problem when I can afford to join the JBL club.

Just my opinion. I could be wrong :wink:
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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby TheBartman47 » Mon Feb 14, 2005 1:22 pm

Oh, one other thing, you can still bi-amp even if you have only ONE stereo amp. This would be where you run subs on one channel and the tops on the other.
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Re: Ohm's Law, Speaker Wiring Configurations and more...

Postby CJ Greiner » Mon Feb 14, 2005 7:48 pm

TheBartman47 wrote:Oh, one other thing, you can still bi-amp even if you have only ONE stereo amp. This would be where you run subs on one channel and the tops on the other.


Quite true!

I've done that in situations where the room is not setup for the listeners to enjoy stereo, so I run in mono off of one of the amp's channels -- and improve my sound by sending the lower frequencies to a sub via the other amp channel. (Amp is in "Stereo" mode to allow bi-amping).
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self powered speakers

Postby spewie » Wed Jan 04, 2006 5:03 pm

This thread overloaded my circuits. Im currently a club/bar dj and about to go out on my own. Was told by a friend that if I buy 2 self powered speakers - I think he reccomended the JBL ION's ??? that I would be fine just using these and I would not need an amp. ANy feedback on this would be greatly appreciated.
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Re: self powered speakers

Postby dokai » Wed Jan 04, 2006 6:04 pm

spewie wrote:This thread overloaded my circuits. Im currently a club/bar dj and about to go out on my own. Was told by a friend that if I buy 2 self powered speakers - I think he reccomended the JBL ION's ??? that I would be fine just using these and I would not need an amp. ANy feedback on this would be greatly appreciated.


Powered speakers, also called "active" speakers, like the JBL Eons and others, are still amplified. However, the amplifers are built into the speaker cabinet, so you don't need a seperate external amplifier. FYI, most full-range active speakers use multiple amplifiers inside each cabinet, so you end up with a bi-amped or tri-amped system in each speaker cab.

Before you spend your money, check out this thread:

http://start.djgold.com/talk/viewtopic.php?t=520

You can also do a search on "Eon" and get some reviews of them in several of the threads.
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