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Old 24th February 2013, 04:44 PM   #21
JMFahey is offline JMFahey  Argentina
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Yes, you can connect any "normal" amplifier (not so sure about a "sub" one, might have a low pass filter permanently in) to a couple extra speakers which will be used as monitors.
Beware that you will have then pointing at a lot of open mics, so use a small amp and raise monitor volume so they can *just* hear themselves a little.
Anyway if the speakers are seated along a conference table they should hear each other without help.
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Old 25th February 2013, 02:26 PM   #22
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Quote:
Originally Posted by JMFahey View Post
Yes, you can connect any "normal" amplifier (not so sure about a "sub" one, might have a low pass filter permanently in) to a couple extra speakers which will be used as monitors.
Beware that you will have then pointing at a lot of open mics, so use a small amp and raise monitor volume so they can *just* hear themselves a little.
Anyway if the speakers are seated along a conference table they should hear each other without help.
Thanks JMFahey, I'll take note, sub amp 45 watts with low volume.

Perhaps I can't understand the following sentence, kindly help...
QUOTE:-In fact, any cheap 100W / 4 ohms (obviously mono) powered mixer box will probably be enough to drive all 18 speakers. QUOTE
My QUESTION:-SHOULD I CONNECT TO 4 OHMS AMP OUTPUT WITH 2 CHANNEL IN PARALLEL, WHEN YOU SPECIFIED 100W / 4 OHMS OBVIOUSLY MONO OR I CAN GO WITH 2 CHANNEL 8 ohms CIRCUITRY?
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Old 25th February 2013, 04:22 PM   #23
JMFahey is offline JMFahey  Argentina
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Your original idea of using a stereo amplifier , one channel to each side of the room, is fine.
2 8 ohms channels are perfect, of course.

What I commented is that given the size and type of use, probably even a simple 100W box mixer will be able to power the full room.
Based on it being a "conference" system, with a little background music thrown in.

Now, if it were a Dance type meeting, such as a Rave place or something, then you would need *much* higher power and big Pro type cabinets .... only it does not seem to be the case.
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Old 26th February 2013, 07:04 AM   #24
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Hi, JMFahey,
You know I did a home test with 18 speakers connected on my Amp 2 channel Hi-Fi output 32 watts per channel ! ! with volume level suffuciently ajusted about JUST an haft an hour and was ok.

Tell me can I increase the size of mains cables as to maintain the load as far as possible to 8 ohms, At this time I found the resistance of the main cable ONLY (24meters long) to one channel is 1.4 ohms (silver strand) and .9 ohms (copper
strand) ?

No Dance type meeting, no Rave place ! Just music like classic at 5 times X 3min per day.

For choice of amplifier, please guide me between following:
1st:- InterM PA6000 Rated Output (RMS) 240W 4/8/100v
2nd: Ahuja MXA3500 350W RMS
3rd: Ahuja TZA4000 200 watts x 2 channels
4th: Ahuja TZA2000100 WATTS x 2 channels
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Old 26th February 2013, 07:51 AM   #25
JMFahey is offline JMFahey  Argentina
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Nice you tested and confirmed what I suggested.

Forget silver wire, of course.
It's a Sound System installation, not a Jewellry contest
Copper is best (maybe that's why it's used in 99.9999% of installations ) and 0.9 ohms , in series with a 24 ohms column speaker (the one which will actually be 24M away) is nothing.

Even if it were an 8 ohms speaker it's inaudible, go figure.

As of the PA amplifiers, any of them is enough.

I see you chose not "Band PA" amplifiers but solid robust "Commercial" amplifiers.
They are meant more for fixed installations than for a "band on a go".
Fine with me.

You will choose based on what features you need and price.

I would go with the brand which guarantees the best servicing.

The Ahuja impressed me with their capability of running from 2 or 3 car batteries if needed, and all of them have 70V and 100V speaker output, which in the future allows you to cover huge areas if needed (adding 70/100V transformers to each speaker, of course).
You won't need that in a 15x15m room, but it's nice to know you can expand in the future.

Personally I'd go for the "large" Ahuja if possible ($$$$).

Only funny spec (although quite common in this kind of amplifiers) is that the Mic input is unbalanced.
Not bad if the microphone cables are not longer than 15 or 20 m. at most.

The InterM one has XLR balanced connectors which allow you to use microphones with, say, 60 m. cables.

Don't know, *you* tell me what you will use.
Inside that room, all are fine.
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Old 26th February 2013, 12:23 PM   #26
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Hi JMFahey,
QUOTE Nice you tested and confirmed what I suggested. QUOTE
THANKS FOR ADVISE

QUOTE Copper is best (maybe that's why it's used in 99.9999% of installations ) and 0.9 ohms , in series with a 24 ohms column speaker (the one which will actually be 24M away) is nothing.
Even if it were an 8 ohms speaker it's inaudible, go figure.
Tell me can I increase the size of mains cables as to maintain the load as far as possible to 8 ohms...
At this time I found the resistance of the main cable ONLY (24meters long) to one channel is 1.4 ohms (silver strand) and .9 ohms (copper strand) ? QUOTE

Once again I TESTED (at home with 32 watts HI-Fi) A CHANNEL WITH 24 METERS LONG (30/0.25mm) and I SET THE VOLUME AT HAFT to have ''OUR'' best required volume level, thence I double this 24meters (30/0.25 x 2) and the ohms test shown 8.2ohms for this channel with 9 speakers connected, tested on sound I HAD ONLY TO SET THE VOLUME AT QUARTER OF VOLUME SCALE.

So Is it necessary to upgrade the wires on that part ? Please advise


Don't know, *you* tell me what you will use.
I w'll see the association with Inter PA 6000 and Ahuja PA 4000 ?
What do you think about Amplifier Malan-shi OK 05 (500 watts x 2 channel) Hi-Fi, ?

I will install an earthing system to protect equipment: hope I will reach below 1 ohms...

Sincerely, I greatly appreciate your marvelous and intelligent advise, find no sophisticated words to say how much YOU have been "way finding" but I only want to say thanks and may God add years of life to your personality.
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Old 26th February 2013, 01:59 PM   #27
JMFahey is offline JMFahey  Argentina
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Quote:
Once again I TESTED (at home with 32 watts HI-Fi) A CHANNEL WITH 24 METERS LONG (30/0.25mm) and I SET THE VOLUME AT HAFT to have ''OUR'' best required volume level, thence I double this 24meters (30/0.25 x 2) and the ohms test shown 8.2ohms for this channel with 9 speakers connected, tested on sound I HAD ONLY TO SET THE VOLUME AT QUARTER OF VOLUME SCALE.
So Is it necessary to upgrade the wires on that part ? Please advise
You already tested that you have ample volume even with a home Hi Fi type amplifier, so the wiring and speakers you have are fine.
If you buy a "big" amplifier, it's thinking of future use in much larger places or in open space.
For voice and some background music in a closed 15 x 15 m. space you don't need much.
Specially because you spread speakers very well to cover smoothly all the room.
People usually worry too much about the amplifier and don't think much about the speaker and room acoustics, while the real problems lie there.
You will sound very good.
Quote:
I w'll see the association with Inter PA 6000 and Ahuja PA 4000 ?
What do you think about Amplifier Malan-shi OK 05 (500 watts x 2 channel) Hi-Fi, ?
The amps you mentioned in the first list were all fine.
You choose based on number of microphone inputs, whether being able to be powered by batteries is important, etc.
Power is more than enough with any of them.
I like very much the Ahuja "built in UPS" so with 2 or 3 car batteries you are protected from power cuts.

And, thanks, you'll make me blush.
Don't overthink this: you already have the speakers, know they work well and are easy to drive, have found a proper wire size, just choose the amp and start thinking about microphones, their wiring, what your music source will be, etc.
For monitoring, *any* amplifier (even your current Hi Fi amp) will do.
In the furture, post a couple pictures of your installation.
Good luck.
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Old 27th February 2013, 08:03 AM   #28
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Hi FMFahey,
I'll not miss to post couple pic...Thanks for all, will be back soon, Sir FMFhey...
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