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post #1 of 13 Old 02-15-2013, 11:30 PM - Thread Starter
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Hi,
thanks for previous support, here i am with another problem, would like have some expert advice on it.

We are working on a large hall way with 1000 people roaming around (peak)
Now to do announcements we have installed 10 nos of CDB-100LA from JBL, 5 on right and 5 on left.
It is covering full hall for Vocals, but when we play any advertisement or jingles, it sound boring.
As these JBL CBT - 100LA dont have any tweeter or Woofer in it.

We are not bother about LF, we are more keen on HF (tweeter part)

Would like to know, can i add external tweeter sets along with these CBT-100LA,

CBT-100 LA is on 100V line,

I am thinking of putting 2x 8 OHM Tweeter box with stepdown transformer.

These tweeter will not be connected to CBT-100 LA line, they will have their own amp and separate cabling.

Will this work ?
If yes, which kind of tweeter should i select, and also if possible amplifier ??

Please revert on any clarification

Thanks
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post #2 of 13 Old 02-16-2013, 07:53 AM
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Quote:
Originally Posted by Hitesh View Post

Hi,
thanks for previous support, here i am with another problem, would like have some expert advice on it.

We are working on a large hall way with 1000 people roaming around (peak)
Now to do announcements we have installed 10 nos of CDB-100LA from JBL, 5 on right and 5 on left.
It is covering full hall for Vocals, but when we play any advertisement or jingles, it sound boring.
As these JBL CBT - 100LA dont have any tweeter or Woofer in it.

We are not bother about LF, we are more keen on HF (tweeter part)

Would like to know, can i add external tweeter sets along with these CBT-100LA,

CBT-100 LA is on 100V line,

I am thinking of putting 2x 8 OHM Tweeter box with stepdown transformer.

These tweeter will not be connected to CBT-100 LA line, they will have their own amp and separate cabling.

Will this work ?
If yes, which kind of tweeter should i select, and also if possible amplifier ??

Please revert on any clarification

Thanks
FIRST of all you need to give a good bit more usable information-such as the length of the hallway-width of the hallway-exactly where the speakers are mounted-both if horizontal position along the hallway AND the height. Be sure to specify what the height means-to the bottom or center of the cabinet.

Photos would also be really helpful.

I think the idea of adding tweeters is probably a BAD thing.

Do you have any measurements of the existing system? That would be an absolute before ANY other corrective action is considered.

How do you KNOW that you need tweeters? Maybe it is something else that is causing the issue (whatever that is) and adding "tweeters" may not solve the problem-but might actually make it WORSE.

What kind of "tweeter"? How well does the coverage match up with the JBL's? Where are you going to physically place and aim them? Proper speaker design is not a "willy nilly" type of thing that you just "throw more at it". It is quite a science and art.

In MOST cases-people want to simply "add more speakers". In MOST cases that is the WRONG approach. In loudspeaker more is NOT better-it is worse.

FIRST you have to accurately determine what the REAL problem is-THEN look for a solution. How do you know what the solution is-if you don't really know what the problem is. You know what the SYMPTOM is or what you are experiencing-but WHY are you experiencing it?

Now maybe you are looking for something that the speaker is not capable of. In that case-why were those speakers chosen? Maybe you should have made a better choice in the beginning.

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post #3 of 13 Old 02-16-2013, 09:32 AM - Thread Starter
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@Ivan,
thanks for the reply.

1) Hall is approx 300Meter X 15Meter
2) On side of 300 Meter every 50 meter (approx) one JBL CBT 100 LA is installed (5+5)
3) Speakers are installed 12feet above Floor with 15degree angle towards floor.
4) Total 10 JBL CBT 100 LA are driven by Crown CDi4000 on 70V line.
5) Amps channel -1 is service 5 CBT and 2nd channel is serving 5 CBT.
6) I am counting on tweeters after hearing the output from speakers.
7) also these CBT are one way speakers and gr8 for mid
8) Also I have BLU-100 processor
9) there are two computers giving input to BLU-100.
10) two outs comes from BLU-100.,
11) one goes to CDi4000 for CBT
12) 2nd one is for 1000watt local amp
13) one 2nd amp (1000watt, 100v Line Amp) is having 25 nos of 30watt, 2way speakers
14) out put of those 30watt speakers are OK, (due to their quality)
15) I was thinking of adding compression drive of 30watt near each CBT. (with separate cabinet) [30x10=300watts]
16) so i can add one more amp of 500watt and serve those compression drives.

EDIT
Those speakers were suggested by JBL engineers after visiting the place, but that time main focus was on vocals.


Hope above helps solving my problem.
thanks
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post #4 of 13 Old 02-16-2013, 10:14 AM
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Quote:
Originally Posted by Hitesh View Post

@Ivan,
thanks for the reply.

1) Hall is approx 300Meter X 15Meter
2) On side of 300 Meter every 50 meter (approx) one JBL CBT 100 LA is installed (5+5)
3) Speakers are installed 12feet above Floor with 15degree angle towards floor.
4) Total 10 JBL CBT 100 LA are driven by Crown CDi4000 on 70V line.
5) Amps channel -1 is service 5 CBT and 2nd channel is serving 5 CBT.
6) I am counting on tweeters after hearing the output from speakers.
7) also these CBT are one way speakers and gr8 for mid
8) Also I have BLU-100 processor
9) there are two computers giving input to BLU-100.
10) two outs comes from BLU-100.,
11) one goes to CDi4000 for CBT
12) 2nd one is for 1000watt local amp
13) one 2nd amp (1000watt, 100v Line Amp) is having 25 nos of 30watt, 2way speakers
14) out put of those 30watt speakers are OK, (due to their quality)
15) I was thinking of adding compression drive of 30watt near each CBT. (with separate cabinet) [30x10=300watts]
16) so i can add one more amp of 500watt and serve those compression drives.

EDIT
Those speakers were suggested by JBL engineers after visiting the place, but that time main focus was on vocals.


Hope above helps solving my problem.
thanks
If I am assuming (a drawing would be a lot more helpful) that you have speakers on each side facing towards each other? If so -then that is a lot of the problem with bad HF-you have lots of combfiltering going on.

For the dimensions given-it seems as if you have the speakers waayyyy to far apart. I would imagine that there are LARGE dead spots between speakers that are 50M apart and only 12' high.

Are the speakers facing each other or are they facing down the hall? If facing down the hall you need to delay them-which means a lot more gear.

It doesn't matter what the wattage of the compression driver is. You need something that has the sensitivity and power to match up with the JBL's-assuming there is actually a problem with the response of the drivers and not the design of the system.

My feeling is that the design is very wrong with the design-or there is something that I am not understanding about the layout.

Again-do you have any measurements to back up the need for more HF.

Do you have the right processing in the DSP? Is there a "hidden low pass filter" somewhere that you are overlooking?

I would look A LOT harder at other things before jumping into "adding tweeters" and then find out it still doesn't work.

Find the real problem-don't guess!



My "gut feeling" (based on the limited information I have) is that the layout is completely wrong.

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post #5 of 13 Old 02-16-2013, 11:02 AM - Thread Starter
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you can watch this video of the place , main area starts at 1.25min
http://www.youtube.com/watch?v=_2izS3b3Fr8
and sorry size i mention are wrong
hall is 300feet by50feet
and every 50feet one cbt100la is there.

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post #6 of 13 Old 02-16-2013, 01:20 PM
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Quote:
Originally Posted by Hitesh View Post

you can watch this video of the place , main area starts at 1.25min
http://www.youtube.com/watch?v=_2izS3b3Fr8
and sorry size i mention are wrong
hall is 300feet by50feet
and every 50feet one cbt100la is there.

I see a couple of issues. 1: With the speakers facing towards each other you will be getting a good bit of combfiltering-which can "sound" like a lack of HF-but in reality it is a bunch of little notches in the response-making it unclear. Adding tweeters will not fix this-nor will any amount of eq. It is a PHYSICAL problem-and needs to be fixed PHYSICALLY-it CANNOT be fixed with electronics.

It looks like the speakers are away from any boundaries. This is a problem since they have no horizontal pattern control-so the sound simply wraps around to the back. That is a problem becuase now this sound will hit a boundary and bounce back towards the front-and whne it arrives with the front signal-it is out of time-causing even more combfiltering.

These type of speakers (tall skinny column by any manufacturer) need to be mounted against a boundary or they will do "weird things". with the reflections from the rear.

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post #7 of 13 Old 02-16-2013, 08:41 PM - Thread Starter
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^^^
So Can you suggest a better placement of those speakers,
in current setup vocals are very loud and clear.
Also as you can see in clip i uploaded, hall is open from one side of speaker line. (top side of diagram)
I have tested this setup with only one side 5 speaker ON, but power is not sufficient in peak period.

Hope you can suggest something...

thanks
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post #8 of 13 Old 02-17-2013, 07:23 AM
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Quote:
Originally Posted by Hitesh View Post

^^^
So Can you suggest a better placement of those speakers,
in current setup vocals are very loud and clear.
Also as you can see in clip i uploaded, hall is open from one side of speaker line. (top side of diagram)
I have tested this setup with only one side 5 speaker ON, but power is not sufficient in peak period.

Hope you can suggest something...

thanks
A lot of it depends on where you can actually install the speakers. But I would first consider putting them along a single line-or side by side (with space in between).

It does not appear that the people in there are really listening to music-and a system for that type of space would mainly be for announcements. So if you were to get more high freq-would anybody care? or even notice?

With any audio system "upgrade" you have to ask yourself-is it worth it? Does it matter?

Have tried just adding a little HF boost to see what happens?

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post #9 of 13 Old 02-17-2013, 08:16 AM - Thread Starter
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actually announcement part is perfect,
I need good quality high and mid to show my client who gives advertisements. that's why this matters.
will test with one line setup and post an update.
Thanks
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post #10 of 13 Old 02-18-2013, 08:52 AM - Thread Starter
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Tried add HF from BLU-100 (processor) and tested with only one side speaker ON
i think now I dont require extra HF to be added.
Now 2nd step for me is as suggested by you installing speakers side by side
so hoping all problems will gone.

Only one problem which I have no control on is, huge noise created from FANs, they are in every place in this hall
and when they are turn on, audio clarity is gone, even mids are not clear.

Can you suggest something for this.

Thanks
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post #11 of 13 Old 02-18-2013, 05:18 PM
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Quote:
Originally Posted by Hitesh View Post


Only one problem which I have no control on is, huge noise created from FANs, they are in every place in this hall
and when they are turn on, audio clarity is gone, even mids are not clear.

Can you suggest something for this.

Thanks
The problem is signal to noise ration. So you either have to reduce the noise or increase the signal. No way around that.

Noise is one of the biggest things that kills audio quality.

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post #12 of 13 Old 02-19-2013, 09:45 AM - Thread Starter
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@Ivan,
I have one more small connection issue, hope you can give some solution to it.
as i told you, there are FAN installed in Hall area. (amp-1)
Also there are other areas with no noise change . (amp2 to 5).
now when ever those FANs are started I have to increase the signals in Hall area.
which I do from source (computer), after this all over signals are increased,

setup is like
computer gives audio signals to BLU-100 ... Blu-100 out-1 is connected to hall and output-2 is connected to amp2, and amp3/4/5 are looped thru amp2.
I cannot operate BLU-100 on daily basis. so as soon as FANs are turn on we increase the sound level in PC.
which put effect to full setup.

What I am looking at it is, i should have separate gain control for out-1 and out-2.
Is this possible in BLU-100.

Or should i use extra mixers, and how ?
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post #13 of 13 Old 02-19-2013, 04:37 PM
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Quote:
Originally Posted by Hitesh View Post

@Ivan,
I have one more small connection issue, hope you can give some solution to it.
as i told you, there are FAN installed in Hall area. (amp-1)
Also there are other areas with no noise change . (amp2 to 5).
now when ever those FANs are started I have to increase the signals in Hall area.
which I do from source (computer), after this all over signals are increased,

setup is like
computer gives audio signals to BLU-100 ... Blu-100 out-1 is connected to hall and output-2 is connected to amp2, and amp3/4/5 are looped thru amp2.
I cannot operate BLU-100 on daily basis. so as soon as FANs are turn on we increase the sound level in PC.
which put effect to full setup.

What I am looking at it is, i should have separate gain control for out-1 and out-2.
Is this possible in BLU-100.

Or should i use extra mixers, and how ?
I don't know about that processor-but does it have an external control input-such as contact closure input?

If so-then wire a relay to the fan switch so that when the fan is turned on-the relay trips-which sends a closed contact to the relay-which recalls a preset in the DSP with the different volume levels.

You would probably have to have another set of contacts (SPDT relay) so that when the fans turn off the other set of contacts (assuming the center switch is the ground or common) that will recall the original preset.

Another way would be to use a small external signal amp (RDL in the US) and then have a DPDT (wired up as above on the coil side) relay that will bypass the signal amplifier or not.

You just need to make the adjustments for each condition as needed during the proper conditions.

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