Home Theater Forum and Systems banner

1 - 9 of 9 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter #1
If you have 2, 3, 8, 57, etc. drivers on a particular channel, how do you make sure they all match each other's output levels? I'm talking about an active system with one amp channel per driver, or at least one channel per crossover band. Do you size the amps to match the different driver sensitivities? Or do you just size the amps to handle the biggest load and then turn down the gain on the more sensitive drivers? I know you don't need the same power on a 1" compression driver as you need on an 18" sub. I'm just curious as to whether there's a standard sort of method for figuring out how much power you do need for each driver. Seems like a waste to build/buy a 200W amp for a driver only to find out I need to turn the gain down to 98W to get the SPL to match the rest of the system.
 

·
Banned
Joined
·
4,838 Posts
If you have 2, 3, 8, 57, etc. drivers on a particular channel, how do you make sure they all match each other's output levels? I'm talking about an active system with one amp channel per driver, or at least one channel per crossover band. Do you size the amps to match the different driver sensitivities? Or do you just size the amps to handle the biggest load and then turn down the gain on the more sensitive drivers? I know you don't need the same power on a 1" compression driver as you need on an 18" sub. I'm just curious as to whether there's a standard sort of method for figuring out how much power you do need for each driver. Seems like a waste to build/buy a 200W amp for a driver only to find out I need to turn the gain down to 98W to get the SPL to match the rest of the system.
First of all, remember that available gain and available output power level are two completely different characteristics of an amplifier, and they can vary widely, although in general a high power amplifier will involve more gain to put it all to work.

Assuming that speaker and driver sizes and efficiencies are relatively well matched in a system, the way to go about what you are asking is to start with matching amplifier output capability to the driver power handling capability. And the next step would be to adjust individual channel gains so the individual drivers and/or speakers all match up in level according to their role in the system. It is rare that a system has every amplifier matched perfectly to every drive, but if you get there, there is really no harm in it.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #3
First of all, remember that available gain and available output power level are two completely different characteristics of an amplifier, and they can vary widely, although in general a high power amplifier will involve more gain to put it all to work.

Assuming that speaker and driver sizes and efficiencies are relatively well matched in a system, the way to go about what you are asking is to start with matching amplifier output capability to the driver power handling capability. And the next step would be to adjust individual channel gains so the individual drivers and/or speakers all match up in level according to their role in the system. It is rare that a system has every amplifier matched perfectly to every drive, but if you get there, there is really no harm in it.
So put a 15W amp on a 15W tweeter and a 100W amp on a 100W mid. Then adjust the gain of each amp to get the two speakers to put out the same SPL at a given volume setting. Correct? And probably avoid pairing a 106 db/W tweeter with an 83 db/W woofer. Or is a more efficient tweeter helpful since it would need less power to produce a given SPL?
 

·
Banned
Joined
·
4,838 Posts
...adjust the gain of each amp to get the two speakers to put out the same SPL at a given volume setting...
You will need pink noise bandwidth limited so that each driver is producing, say, 1 octave of pink noise, in the useful range of the driver. Latest versions of REW include capability to record .WAV file for this.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #6
You will need pink noise bandwidth limited so that each driver is producing, say, 1 octave of pink noise, in the useful range of the driver. Latest versions of REW include capability to record .WAV file for this.
I assume the limited bandwidth is to ensure the test isn't compromised by distortion at the edge of the driver's frequency response.
 

·
Banned
Joined
·
4,838 Posts
I assume the limited bandwidth is to ensure the test isn't compromised by distortion at the edge of the driver's frequency response.
It is to make the measurements equatable for balancing. Sine waves are too hard to work with. If you used full-bandwidth pink noise with a tweeter that covers two octaves and a mid/bass driver that covers 8 octaves, and use that measurement to balance the drivers, the mid/bass driver will be handling 6 dB more sound power and will end up adjusted 6 dB lower than the tweeter. Use band-limited pink noise, limited to within the range of the driver being measured, and the two measurements can be made easily and should be the same SPL.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #8
It is to make the measurements equatable for balancing. Sine waves are too hard to work with. If you used full-bandwidth pink noise with a tweeter that covers two octaves and a mid/bass driver that covers 8 octaves, and use that measurement to balance the drivers, the mid/bass driver will be handling 6 dB more sound power and will end up adjusted 6 dB lower than the tweeter. Use band-limited pink noise, limited to within the range of the driver being measured, and the two measurements can be made easily and should be the same SPL.
Brilliant. Thanks. That's a detail I hadn't thought of or read anywhere else.
 

·
Premium Member
Joined
·
5,798 Posts
This is just like we did my setup with a 114db compression driver, and a woofer that is around 100db. We went with a 25w amp originally for the highs, and a 200w amp for the woofers. I am now building a amp, and the new one e is 50w highs, and 100w for bass. We went this size because it was the only sizes available, but it is still overkill power wize.

Sent from my SM-T550 using Tapatalk
 
1 - 9 of 9 Posts
Top