Steve_Roth
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Oct 28, 2011

recommended eq curves for use with non-Bose DSP's

Is it our policy to keep secret the recommended eq settings for Bose loudspeakers? I don't always use a Panaray Controller or ControlSpace on all jobs, and would like a starting point for use with other DSP's. This seems to be a guarded secret, is this by intention?
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rayw-at-bose
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Oct 1, 2008

Re: recommended eq curves for use with non-Bose DSP's

Hello Steve,

Hopefully this will help you replicate Bose EQs.
Open up CS Designer and drag a PM8500 into Project View and then open up PM8500.
Open up (double click) one of the Speaker PEQ blocks and down load whatever type of loudspeaker you want from the drop down loudspeaker menu and all the information you require will be there for you both graphically and alpha-numerically.
See attached example for 802III:

Regards from Australian PSD,

Ray
olesjurdal
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Jan 31, 2013

Re: recommended eq curves for use with non-Bose DSP's

So the speaker files only contain eq? There is no FIR filters etc?
rayw-at-bose
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Oct 1, 2008

Re: recommended eq curves for use with non-Bose DSP's

Hello Ole,

I assume not however I am not definitely sure. You would need clarification from FMH one way or the other.
I was offering this as a starting point for Steve when the required information is not to hand.
Of necessity I have used this method quite often in the immediate past and it has always worked quite well.

Hope this helps.

Regards
Ray
rayw-at-bose
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Oct 1, 2008

Re: recommended eq curves for use with non-Bose DSP's

I should point out Ole that I have not tried this method with RoomMatch loudspeakers, only FreeSpace and Pannary.
Lars_Justesen
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May 20, 2010

Re: recommended eq curves for use with non-Bose DSP's

When using non-Bose DSP, you cannot be sure to obtain the correct EQ when entering the values directly. There can be limitations for the frequency extremities and also in the way the Q of a filter is calculated.

Use your ears and maybe do a comparison measured on signal-level to match the EQ. Smiler
R.Kosman@Bose
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Aug 20, 2008

Re: recommended eq curves for use with non-Bose DSP's

Hello Everyone,

Great discussion!

All of our products use parametric EQ stages, and standard crossovers to achieve the desired response. As Ray points out this information is available within ControlSpace Designer software and you can view it using either the Speaker PEQ within the PowerMatch amplifier, or within an ESP. Simply select "Load Loudspeaker EQ" and you will see the correct PEQ and crossover settings.

A few other notes on this:
  • If you are planning to use this info to apply these EQs in another DSP product, (BSS, Biamp, etc.), You need to measure the transfer function of the ESP first, apply the EQs in the new product, measure its transfer function and create a difference curve from the two. This will tell you how much you need to adjust the EQ stages of the new device to precisely match the desired curve. (there are some good SynAudCon articiles on how to do this, and explaining why different PEQ implementations yield different results)

  • At this time none of our product EQs employ the use of FIR filters. There are numerous pro's and cons to an FIR based approach. In the case of the RoomMatch products there are a class of problems that are typically solved using FIR filters, that we chose to address with acoustic solutions - rather than processing. The result being that we are able to use very minimal EQ to achieve the desired 'out of box' performance both as a module, and as an array.

  • We did, at one time, make a full list available of loudspeaker PEQ settings. However, this has been largely replaced by what is in ControlSpace Designer software. If you are looking for a specific product, or a legacy product, let me know and I can go into my archives and pull it out.

johnr-at-bose
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Oct 2, 2008

Re: recommended eq curves for use with non-Bose DSP's

One more note regarding RoomMatch filters:

There is a 0.396ms delay in the LF portion for the RM models. This value may not be precise based on latency in other DSP products. You will need to make acoustic measurements of a single RoomMatch module to be sure proper phase alignment at crossover. This also means you'll need to make acoustic measurements using a PM8500 or ESP as a reference.

The PM8500 becomes even more cost effective when you count the time to measure and re-measure everything.

JR