multiple drivers and FDW

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Henrik
Posts: 3
Joined: 18 Apr 2020 14:28

multiple drivers and FDW

Post by Henrik » 16 May 2021 12:23

Hello!

My question is about driver linearization in the case of speaker designs with multiple (identical) drivers per channel. Full active design, crossovers / filters done with Acourate - of course :)

The specific example is a 2 way line array of 16 mid bass drivers and 8 HF line source drivers.

- Measuring a single (mid bass) driver is not expedient, since several drivers share enclosure volume -> different behaviour if one or all drivers work on the enclosure volume.
- Running all drivers during the measurent and positioning the mic near to one of the driver membranes does also not seem to be the right way. 5mm, 50mm, 100mm, 200mm, 1m distance between membrane and mic show different measurement results.

So what is the right way for driver linearization with multiple drivers?

I want to make a new setup and tend to position the mic at the listening spot (~3m distance from speakers), what leads to the question about proper windowing of the measurement?
In my understanding, I would choose in FDW very low "Width behind peak" values (or even 0/0 ?) to get rid of most room information. Is that right?

Acourate Wiki says: ( https://www.audiovero.de/acourate-wiki/ ... ent_window )
Bei der Verwendung „Right“ kann zB der Raum ausgefenstert aber eventuelles Prering noch voll erfasst / berücksichtigt werden (die Werte „width before peak“ werden hier wirkungslos).

In my words: Choose "right" (instead of "both sides") for windowing out room information, the values of "width before peak" get without effect. This confuses me, perhaps you can tell me what FDW values correspond to the option "Right"?

Thank you!
Henrik
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UliBru
Posts: 433
Joined: 19 Oct 2019 13:58

Re: multiple drivers and FDW

Post by UliBru » 17 May 2021 09:32

Henrik,

I know about two speaker designs where nearfield measurements are difficult: dipole speakers and multiple drivers.
Thus I recommend to measure the directly at the listening position.

IMO you can use a FDW applied on "both sides". The windowing is thus symmetric to the pulse peak. FDW values below 2/2 do not make much sense.
Indeed at the listening position I always use values in the range 10 to 15.
Stay well tuned
Uli

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Acourate system: JRiver/Roon -> AcourateConvolver -> miniDSP U-DIO8 -> TacT M/S2150 amps -> DIY horn speakers
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