On recording a loudspeaker voice coil signal

[elif]

What is a high-quality way to record a loudspeaker voice coil voltage?

 

I'm doing a project in which I will be using ARTA to measure the impulse response of a loudspeaker in different in different acoustic environments. The speaker will be driven with 20 W or less, probably by a class-D amplifier with non-grounded outputs. I'll be using the loudspeaker driving voltage for the reference signal. The plan is to use a Focusrite Scarlett 2i4 (gen 1) for both the amp source and mic' input, and record with cardiod and blumlein microphone techniques.

 

• Is there a high-quality active or passive DI that can convert a non-grounded voice-coil signal to a balanced line livel?
  
• Could I use a simple balanced attentuator, maybe 10 kohm, to tap the voice coil and drive and XLR input directly?
  
• Can I rely the anti-aliasing filter of the recording device to filter any class-D out-of-band artifacts before the conversion process?
  

 

TIA,

 

-- bradley

[KuruPrionz]

https://peavey.com/PDFs/Chapter3.pdf

 

Page 7, The Damping Factor, second paragraph. You may already know this or you may find it interesting. It will have an effect on your measurements.

[elif]

Based on this schematic (pdf) for a voice-coil line out, I bought a Jensen JT-11-FL transformer and a 1590B enclosure to house it. This will provide the reference signal for the impulse response measurement.

 

-- bradley

[KuruPrionz]

Based on this schematic (pdf) for a voice-coil line out, I bought a Jensen JT-11-FL transformer and a 1590B enclosure to house it. This will provide the reference signal for the impulse response measurement.

 

-- bradley

 

Looks like a fairly simple build too. Even a not very technical person (like me!!!) could probably figure out how to put that together.

 

This is an interesting project!

[elif]

The project is to measure a set of impulse responses for a Leslie speaker. I measured a set in the 90s using an HP 3562A Dynamic Signal Analyzer. Those impulses were used for a software simulation of what was essentially a close mic'ed Leslie. I now want to load a new set of impulses into the simulation captured using a standard stereo mic'ing technique for L & R. I am hoping it will give a more realistic Leslie-in-the-room presentation.

[KuruPrionz]

The project is to measure a set of impulse responses for a Leslie speaker. I measured a set in the 90s using an HP 3562A Dynamic Signal Analyzer. Those impulses were used for a software simulation of what was essentially a close mic'ed Leslie. I now want to load a new set of impulses into the simulation captured using a standard stereo mic'ing technique for L & R. I am hoping it will give a more realistic Leslie-in-the-room presentation.

 

That is quite the project!!!

 

I do love the sound of a Leslie speaker although I found them challenging way back when I was doing live sound. One of the bands I used to work sound for had one.

At the same time, one of my favorite sonic memories is of playing an electric 12 string guitar while sitting on top of a huge Leslie speaker. I was playing through the speaker and it was swirling all around me, lush and awesome.