Any Heil AMT tweeter experts here - any help appreciated

[Music1969]

Hi, I'm just doing a mini project with a friend, to convert Fortura 10 speakers which feature Heil AMT tweeters, to DSP active speakers.

Photos of the passive crossovers attached.

The original passive crossover is at 1800 Hz.

The wiring is direct from power amp to woofer. DAC/Pre controls the volume.

Obviously DAC volume is at minimum to start and I gradually increase volume to run sweeps, till I get to about 75 dBFS.

Lower risk of damaging the drivers with this gradual progression from lowest volume to 75 dBFS.

After measuring the woofer I then swapped over the same speaker cables over to the tweeter.

With microphone 1 inch from the woofer I ran a sweep on the woofer from 20 Hz to 2kHz and it's pretty flat.

I ran a sweep on the tweeter from 1600 Hz to 20kHz and I get small popping sounds... not the sweep sound I was after :-(

I assume there is something different required with wiring the AMT tweeter to the power amp, compared to standard cone woofer.

Does anyone know what I might be doing wrong?

Or should it work with similar wiring to the woofer - except different sweep ranges (which I have done).

Any help appreciated !

 

[Music1969]

Looked at the back of the old pioneer receiver and it says strictly for 8 ohms and up.

Switched to Denon integrated amp rated for 4ohms and i'm back in business.

Happy days... stay tuned for the next update, blown the AMTs with 0 dBFS signal by accident LOL.

I'm wearing earplugs throughout this adventure hehe.

 

[Music1969]

Wow, project turned out great!

There were some tears along the way (almost gave up, but persevered) but the main is is no blown drivers LOL

Used REW to try to find optimal crossover point.

Then used Audiolense to do DSP crossover and room correction convolution.

Very happy with the results.

Roon playing to HQPlayer which is doing all the DSP.

 

[pozz]

Did you figure out what the popping sounds were?

And do you mind posting the FR?

 

[Music1969]

Did you figure out what the popping sounds were?

And do you mind posting the FR?

I only assumed it was due to insufficient power from the Pioneer to power the Heil AMTs. No sweep sounds at all, just those pops.

Same Pioneer was fine with woofer though.

 

[Music1969]

Did you figure out what the popping sounds were?

After much troubleshooting, it was faulty Pioneer AVR. It's going in the trash

 

[Music1969]

And do you mind posting the FR?

With Audiolense doing digital crossovers and room correction, for 2-channel , 3 way system (AMTs, ESS woofers and pair of SVS subwoofers)

DSP crossover is at 1800 Hz just like the original

 

[Music1969]

Using 6 channels of Focusrite Scarlett 18i20 Gen3 to do the 3-way crossover.

Used its built-in mic preamp to do measurements with Earthworks M23 mic.

So using Focusrite ASIO driver for both playback and recording, during the measurements