TD Function - Driver Polarity Check

PhilActiveAudio
Posts: 55
Joined: 21 Jan 2021 21:51

TD Function - Driver Polarity Check

Post by PhilActiveAudio » 28 Mar 2021 19:16

Hi Uli,

I did not found any documentation about the Driver Polarity Check function in the Wiki, so I am asking.

The TD function - Driver Polarity Check asks for 2 inputs (Lower Sweep Frequency and Upper Sweep Frequency) and returns 2 numbers (xx / yy). I presume that the Lower and Upper Sweep Frequency are the values defined in the LogSweep Recorder while recording a driver (Sweep Start and Sweep End).
Is that correct?

What is the meaning of the 2 numbers given in return? What are the values for a positive polarity and a negative polarity?

Here is the pulse of my mid driver recorded in range 250-25000 Hz and which looks positive to me:
Capture.JPG
Capture.JPG (314.6 KiB) Viewed 2791 times
Thanks in advance.
exaSound e68 DAC ==> class D / Accuphase / class D ==> Jensen Supravox / Arai Radian / Fostex
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UliBru
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Re: TD Function - Driver Polarity Check

Post by UliBru » 29 Mar 2021 12:50

Can you please be so kind and send me the pulse response in question? Thanks.
The polarity calculation is quite tricky and it may also fail. I like to investigate a bit more.
Stay well tuned
Uli

Moderator
Acourate system: JRiver/Roon -> AcourateConvolver -> miniDSP U-DIO8 -> TacT M/S2150 amps -> DIY horn speakers
PhilActiveAudio
Posts: 55
Joined: 21 Jan 2021 21:51

Re: TD Function - Driver Polarity Check

Post by PhilActiveAudio » 29 Mar 2021 21:03

As requested, please find enclosed the pulse response.
Attachments
Pulse96L.zip
(492.12 KiB) Downloaded 127 times
exaSound e68 DAC ==> class D / Accuphase / class D ==> Jensen Supravox / Arai Radian / Fostex
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UliBru
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Re: TD Function - Driver Polarity Check

Post by UliBru » 30 Mar 2021 10:12

Hi Philippe,

thanks for the pulse. It has helped me to improve the algorithm for polarity detection. I have sent you a revised version of Acourate by PM for testing it.
Indeed the detection is quite tricky whereas a visual inspection seems to be simple.
Stay well tuned
Uli

Moderator
Acourate system: JRiver/Roon -> AcourateConvolver -> miniDSP U-DIO8 -> TacT M/S2150 amps -> DIY horn speakers
PhilActiveAudio
Posts: 55
Joined: 21 Jan 2021 21:51

Re: TD Function - Driver Polarity Check

Post by PhilActiveAudio » 30 Mar 2021 21:29

Rapid check of the updated version.
The conclusion is more understandable but I think there still is a problem (check Supravox).

Bass - Supravox 400-2000
Capture - Supravox.JPG
Capture - Supravox.JPG (311.73 KiB) Viewed 2755 times
Mid - Radian 950 PB
Capture - Radian.JPG
Capture - Radian.JPG (293.07 KiB) Viewed 2755 times
Tweeter - Guigue (a bit weird whatever the measurement software is)
Capture - Guigue.JPG
Capture - Guigue.JPG (255.13 KiB) Viewed 2755 times
exaSound e68 DAC ==> class D / Accuphase / class D ==> Jensen Supravox / Arai Radian / Fostex
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UliBru
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Re: TD Function - Driver Polarity Check

Post by UliBru » 30 Mar 2021 22:17

Why do you use a range 250 - 25000 for a bass driver?
If you still have problems you can send me the pulse.
Stay well tuned
Uli

Moderator
Acourate system: JRiver/Roon -> AcourateConvolver -> miniDSP U-DIO8 -> TacT M/S2150 amps -> DIY horn speakers
PhilActiveAudio
Posts: 55
Joined: 21 Jan 2021 21:51

Re: TD Function - Driver Polarity Check

Post by PhilActiveAudio » 31 Mar 2021 08:23

The range for the bass driver is 10-25000 Hz (measurement values) but indeed the XO is at 550 Hz. I will test again with range 10-1000 Hz.
exaSound e68 DAC ==> class D / Accuphase / class D ==> Jensen Supravox / Arai Radian / Fostex
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UliBru
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Re: TD Function - Driver Polarity Check

Post by UliBru » 31 Mar 2021 09:15

Mmh, usually a bass driver is used maybe up to 2 kHz. But up to 10 kHz?

Anyway for polarity check simply measure a driver in a safe range from f1 to f2 even without XO. The limited sweep does the job already. Then use f1 and f2 also in the polarity check.
Stay well tuned
Uli

Moderator
Acourate system: JRiver/Roon -> AcourateConvolver -> miniDSP U-DIO8 -> TacT M/S2150 amps -> DIY horn speakers
PhilActiveAudio
Posts: 55
Joined: 21 Jan 2021 21:51

Re: TD Function - Driver Polarity Check

Post by PhilActiveAudio » 31 Mar 2021 11:40

You are right. The measure was large but as I said, I am using it in the range 10 to 1 000 Hz max as the XO is set at 550 Hz with a steep slop.
exaSound e68 DAC ==> class D / Accuphase / class D ==> Jensen Supravox / Arai Radian / Fostex
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UliBru
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Re: TD Function - Driver Polarity Check

Post by UliBru » 31 Mar 2021 11:50

If the XO is a 550 Hz lowpass then run the polarity check values from 10 to 550 Hz
Stay well tuned
Uli

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