Inductor core material? Distortion? Audible?

PWRRYD

Well I'll be...  I was a little skeptical but call me a believer!  When I was reading Lasse's thread over at PETT I was unsure if I have ever heard or could hear distortion from a P-Core inductor.  I've used a few P-Cores in past projects and never gave it a second thought. 

My prototype crossovers for the Piers project (Peerless MTM's) use a Jantzen 1.5 mH P-Core inductor unwound to 1.25 mH in the LP woofer filter.  My package from Madisound arrived today.  In it was a pair of their "Sledgehammer" 15 awg laminate core 1.25 mH inductors.  They are $13.70 (about the same price PE sells the P-Core) and they have the same exact DCR as the P-cores, 0.12 ohms.  So I soldered one lead in and use a jumper on the other lead so I can quickly switch between the P-Core and the Sledgehammer.   

At about 80 dB the two inductors sound exactly the same to me.  But when I increase the volume to about 95 dB there is an obvious difference.  I'm not very well versed in audiophile "speak", but the Sledgehammer inductors sound cleaner and like the woofers aren't working as hard.  My Rotel amp (class AB) is only rated for 90 wpc into 4 ohms, so much less than the P-Core's 400 watt rating.

This is obviously not double blind ABX testing and I might be biased since I just spent about $30 on the inductors.  I am going to set up my OmniMic and take some FR and Distortion measurements with both coils at 80 dB and 95 dB and see if there is any difference.

dcibel

Well you say the difference is obvious, I think double blind testing is more beneficial for the less than obvious differences (like this). This makes me feel better about always getting steel laminate cores anyway

Tom_S

I saw that thread too. It was surprising to see the waveform change so drastically when they hit the saturation point. I have wondered if the lighter gauge iron cores, like PE's budget 20G, suffer a similar fate when compared to something beefy like those Sledgehammers.

rjj45

Looking forward to your results.

Wolf

Now try some air-core litz's on your woofers....

I tell you what, it was audible in my experience as well of P vs I.

dcibel

Wolf said:

Now try some air-core litz's on your woofers....

I tell you what, it was audible in my experience as well of P vs I.

That one might call for a double blind test (litz vs solid wire, both air core that is)

PWRRYD

I might not get the measurements done today.  It's supposed to be 38 F here today so I'll be out table sawing some MDF for a project I'm working on (time aligned 3 way).

jhollander

PWRRYD said:

I might not get the measurements done today.  It's supposed to be 38 F here today so I'll be out table sawing some MDF for a project I'm working on (time aligned 3 way).

After building a dust collector I can saw in the basement.  I capture most all the dust but still run a small exhaust fan and wear a respirator.  It's clean enough that I get no complaints...

Wolf

Time aligned via cabinet or ladder-delays?

PWRRYD

Wolf said:

Time aligned via cabinet or ladder-delays?

Cabinet.

PWRRYD

The T-M alignment is dead nuts zero Z-offset.  The T-M to Woofer should be real close to zero (separate bass bin).