HOLMImpulse: Measurements in practice

[Altec Best]

I got the test gear up made some adjustments see how it goes Now I took a screen capture of the measurement I sent you already, where is the first reflection in this impulse window I clicked on auto zoom and then captured screen.I want to see if I'm in the right spot on were I was going to set the gate ! The red measurement is 1/6 smoothed.

[Altec Best]

How do I set the gating at 200 Hz when I click on the dotted line I see the freq.res. line move around but I don't see where it says 200 Hz.

[Pano]

If you slide the gate's dotted line toward the left (in the impulse window) you will see the Gate marker appear on the FR plot above. It will move to the frequency that corresponds to the gate time. Watch out, it moves fast! It moves in the opposite direction.

Try it and you'll see.

[Altec Best]

That's just it,the gate marker never appeared ! You know Pano I come to the realization that me and measuring don't mix ! Or my equipment just sucks period.We have found out that it isn't the soundcard,Mic,cable, the only thing left is my computer.I have followed the instructions to no avail what's left.

eBay Listings !!!

1.Behringer ecm8000 Brand spanking new !
2. Mic cable brand spanking new !
3.Mic Stand Brand spanking new !
4.M-Audio Fast Track pro Fairly New eBay special !
5. WT3 woofer tester Brand spanking new !

Get yer bids in folks here they come as soon as my project is done so will they be !!!

My Freak'n Head Hurts !! You know the measurements look fine it is just the distortion in the bass region from 30Hz to 150 Hz and then it drops like a rock ??

[Pano]

Did you check gating under the Options window?

[Altec Best]

Aahh Maybe not. BTW you can scratch that soundcard off that list that has been promised to someone already so No ebay for that!!


I'll give it a whirl again.But that distortion thing is stuck like Chuck and he says he isn't going anywhere.

[John Sheerin]

Can you post a screen shot of the response and distortion? I looked through the thread a bit but couldn't find anything... Have you tried measuring with the mic close to the woofer and decreasing the signal level to see if the distortion goes down? Better, have you tried doing a loop measurement with just the sound card?

[Altec Best]

Originally Posted by John Sheerin

Can you post a screen shot of the response and distortion? I looked through the thread a bit but couldn't find anything... Have you tried measuring with the mic close to the woofer and decreasing the signal level to see if the distortion goes down? Better, have you tried doing a loop measurement with just the sound card?

Loopbacks are perfect flatlines,The frequency Res. are of a Altec 288 on a 511E horn and I tried this one with Mic 2" from front of horn Thanks !!

[John Sheerin]

Looks pretty normal to me. You're hitting 10% distortion a bit below 400Hz on a 500hz horn if I'm interpreting the display correctly (-20dB from the fundamental). Distortion typically will go through the roof when you get down into the roll off of a driver like that. Excursion rises and so does distortion.

[Pano]

You need to try a close (~6") to the woofer measurement to see what's up. When I checked your soundcard, the distortion only came when there was a driver/windoze problem.

If the loopbacks are good, the measurements should be, too. Try a close woofer run - watch your levels - and post it here. Who knows? Maybe there is something odd about the amp or connections.