Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
In Reply to: RE: Not quite here yet, bu at least I got ARTA/Limp up and running posted by Mr_Steady on March 16, 2017 at 09:09:33
The measurements is purelly electrical.
The initial one where made manually with a signal generator, a reference resistor and two DVMs. The second, where made with ARTA/LIMP with my computer/soundcard. The similarity then between, strengthen the fact that the measurement where correctly done.
I am a novice in this measure acivities, and not qualified to state what causing that hugh 20Hz peak. My thought where that the cabinette could generate some sort of woofer resonance generating back EMF?
I will try replacing the woofer with an 8 ohm resistor to see what happend.
Those filter schematics would be very much appreciated :o)
I am not sure how to link to several pictures in one post, so I add three separate posts.
First, I have measured the impediance of the complete speaker ones again. But this time from 10Hz upp to 20k.
This was just to make sure that the rising impedans low end cuve actually was a hugh peak. And it was.
Actually, I donīt see this 21Hz peak as a problem, since the Karlson K-15 doesīnt play that low. But as a second thought, a peak of this size must come from some sort of resonance fenomena (back EMF), and hence needed to be tamed.
This was what I ment with acoustically corecting whatīs been seen in my impedance measures.
Since mu bass woofer has a fairly low Q-value, I donīt recognise the transducer itself to resonate, but in combination with the K-15 cab, it propably does.
Could more wool inside the cab help? or could I decease the vent to lower the fb to even those two peaks ?
Next I wanted to replaced the bass woofer with a power resistor (wirewound).
But just to make sure the resistor itself did not caused any inducive phaseshift I first hoked it up to ARTA/Limp
As you can see the resisor measure a fairly straight line, which is good.
Finally, I measured the speaker impedance with the wirewound resistor instead of the bass woofer (the filter intact) and the lines looks allmost as good as the ones you showed me earlyer ;o9
The slight stepp upp below 350Hz is probably caused of the wirewound resistor, being 10 Ohms and not 8.
Clearly all those valleys and peaks are all gone, so the abnormalies must derive from the bass woofer/cab
Post a Followup:
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: