# ecm8000 high freq problems



## Kerazul (Nov 9, 2007)

just got my ecm8000 and xenyx802 yesterday.. plugged it in to my x-fi and started messing with it a bit, as it turns out it wont pick up treble frequncies very well. i even tried recording from right in front of the tweeter and it sounded like someone had turned the treble way down. am i doing something wrong here? i tried calibrating according to the measurements i was getting and the treble was like a drill in my head


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## brucek (Apr 11, 2006)

> it sounded like someone had turned the treble way down. am i doing something wrong here?


You have probably forgotten that the XENYX802 is also a graphic equalizer and you haven't zero'd the low, mid, high dials to their detent positions...

Follow the dial positions in the pic below.....









brucek


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## Kerazul (Nov 9, 2007)

they are all at 0.. i have taken a measurement but i'm trying to figure out how to post it


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## Kerazul (Nov 9, 2007)

i was looking at it.. the cable i'm using to go to the computer is coiled (like a telephone cable), could that be making a difference?


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## Kerazul (Nov 9, 2007)

i have tried recording a source from the cd/tape inputs to the computer, so it's not the wire or the computer causing the problem


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## brucek (Apr 11, 2006)

> i have taken a measurement but i'm trying to figure out how to post it


The floppy icon in the lower left corner of the REW graph is a SAVE button. Set the size at 800.

Set REW vertical axis from 45dB-105dB. For full range measurements turn on the smoothing feature..

If you want to test the response of the preamp to see if it has a problem, include it in a loopback cable from line-out to line-in of the soundcard...... Actually you should do that anyway and take a soundcard cal with the preamp in the loop..

brucek


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## Kerazul (Nov 9, 2007)

okay, have taken the measurements with settings as specified...

(image removed)

by the way, thanks for hearing me out and offering assistance.. this is really bumming me out (wasnt free!)


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## brucek (Apr 11, 2006)

For sure the response is dropping off rapidly. You need to establish whether its the ECM or the preamp.

As I mentioned before, you'll have to first measure a cable looped between line-in and line-out of your soundcard (and it should return a perfect flat response of course). Then insert the preamp in that loop using the line-in and line-out of the preamp (as shown below)....










It will have a very good response that will look like this. The red line is the cable and the green line is the preamp....









brucek


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## Kerazul (Nov 9, 2007)

i'll give that test a try when i get enough energy to get the cable together... (you know you're an audiophile when you're still doing this stuff with an abscess!)

i'm beginning to think the error might actually be in myself.. unfortunately i dont have any reference speakers to test on, and it's kind of suspicious that the dropoff showing there is around the same as my crossover frequency. i've been listening to it like that for a long time (calibrated best i could with the radio shack meter) it's hard to tell where the fault is. maybe once i design my next set of speakers i'll have a better picture of what's going on.

thanks again for all the insight and the great resources on this site!


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## fibreKid (Apr 20, 2006)

Just a guess (dip at your x over freq)... is your sub close to your left or right channel? It might be a phase problem. Change the phase on your sub to 180 if it's @ 0 and 0 if it's @ 180. I have a nasty dip exactly (well almost) where yours is and flipping the switch that controls the phase on my sub removed the dip.

good luck
-john


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## Kerazul (Nov 9, 2007)

my sub is crossed over at 50hz (although i think it's only like a 6dB slope) so i doubt that's causing the dip.. i'm not sure what it is.. room resonance? i'll try taking a measurement with the sub switched later on


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## Kerazul (Nov 9, 2007)

well okay, so i was a little less lazy than anticipated... this is with the phase changed.. as you can see that dip is still there but it has done something very unusual to the response down in the sub frequency (also i eqed the upper half a little to bring it up to level.. hopefully the mic isnt lying to me)

(image removed)


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## brucek (Apr 11, 2006)

Limit the lowest horizontal axis to ~15Hz and use a vertical axis of 45dB-105dB. Enter the values into the Graph Limits icon and you can recall them any time....

The dip around 80-90Hz is likely your room.

brucek


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## fibreKid (Apr 20, 2006)

My mistake:devil: I assumed your X over was @ 80.


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## Kerazul (Nov 9, 2007)

well i've been learning a lot...

first.. room accoustics are THE DEVIL

second.. tweeters dont measure so well unless you measure them up close (i guess cause of the narrow dispersion)

third.. (i guess this is the same as the first lol) my speakers measure great up close, but sound like **** in my seating pos


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## avaserfi (Jul 5, 2007)

Kerazul said:


> well i've been learning a lot...
> 
> first.. room accoustics are THE DEVIL
> 
> ...


Room acoustics are just as important as your speakers. The best speakers in the world wouldn't sound it in the average room - things need to be treated end of story rder:.

I am unsure of the speakers you have, but there are a couple possible reasons your speakers don't measure to well/sound great farther away while in reality it is probably a mix of these two: 

1) Room acoustics: Since you are taking measurements in an untreated/under treated room there are many reflections that are interfering with the those that are more susceptible to it [higher frequencies]. Another thing to note is nearly all commercial speakers available that aren't insanely expensive are under braced and thus have cabinet resonance which become more audible due to the room. While due to they type of measurement methods being used this coloration won't show up on your graphs it might add to why you aren't liking the sound as much.

2) Off-axis dispersion: Many speakers, especially their tweeters, don't have the greatest off axis dispersion. This as you said is one reason why they do not measure well from farther away, but also a big reason they might not sound great in your seating position as the colored reflections are reaching your ears at the same time as the on-axis less/non-colored waves. Room treatments can also help with this problem .


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## Kerazul (Nov 9, 2007)

speakers are just some dayton classic 5 1/4 (x2) and a peerless tweeter of which i dont recall exactly that i put together as a first project.. i've got dayton reference drivers now i'm excited to put them together and see how that sounds

my room isnt very ideal i guess... i dont have any serious treatment for sure, but i have put a few things around to at least reduce any major problems (reverb)


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