Hi,
I hope this piece of information will help some of you to decide what to buy / use, and at the same time, to see if anybody has more helpful information.
Following the feedback posts in the forum, I have bought the Behringer ECM8000 Mic and the Behringer MIC800 MIC preamp. Actually, nobody recommended the Behringer MIC800 but some recommended the Behringer UB802 mixer. I bought the MIC800 because it was cheap and appeared to do the exact job - loudspeaker measurement.
Upon reading the User Manual, I found the following in the MIC800:
I was worried. It appears it employs a first order high pass network at 15 Hz, which can cause inaccuracy in measurement.
Then I was looking at the User Manuals of the UB802 and XENYX802 and hoping they didn't have the filter. I found:
Oh, it is even worse!
I hope I don't have to go through the trouble of reverse engineering the circuit board and replace the filter cap with a much larger value!
Would you be happy with a 1st order high pass at 14Hz for your MIC preamp?
Regards,
Bill
I hope this piece of information will help some of you to decide what to buy / use, and at the same time, to see if anybody has more helpful information.
Following the feedback posts in the forum, I have bought the Behringer ECM8000 Mic and the Behringer MIC800 MIC preamp. Actually, nobody recommended the Behringer MIC800 but some recommended the Behringer UB802 mixer. I bought the MIC800 because it was cheap and appeared to do the exact job - loudspeaker measurement.
Upon reading the User Manual, I found the following in the MIC800:
I was worried. It appears it employs a first order high pass network at 15 Hz, which can cause inaccuracy in measurement.
Then I was looking at the User Manuals of the UB802 and XENYX802 and hoping they didn't have the filter. I found:
Oh, it is even worse!
I hope I don't have to go through the trouble of reverse engineering the circuit board and replace the filter cap with a much larger value!
Would you be happy with a 1st order high pass at 14Hz for your MIC preamp?
Regards,
Bill
Well, depends. For the purpose of trying to use gated measurements to produce a semi-anechoic response graph is definitely doesn't matter. For the purpose of calculating a DRC filter for your loudspeakers it probably doesn't matter (as you loudspeakers probably have no usable output below 30Hz or so). For the purpose of measuring the response of your sixteen 18" driver 10000 watt IB subwoofer and EQing it flat, yeah, you need a new preamp.
Not sure why that is an issue. For low bass response, the room modes will swamp any effect of filtering within the pre-amp.
What slope is employed? If a 6dB HP then even at 15Hz - some attenuation will occur above that.
Reality is - for regular crossover design I would have thought not an issue for you.
Besides unless you get your ECM8000 calibrated, the rolloff on the mic will be probably as great as the rolloff on the pre-amp (ie. you might end up with a combined 12dB+ slope).
PS: I also have a ECM8000 but use an Event EMP-1 pre-amp. The Pre-amp is supposedly flat (+/0.5dB) from 1Hz (?) to 90KHz (when phantom power is used). The EMP-1 preamp has a HP "rumble filter" which you can switch on / off.
The other option would be to bypass?
David.
What slope is employed? If a 6dB HP then even at 15Hz - some attenuation will occur above that.
Reality is - for regular crossover design I would have thought not an issue for you.
Besides unless you get your ECM8000 calibrated, the rolloff on the mic will be probably as great as the rolloff on the pre-amp (ie. you might end up with a combined 12dB+ slope).
PS: I also have a ECM8000 but use an Event EMP-1 pre-amp. The Pre-amp is supposedly flat (+/0.5dB) from 1Hz (?) to 90KHz (when phantom power is used). The EMP-1 preamp has a HP "rumble filter" which you can switch on / off.
The other option would be to bypass?
David.
Quote: In addition, the mono channels (UB1002 and UB1202) are equipped with a steep LO CUT filter (slope at 18dB/oct., -3 dB at 75Hz) designed to eliminate unwanted low-frequency signal components.
That doesn't list the 802 as having that filter and I don't think mine has one. Those manuals are generic for the whole line you so you have to read carefully what is and isn't a feature.
That doesn't list the 802 as having that filter and I don't think mine has one. Those manuals are generic for the whole line you so you have to read carefully what is and isn't a feature.
I built my own, based on Eric Wallins design:
http://mysite.verizon.net/tammie_eric/audio/preamp/preamp.html
I left out the waste of time clipping indicator.
This unit works flawlessly.
http://mysite.verizon.net/tammie_eric/audio/preamp/preamp.html
I left out the waste of time clipping indicator.
This unit works flawlessly.
Nope. Each channel is two drivers in series, all paralleled to give 4 ohms. Clipping the amp will give something like 125dB at 20Hz. This is all for sub 50Hz and movies and is intended to move air with ease, not play stupid loud continuously. If you knew what I paid for the drivers and amp, you'd be shocked. Less than a pair of 8" 'sub' boxes you can get from Harvey Norman. It cost so little, and has the potential to annoy so many, so why not?HiFiNutNut said:
It'll also not take up any floor space.It really doesn't have any more capacity than the corner loaded LABsubs I used for over a year. That system was on probably 15hrs a day for movies and music, and the Police only came once*, and next door only complained to me once too**. The blocks where my house is are small, so they're close together.
* showing off to a friend with Bozo cube HT system.
** during testing when all of next doord crockery was vibrating out of their cabinets.
Good question. I am still awaiting the answer, but meanwhile, I am going ahead with what I have with the MIC800, as I really don't have enough time to do research again. I will see how it goes.
By the way, I built the Walin Jig and found the switch 1 has 20 ohm resistance! Those hopeless Jaycar / Cheap Chinese products. I have to abandon it and am now looking at soldering the Claudio's cables. Somebody in the forum reported the same problem before. I am the second one to confirm it.
By the way, I followed the wiring diagrams in the SW manual to build the Walin Jig. I checked the wirings thoroughly and ensured there was no mistake. I found that the switch positions were not the same as documented. So if you are to build your Walin Jig (without using the cheap switches from Jaycar), be warned that there are errors in the wiring diagrams.
I think Claudio's cables is the way to go.
By the way, I built the Walin Jig and found the switch 1 has 20 ohm resistance! Those hopeless Jaycar / Cheap Chinese products. I have to abandon it and am now looking at soldering the Claudio's cables. Somebody in the forum reported the same problem before. I am the second one to confirm it.
By the way, I followed the wiring diagrams in the SW manual to build the Walin Jig. I checked the wirings thoroughly and ensured there was no mistake. I found that the switch positions were not the same as documented. So if you are to build your Walin Jig (without using the cheap switches from Jaycar), be warned that there are errors in the wiring diagrams.
I think Claudio's cables is the way to go.
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