ericn
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Balance Engineer
Posts: 14,817
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Post by ericn on Jan 11, 2020 12:27:13 GMT -6
The large KEF reference series of the early and mid 80’s was a staple of mastering, classical and acoustic recording. They also had a massive Soffit mounted model that is quite rare.
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Post by Quint on Jan 11, 2020 12:40:03 GMT -6
Incredible post Eric, man that is really informative! Thank you! I decided to spend a few more hours yesterday again trying to tune the KEFs using plugin EQ. I’m attracted to getting them to work because they are full range sealed types. The mic I use is Rode Classic direct into interface preamp.. it’s the flattest “sounding” mic I own and usually works great for this. One thing I finally realized, I get much better results by using a slow sweeping sine and correcting each octave. I also moved the mic around the room. Then afterward I have the ‘flat profile’ dialed (Pretty jagged but +/- 2.5 dB) ..put another instance of EQ and record one speaker playing music. Level match and listen for differences, consider mic response, and adjust using wide EQ so that the recording sounds as close to the reference as possible. End result: what do you know.. references sound like they should.. like they do in the car or anywhere else.. finally! A couple quick mixes and things are translating to the MacBook no issues. For measurement use only pick up a cheap used DBX, Behringer Dayton or Audix calibrated mic, spend a little more send any of the above in to be individually calibrated it will go a long way. When you say send them in to be calibrated, what are we talking about here?
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ericn
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Balance Engineer
Posts: 14,817
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Post by ericn on Jan 11, 2020 13:39:17 GMT -6
For measurement use only pick up a cheap used DBX, Behringer Dayton or Audix calibrated mic, spend a little more send any of the above in to be individually calibrated it will go a long way. When you say send them in to be calibrated, what are we talking about here? They measure your mics deviation from flat and you then input this information into your software. www.cross-spectrum.com/measurement/calibrated_dayton.html
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Post by johneppstein on Jan 11, 2020 16:21:49 GMT -6
There is a different approach by an Austrian AE who cured room modes by sending phase inverted base over a corner loudspeaker into the room. But this is a very complicated approach.
Bag End produces an electronic bass trap that works on this principle, the Bag End E-Trap. It's been around awhile - at least 10 years since I saw it at AES.
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Post by johneppstein on Jan 11, 2020 16:33:25 GMT -6
There’s this misconception that room modes can be “excited” and that volume plays a part. It doesn’t. Room acoustics are linear and any cancellation will occur at every listening level. I think that's a misunmderstanding caused by a semantic problem with people not comprehending the technical meaning of the word "Excited".
Room modes are indeed "excited". They are excited whenever they are fed a frequency at the resonant point. There's no "level variation" involved. And it's not always cancellation. For each reduction of a particular frequency caused by cancellation there is an augmentation at a different frequency. There has to be, since energy cannot be either created or destroyed (outside a nuclear device), it can only be changed from one form of energy to another or shifted in frequency withing the same form.
That's why room modes are also known as "standing waves".
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Post by johneppstein on Jan 11, 2020 16:38:08 GMT -6
The "dbx" measurement mic I have is an Earthworks. I asked them about it and was told (IIRC) that it's actually an M30 with an OEM label on it.
I got it cheap from GC - I'm pretty sure they didn't know what they had and didn't have anyone who understood the significance of the tiny Earthworks logo.
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ericn
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Balance Engineer
Posts: 14,817
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Post by ericn on Jan 11, 2020 17:32:36 GMT -6
The "dbx" measurement mic I have is an Earthworks. I asked them about it and was told (IIRC) that it's actually an M30 with an OEM label on it.
I got it cheap from GC - I'm pretty sure they didn't know what they had and didn't have anyone who understood the significanmce of the tiny Earthworks logo.
Yep My Audix is an MBHO
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