brak
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Posts: 52
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Post by brak on Nov 1, 2020 19:52:53 GMT
Ok.... this might be my OCD over thinking.... I had asked about using my Blue Yeti in a different thread, and was told a mic designed for taking measurements would be best. So here is the issue my mind is seeing...... none of them are USB. Which means I would have to plug the microphone into a pre-amp - which would color the sound. The pre-amp I would be using is a Shure SCM262 Stereo Mixer: Shure SCM262 Stereo Mixer Spec Sheet.pdf (94.71 KB) The two mics I am considering are the Apex 220 Measurement Microphone and the Behringer ECM8000 Ultra-Linear Measurement Microphone. So....... which would end up being better: plugging one of these mics into my pre-amp and into my PC's soundcard, or just plug the Blue Yeti into the USB port of my PC? My "educated enough to be dangerous in this topic" mind is thinking the Blue Yeti would be better - as it has a smaller path. 1: Microphone -> XLR Cable -> Pre-Amp -> LINE Cable -> SoundCard -> Software 2: Microphone -> Software (as the mic, pre-amp, and A/D Converter is all in the same unit) I also have some XLR-USB cables, but I think those only work with dynamics. Thoughts?
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Post by rock on Nov 1, 2020 20:38:51 GMT
If you don't want to buy a measurement mic you can use your omni mic for now to get an idea of what's going on with you room but if you're really serious about measurements, you'll want a measurement mic. IIRC, Ethan has pointed out measurements are not absolutely necessary to get a good sounding room if you follow his general principles. That said, you can verify your setup, troubleshoot problems and fine tune your room with the help of measurements.
I have seen measurement mics that are USB. I just got a flyer from parts-express.com they have a usb mic for $70 #390-808 and an XLR for $50 #390-801 I'm not endorsing these products (I have not used them but they are probably fine), I'm just pointing out these things are out there.
As far a signal chain, I don't think it will make any significant difference either way. Your measurement levels should be well above the noise floor of your system...if it's working correctly:)
You wrote: "I also have some XLR-USB cables, but I think those only work with dynamics."
Regarding the above: dynamic mics are analog and USB is digital so you will need an A/D converter between the mic and your computer...and a preamp in there somewhere too.
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brak
Junior Member
Posts: 52
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Post by brak on Nov 1, 2020 22:46:34 GMT
I have seen measurement mics that are USB. I just got a flyer from parts-express.com they have a usb mic for $70 #390-808 and an XLR for $50 #390-801 I'm not endorsing these products (I have not used them but they are probably fine), I'm just pointing out these things are out there. I'll check those out. Thank you! As far a signal chain, I don't think it will make any significant difference either way. Your measurement levels should be well above the noise floor of your system...if it's working correctly:) I'm not worried about the noise floor, but that of the pre-amp's EQ circuit making the linear mic not-so-linear. You wrote: "I also have some XLR-USB cables, but I think those only work with dynamics." Regarding the above: dynamic mics are analog and USB is digital so you will need an A/D converter between the mic and your computer...and a preamp in there somewhere too. The XLR-USB cables have a built in A/D converter - otherwise they couldn't do their job. If you click on the link you will see the specs of the cables I have. I also confirmed - they only support dynamic, as they can't supply the phantom power condensers need. So will the EQ circuit of the pre-amp muck up the test results?
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Post by rock on Nov 1, 2020 23:42:37 GMT
Sorry, I didn't know an XLR to USB had an A/D, makes sense that it does... but I don't need/have one and I'm not the expert here, I'm just a member like you except I hang out here more than you do. BTW, if you want to know more, read ALL the posts here, not just your own, you will learn a lot more than concerning yourself to your own issues. If everyone did, there would be MANY LESS questions asked! But that's OK, we like to talk about acoustics and that's why we try to answer your questions.
I also don't know about your EQ circuit but you should be able to bypass it, no? If you can't, why do you have a preamp that is not linear? Maybe you want/like the coloration? Nothing wrong with that. But yes, in that case, probably not the best for measurements...but if the coloration is subtle...and all your measurements are through the same path, it probably won't make much difference. If you have read Ethan's material, you'll know if you get your room to within +/- 10db you'll be doing as good as most rooms will ever get.
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Post by Hexspa on Nov 2, 2020 1:07:45 GMT
Any mic is far more inaccurate than a converter. I'm sure there are rare exceptions but I don't think most people consider their converter the weakest link - especially for room analysis.
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brak
Junior Member
Posts: 52
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Post by brak on Nov 2, 2020 3:30:19 GMT
Sorry, I didn't know an XLR to USB had an A/D, makes sense that it does... but I don't need/have one and I'm not the expert here, I'm just a member like you except I hang out here more than you do. BTW, if you want to know more, read ALL the posts here, not just your own, you will learn a lot more than concerning yourself to your own issues. If everyone did, there would be MANY LESS questions asked! But that's OK, we like to talk about acoustics and that's why we try to answer your questions. I also don't know about your EQ circuit but you should be able to bypass it, no? If you can't, why do you have a preamp that is not linear? Maybe you want/like the coloration? Nothing wrong with that. But yes, in that case, probably not the best for measurements...but if the coloration is subtle...and all your measurements are through the same path, it probably won't make much difference. If you have read Ethan's material, you'll know if you get your room to within +/- 10db you'll be doing as good as most rooms will ever get. No problem. The EQ circuit is a standard part of the pre-amp circuit. The only way to "bypass" it would entail opening it up and taking a soldier gun to it. And most pre-amps have EQ circuits, ones without are the exception by far. The only one I can think of myself is a Neve 1272.
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brak
Junior Member
Posts: 52
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Post by brak on Nov 2, 2020 3:33:29 GMT
Any mic is far more inaccurate than a converter. I'm sure there are rare exceptions but I don't think most people consider their converter the weakest link - especially for room analysis. I'm not concerned about the converter, as the Blue Yeti has an internal one (otherwise it wouldn't work) - its the EQ on my pre-amp that I am wondering about.
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Post by rock on Nov 2, 2020 4:12:38 GMT
An EQ you can't bypass? What are you talking about? What is your converter make and model? If you have the manual please send it otherwise I'll search and download it myself just because I can't imagine a preamp that won't. BTW, if there is no actual "BYPASS" button on the EQ, do you do know that setting the controls to zero, AKA "flat", will effectively eliminate the effect of the EQ?
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brak
Junior Member
Posts: 52
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Post by brak on Nov 2, 2020 12:29:05 GMT
An EQ you can't bypass? What are you talking about? What is your converter make and model? If you have the manual please send it otherwise I'll search and download it myself just because I can't imagine a preamp that won't. BTW, if there is no actual "BYPASS" button on the EQ, do you do know that setting the controls to zero, AKA "flat", will effectively eliminate the effect of the EQ? Not talking about the converter, talking about the pre-amp. I posted the make/model and spec sheet in my previous post: The pre-amp I would be using is a Shure SCM262 Stereo Mixer: View AttachmentHere is also the full manual as well: Shure SCM262 Stereo Mixer Manual.pdf (524.09 KB) In regards to "flat" EQ settings - even if you don't have the EQ set to cut/boost, it still will cut/boost, as its still going through the circuits. Like I said, this might be my OCD getting the best of me...... but if we are looking at the details of the freq. response of a mic then it would seem logic would dictate to also look at the freq. response of the pre-amp the mic is being plugged into. So I am wondering which is the "lesser of the two evils".
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Post by Hexspa on Nov 2, 2020 14:00:28 GMT
Ok so you're concerened about the EQ in the preamp messing up your readings?
Forget it. SPL isn't everything so 1-2dB off is fine especially if you don't touch the EQ to change it. Remember you're using a mattress as treatment so let's put everything in perspective. This isn't going to have much if any effect on the decay reading. Yes, EQ introduces ringing but this is going too far down the rabbit hole.
I understand your concern but you're looking for relative improvent. Nulls can be 30dB or so and very narrow. You have what's probably a low and high shelf. I'd say just get a cheap omni and move on.
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brak
Junior Member
Posts: 52
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Post by brak on Nov 2, 2020 14:40:57 GMT
Ok so you're concerened about the EQ in the preamp messing up your readings? Forget it. SPL isn't everything so 1-2dB off is fine especially if you don't touch the EQ to change it. Remember you're using a mattress as treatment so let's put everything in perspective. This isn't going to have much if any effect on the decay reading. Yes, EQ introduces ringing but this is going too far down the rabbit hole. I understand your concern but you're looking for relative improvent. Nulls can be 30dB or so and very narrow. You have what's probably a low and high shelf. I'd say just get a cheap omni and move on. I guess I'm doing a horrible job explaining myself. Let me try to present it in a different way: Option A: Blue Yeti Microphone Omnidirectional (4.5 mV/Pa; 180 - 20,000 Hz): Bidirectional (4.5 mV/Pa; 100 - 15,000 Hz): X/Y Stereo (4.5 mV/Pa; 80 - 15,000 Hz) : Option B: Behringer ECM8000 Ultra-Linear Measurement Condenser Studio Microphone with Shure SCM262 Stereo Mixer Behringer ECM8000: Shure SCM262 [No graphs available] Frequency Response (Ref 1 kHz, channel and master controls centered) MIC/LINE Inputs: 150 Hz to 20 kHz ±2 dB With the Behringer, even though itself has a flat response, would be going through a preamp with 150 Hz to 20 kHz ±2 dB So which of these two options would be better, or is it "6 in one hand, half dozen in the other" situation? Sorry if I wasn't more clear about what I was trying to ask. Hopefully I made more sense this time.
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Post by rock on Nov 2, 2020 14:41:46 GMT
In regards to "flat" EQ settings - even if you don't have the EQ set to cut/boost, it still will cut/boost, as its still going through the circuits. Like I said, this might be my OCD getting the best of me...... but if we are looking at the details of the freq. response of a mic then it would seem logic would dictate to also look at the freq. response of the pre-amp the mic is being plugged into. So I am wondering which is the "lesser of the two evils". Thanks for the download. Just leave the Bass and Treble controls at 12 o'clock and forgetabuotit. Yes, you are over thinking it. Hexspa's advice is right on too.
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brak
Junior Member
Posts: 52
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Post by brak on Nov 2, 2020 14:44:23 GMT
rock lol - we were posting at the exact same time! Like your post came in 15 seconds after /I posted mine!
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Post by Hexspa on Nov 4, 2020 7:20:00 GMT
All I can say is that others have tried to take measurements with mics other than omni linears and then wonder whey their graphs don't make sense.
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brak
Junior Member
Posts: 52
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Post by brak on Nov 4, 2020 20:52:50 GMT
All I can say is that others have tried to take measurements with mics other than omni linears and then wonder whey their graphs don't make sense. That makes sense, but I just don't want to waste money buying a mic which would be compromised due to the pre-amp, making the Blue Yeti actually more accurate at the end of the day. I'm trying to find different USB interface, like the Focusrite Scarlett - but it needs to be Win98 compatible (don't ask....... don't ask lol).
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