RTA Measurement Method Differences, House Curves and You!
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- Опубліковано 5 вер 2024
- This video discusses the difference in results of measurement methods and why they should be considered in your analysis of results. Especially when a Target/House Curve is used as your goal.
These all are based on the typical methods I see used. The first is using a microphone placed at multiple locations and sine swept, one-at-a-time, then averaged together to form a singular response. The second is a moving microphone average with you holding the microphone in front of you while in the seated area. The third is like the second, except you are not physically in the seat holding the microphone; you are behind the seat holding the microphone on a boom or by hand.
These methods all result in a different response. The magnitude of differences will vary from situation to situation. But the point is: a difference exists. When trying to match your response to a target curve these differences can have a dramatic effect on the result of your equalization process. It is important to understand these differences exist and understand how different they are in your specific case. I am simply illustrating the fact these differences do exist.
MiniDSP UMIK-1 Microphone I use:
www.anrdoezrs....
Room EQ Wizard (REW):
www.roomeqwiza...
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- Erin
My most recent tuning session in my car used the seated moving mic method with REW's RTA set to use averages. I found the treble to be painful depending on the music in spite of a measured outcome being close to the target curve. I have a better understanding of why that might be because of this video. Thanks.
Glad it was helpful. :)
Thanks Erin. I’m really enjoying your videos and looking forward to your future ones. Very much appreciated mate. Cheers 🍻
Thanks!
Thank you for using the word “behove”.
Very good, clear communication!
Hi Erin, I really lime your videos. Definitely it’s evident the scientific method you apply in all your process. For that reason I’d like to ask your opinion on “target response”.
Background: I have DDRC24 (minidsp 2 in 4 out with dirac live) two full range towers crossed 80Hz LR48db symmetric XO with powered Sub 12 inch, plenty of class D power (TPA3255 DYI) back wall 10cm high density foam 2mx1m and on each ceiling reflection point 5cm 1sq meter high density foam. Same on lateral first reflection and thick carpet between speaker and listening position.
I enjoy thousands (really) measurements with REW looking at freq response and step response.
My finding is that the best clarity is achieved when the first 10-20ms (3-6 meters..) after sound arrival are free of reflections (floor, walls, ceiling,) I mean tamed below 20db . Frequency flat response is important as bass and high extension “But” (I really appreciate your comment on this) even a nice spinorama in a small (reflections between 5ms -10 ms ) live room return poor intelligibility and clarity. I got the highest improvement addressing the first reflections leaving the later ones than by any dac, amp, speaker and dirac. Make sense to you? I see in pro audio , good speakers like kii d&d, grimm, genelec, adam,... address room reflections first by having controlled directivity. And in such studio you have walls far (near field) from the speaker-engineer setup. Are we (all) missing something if we look only at spinorama? Shall we advocate for room treatment to reach the optimal listening?
Could a good engineered speaker (ex: nuemi bs5 sealed, active, digitally integrated with a sub and diraclived) in a “perfect” room return better freq response and impulse response than most multiple ten-thousands high end beryllium, floor standers do today in live rooms?
Thanks in advance
My Best
Lorenzo
Lots of variables here. Firstly, the ideal speaker depends on the person. We know from science that relatively flat on-axis response and controlled dispersion that aligns with the on-axis response, just falling in output, is preferred. But the *amount* of energy off-axis is the gray area, at least in my opinion. Some people prefer less room interaction... a speaker with a higher directivity index. While others prefer a wider directivity (more room interaction). Of course, treatment of the room is also a critical aspect of this as well. If you have a wide dispersion speaker and enjoy the extra apparent source width (ASW) it provides from the side wall reflections then absorbing that may be detrimental to the sound. I truly encourage you to check out Floyd Toole's book on this because all I'd be doing is regurgitating what he says... albeit at a much more simple way because I have nowhere near the intelligence nor experience Dr. Toole does. Not sure if that helps. But hopefully it does. A link (affiliate link) is below for Dr. Toole's book:
amzn.to/3o1Yih5
Or if you don't like doing affiliate links, the title of the book is: Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms
Make sure to get the latest edition (3rd, I believe).
Great content Erin! Thanks!
Very good info... pls make more videos to correct these huge drops and peak in midrange of a car audio setup... Thanks
Noted
thanks Erin.....great help
Awesome Erin, thanks
very informative video! im not aware moving mic method is even a thing. time to do some reading then!
Glad it was helpful. :)
Good stuff, man!
Appreciate it!
Very good presentation Mr Erin...
Can you provide values for the house curve shown in the video.
Thank You for your time and effort. Highly appreciated...🙏🏻
Great video! What is the house curve you used in this demonstration and where can I download it please?
Interesting video. I was surprised at the differences between spatially averaged swept sines and MMM. 5dB is quite a lot! However, I'm curious why you consider "loopback" as a separate category. Why wouldn't you try to keep time relatively accurate (i.e. using a 2-channel interface with loopback, or the timing reference feature with a USB microphone on REW) for individual swept sine measurements within a spatial average?
I considerate it separate simply from the aspect of what people are comfortable with. The majority of measurements I see shared and asked about on forums are taken using the MMA method because it's simple; pink noise and a USB mic get you there. The loopback method requires *a bit* more complexity and understanding. If your goal is simply in-situ response then the MMA method is adequate. Timing/phase is another level of analysis.
Hi you were talking about some other measuring method with rew to set Time aligments and correct phase issues. What is this metod?
ThIs is great Erin, now what are you gonna charge me to tune my car when my install is finished?
I'm thinking.... five bags of skittles and a large kit-kat.
Erin's Audio Corner heck yea and a trip to Rosie’s. We need to exchange numbers. How can I get your email? We just got internet here in Cullman so I’m up town now.
Great video. Not sure what happened at 9:52 though. Lol
Man, me either. Well, I do know... I got ahead of myself and published it before I watched it first. LOL. I fixed it.
@@ErinsAudioCorner Good deal. When I watched it the first time I wasn't sure what exactly happened. I thought maybe you had a stroke while filming. 😂
This video really makes me want to get my mic back out and do another tune session. I knew there had to me differences in measurement techniques but haven't ever tried comparing them.
I learned to tune from Kyle Ragsdale's "How to tune" videos and assumed that method was accurate. After you edited the video and mentioned the instructions for tuning with Dirac makes me want to try a tune without being in the car....or get a DSP with DL.
At the end you said "in general you don't use a house curve"... so what do you use? Tune by ear?
Yes
Problem is : Microphone has no brain ;-)
A lot of humans don’t seem to, either. 🤪
Plus or minus 2 DB is nothing I'm a professional mix engineer I've been doing the stuff for 10 years
WHAT!? 2 dB is nothing? even as little as 1 dB is quite audible to the trained ear, which yours should be if you've you done this for 10+ years.