Post Your Frequency Response Curve!

[Ron Resnick]

It has been suggested to me that the real time analyzer software I am using is not dependable. I am prepared to download and use Room EQ Wizard.

The only glitch is that my computer stuff is 100% Apple focused. so I guess I have to buy a PC laptop or a PC tablet just to use the free REW.

In the experience of our REW users is it easier to use REW on a PC laptop or a PC tablet, or it just doesn't matter?

 

[Ron Resnick]

Also I have my high class, very flat frequency response Earthworks QTC40 microphone. I have a power supply to provide phantom power to that microphone, but I now realize that I need an external preamp as well.

So I might start over there too and just order UMIK-1 or UMIM-2 with calibration file.

Any thoughts on these microphone options?

 

[tony22]

Also I have my high class, very flat frequency response Earthworks QTC40 microphone. I have a power supply to provide phantom power to that microphone, but I now realize that I need an external preamp as well.

So I might start over there too and just order UMIK-1 or UMIM-2 with calibration file.

Any thoughts on these microphone options?

Ron, unless you’re doing JA type measurements, IMO a UMIK-1 (get the 1, not the 2, there’s stuff online describing why - although either will work fine really) with a cal file is sufficient for REW and room measurements.

 

[Ron Resnick]

Ron, unless you’re doing JA type measurements, IMO a UMIK-1 (get the 1, not the 2, there’s stuff online describing why - although either will work fine really) with a cal file is sufficient for REW and room measurements.

Thank you!

I see that an Apple laptop with a current version of OS will run REW. So I might have to get a new Apple laptop just for REW just to stay in the Apple ecosystem.

 

[Ron Resnick]

Thank you! I ordered a UMIK-1 and a cheap, lightweight boom mic stand. (The high quality tripods that I use for my video camera are a little heavy and unwieldy for this purpose, I think.)

I was able to download REW on my early 2015 Apple laptop.

 

[ecwl]

I see that an Apple laptop with a current version of OS will run REW. So I might have to get a new Apple laptop just for REW just to stay in the Apple ecosystem.

Yes. I use my M1 MacBook Pro for REW.

But my take often is that we shouldn't have to buy new gear if our current ones work.

Maybe if you can tell us what MacBook and which iPad you currently have, we can find a better software alternative for you.

I have to admit, for most simple things, my dealer and I just use the iPad and AudioTools. Only for the really complicated sophisticated measurements would I resort to REW with the MacBook Pro.

 

[morricab]

Thank you! I ordered a UMIK-1 and a cheap, lightweight boom mic stand. (The high quality tripods that I use for my video camera are a little heavy and unwieldy for this purpose, I think.)

Now I have to get a basic Apple laptop, I guess.

Get a used Behringer DEQ 24/96 and calibrated mic from Behringer. Cheap, accurate and no computer needed. Not highest resolution but 1/6th octave is really good enough for most purposes. It’s what I use and it’s quick and easy to setup. You also use the EQs for bass mode reduction at least to see the effects of removal.

 

[Ron Resnick]

Get a used Behringer DEQ 24/96 and calibrated mic from Behringer. Cheap, accurate and no computer needed. Not highest resolution but 1/6th octave is really good enough for most purposes. It’s what I use and it’s quick and easy to setup. You also use the EQs for bass mode reduction at least to see the effects of removal.

Thanks, but I'm tired of futzing around and getting results. I want to do it in an industry standard (at least for nonprofessionals) way this time.

I'll bite the bullet and learn to use REW.

 

[Alrainbow]

Does anyone consider to remove one set of speakers in the room first ?
there both not little box speakers
I get possible why Ron don’t and why he tried his other woofer towers
Ron asks honest questions and as who he is many try to help
but most all tip toe around the obvious
taking measurements is needed but like most things in this hobby
unless your are able to understand what’s shown and the many methods to achieve them
It’s a shit show in the dark
I’m sure Ron is aggravated for asking by now hahaha
and im tapping out on this topic

 

[Ampexed]

If you have a microphone calibration file like all UMIK microphones provide, that's all you need to get an accurate measurement.

FWIW, this is my latest listening position response plot.

 

[tony22]

Thanks, but I'm tired of futzing around and getting results. I want to do it in an industry standard (at least for nonprofessionals) way this time.

I'll bite the bullet and learn to use REW.

Good for you, Ron. There’s a bunch of us here who’ve used REW for year. Help is always around if needed, and John Mulcahy has a dedicated forum on AVNirvana.

 

[Mcsnare]

Also I have my high class, very flat frequency response Earthworks QTC40 microphone. I have a power supply to provide phantom power to that microphone, but I now realize that I need an external preamp as well.

So I might start over there too and just order UMIK-1 or UMIM-2 with calibration file.

Any thoughts on these microphone options?

That’s a solid response test mic. Don’t forget to take a lot of samples in various positions close to your listening spot. Then average the plots.

 

[luca.pelliccioli]

A few weeks ago I went down the same REW rabbit hole, Ron. MacBook Pro and Umik mic calibrated are ok. I use 1/12 smooth and you will find Spectrogram and waterfall graphs usefule.

Enjoy!

Here’s my results comparing 3 different bass traps placements last week (sorry for different scale, I’m on iPad now, need to take new pics to uniform different views)


Here where I started 3 months ago:

 

[StreamFidelity]

It has been suggested to me that the real time analyzer software I am using is not dependable.

Hi Ron,

if you are looking for dependablity, a microphone with a microphone preamp is better.

With USB microphones, there can be a drift in the timing. This is because they have their own ADC (analogue-to-digital converter). This means that two independent clocks are used for playback and recording. This usually leads to sub-optimal measurement results because the pulse responses exhibit time stretching/compression effects. This is because the synchronisation of these two clocks is very important for a pulse measurement that also takes the time domain into account. The first clock is located in the DSP and generates a log sweep with a precisely defined sample rate. E.g. 48,000 samples per second. The clock in the USB micro, for example, is slightly slower and has 48,001 samples per second in the same period. With a 60-second sweep, that's already a difference of 60 samples in length! There is something like clock drift correction in room correction programmes. But you have to measure and calculate this drift first.

An analogue microphone with a microphone preamplifier avoids all these problems. Because there is only one clock, namely the one in the USB audio interface. An inexpensive and good DAW is for example UR12 | Steinberg

This would be the measurement setup:

Source: How to measure your room and speakers – Grigg Audio Solutions

Warmest regards

Gabriel

 

[sigbergaudio]

A few weeks ago I went down the same REW rabbit hole, Ron. MacBook Pro and Umik mic calibrated are ok. I use 1/12 smooth and you will find Spectrogram and waterfall graphs usefule.

Enjoy!

Here’s my results comparing 3 different bass traps placements last week (sorry for different scale, I’m on iPad now, need to take new pics to uniform different views)
View attachment 131853

Here where I started 3 months ago:
View attachment 131858

Is this measured in the listening position? Looks pretty light on bass?

 

[luca.pelliccioli]

Is this measured in the listening position? Looks pretty light on bass?

Don’t know what I made wrong, my bad! This is the last measurement from listening position.

With and without a bass trap on the right corner.



The room is 12x18x8 - here below a recent pic

 

[Tangram]

Thank you!

I see that an Apple laptop with a current version of OS will run REW. So I might have to get a new Apple laptop just for REW just to stay in the Apple ecosystem.

I run REW on an ancient Macbook that we bought my son in Grade 7. He's three years out of undergrad so it's about 12 years old. FWIW, I recently had an acoustics consultant in who used a Dayton real-time analyzer that was incredibly useful when integrating my subs (which have DSP). Being able to see the changes on the screen as they are made is very effective and efficient.