REW 101 help

[muslhead]

I recently received my pair of Buchardt a500 speakers and wanted to do a sweep measurement to see if they measure as they sound. I have only used REW once before so i have not gotten the setup down pat but my results were such that something is wrong. Likely not the speakers but me so i am going through the setup process one more time. One of the first questions out of the gate is how to position the mik. The manual suggests when testing the low end (20-200) the mik should be pointing up and use the 90deg cal file. When testing above that, it is recommended you point the mik at the speaker (ear level). What are you to do if you are testing the full range 20-20k? i assumed pointing at the speaker but thought i would ask to insure i can eliminte this from the cause of my screwy looking sweep curve
TIA

 

[PierreV]

the cause of my screwy looking sweep curve
TIA

Usual culprits are the room, the room and, the room
Can you show your curve?

 

[muslhead]

Usual culprits are the room, the room and, the room
Can you show your curve?

So, are you saying its likely the room?
What? you think i am a glutton for punishment. NFW am i going to post my curves. At least not until i check and recheck my work. I have been here long enough to know that without more checking i am nothing more than fresh meat for those on the forum who are into belittling those posting dumb questions

BTW, you are right regarding the room because what i hear matches my results but the magnitude of what i am getting in my sweeps makes no sense (a 20 db drop from peak to trough across the spectrum)

Now can you just answer my questin dammit

I will post the results once i make any adjustments to the setup and insure my head is properly remoed from my anal oriffice.

 

[PierreV]

I will post the results once i make any adjustments to the setup and insure my head is properly remoed from my anal oriffice.

Well, then the other thing is the measurement distance. My own measurements, which I posted but can't find now, are markedly different from what you usually see here, in part because I still have my head in the same location as yours, in part because I measure at my listening distance and not at the 1m (or 2m) "standard". Plus, obviously, I don't own a klippel

 

[muslhead]

Well, then the other thing is the measurement distance. My own measurements, which I posted but can't find now, are markedly different from what you usually see here, in part because I still have my head in the same location as yours, in part because I measure at my listening distance and not at the 1m (or 2m) "standard". Plus, obviously, I don't own a klippel

I did not know about the distance thing thanks for bringing it up. I was measuing 15-20ft away as that is where the speakers are centered to. Its a big, open room with huge ceilings and no real absorbtion so, i am confident the room will play a huge part of what i am hearing/seeing.

 

[RayDunzl]

BTW, you are right regarding the room because what i hear matches my results but the magnitude of what i am getting in my sweeps makes no sense (a 20 db drop from peak to trough across the spectrum)

That's normal.

Maybe mild.

1/48th smoothing. Both speakers playing, at the listening position, no EQ applied.

 

[muslhead]

That's normal.

Maybe mild.

1/48th smoothing. Both speakers playing, at the listening position, no EQ applied.

View attachment 126741

Thanks, i was using 1/6 smoothing. Now, what about the mik direction --------- Pretty please

 

[RayDunzl]

Thanks, i was using 1/6 smoothing. Now, what about the mik direction --------- Pretty please

I point my mic at the phantom center berween the speakers from what would be the phantom center of my head at the couch.

With EQ, and 1/6th smoothing:

The 48Hz dip is an asymmetrical rear of the room standing wave phase cancellation that I don't really hear, and didn't know I had, until measured.

I did hear the excessive bass around it.

Knocking out the bass peaks is all I do, sometimes.

I hear and can be annoyed by response peaks, little troughs may not be noticed as faults.

I'm flexible.

 

[GDK]

BTW, you are right regarding the room because what i hear matches my results but the magnitude of what i am getting in my sweeps makes no sense (a 20 db drop from peak to trough across the spectrum)

That's why so many people here harp on about room correction. That sort of thing is not at all unusual in a room. Here is my uncorrected and corrected results (L and R, I think these were done at 1/12 smoothing):

 

[alex-z]

I did not know about the distance thing thanks for bringing it up. I was measuing 15-20ft away as that is where the speakers are centered to. Its a big, open room with huge ceilings and no real absorbtion so, i am confident the room will play a huge part of what i am hearing/seeing.

What you hear will be almost entirely the room. Huge decay times and lots of reflection. Big rooms have a lot of potential if treated, but usually sound poor by default. If absorption isn't an option, moving the listening position closer to the speakers should improve the situation.

 

[muslhead]

What you hear will be almost entirely the room. Huge decay times and lots of reflection. Big rooms have a lot of potential if treated, but usually sound poor by default. If absorption isn't an option, moving the listening position closer to the speakers should improve the situation.

There is no listening position in this room. It is a family, kitchen and dining room. Its about 35' x 35' and has 15 fit ceiling which expand to 30 towards the back of the room (away from speakers). In addition to add to this mess, the only place i can put the speakers is up against a glass wall (dont ask as its the only reasonably safe place away from my mischievous cats)
I selected a point in the room that i wanted the sound to be the listening point and the corrected from.
Because of its size any point selected will be off axis to 95% of all listening positions.
But i knew this and why i am just focusing on that one spot.
I was attempting to remove any errors cause by me as i have a large enough problem (room) without me adding any to it.

 

[muslhead]

Thanks to all that replied with the help. I will do some testing with the recommended adjustments and post for comment.

 

[Hipper]

I did some measurements and notes on mic positions and other things. I posted them somewhere on this site but can't find it so will post here. I was attempting to measure my speakers plus room and measured the speakers individually.

What Difference does a Person Sitting in the Chair Make?

1/24 smoothing, full range, purple being with me in the chair.

Oh! The right speaker had broadly the same effect, notably the increase from 600-1500Hz

What Difference Where You Stand When Taking Measurements?

I always stand behind my equipment in the back left hand corner so I compared that with standing on the right back corner, and standing behind the chair.

No smoothing. Purple is left, green is centre, brown is right.

It doesn’t seem to make a massive amount of difference

What Difference Where You Point the Microphone?

Brown - at my ear pointing to speaker
Green - in the middle pointing at speaker
Purple - in the middle pointing down the middle of the room
Red - in the middle pointing upwards
Turquoise - in the middle pointing downwards

The first FR is up to 500Hz, no smoothing. The second is full range at 1/24 smoothing.

The makers of my Earthworks microphone say to point it to the source, but I’ve seen other recommendations to point mics up or down. It seems to make a bit of difference in actual measurements.

I suppose all we can do is be consistent.

What I do now

I place the microphone at my ear level and central position pointing it at the phantom image. I listen on my own so aim for a good image at my listening position (LP). I understand that if you are measuring for a number of LPs you might find it better to use Moving Mic Measurements (MMM) - I've never done this but there are discussions on here somewhere.

If you want to measure an individual speaker the ideal would be to take it outside as DEQX used to suggest for their speaker calibration method. That is to avoid the influence of the room. I understand though that both DEQX and MiniDSP now use some sort of algorithm to try and compensate for reflections etc. but how accurate that is to individual circumstances I don't know. Maybe REW has something like this too.

I wouldn't get to stuck on measurements. Use a consistent measuring method, use the measurements as a guide to get the best sound but in the end your ears listening to music must be the judge.

 

[muslhead]

I did some measurements and notes on mic positions and other things. I posted them somewhere on this site but can't find it so will post here. I was attempting to measure my speakers plus room and measured the speakers individually.

What Difference does a Person Sitting in the Chair Make?

View attachment 126819

1/24 smoothing, full range, purple being with me in the chair.

Oh! The right speaker had broadly the same effect, notably the increase from 600-1500Hz

What Difference Where You Stand When Taking Measurements?

I always stand behind my equipment in the back left hand corner so I compared that with standing on the right back corner, and standing behind the chair.

View attachment 126823

No smoothing. Purple is left, green is centre, brown is right.

It doesn’t seem to make a massive amount of difference

What Difference Where You Point the Microphone?

View attachment 126824

View attachment 126825

Brown - at my ear pointing to speaker
Green - in the middle pointing at speaker
Purple - in the middle pointing down the middle of the room
Red - in the middle pointing upwards
Turquoise - in the middle pointing downwards

The first FR is up to 500Hz, no smoothing. The second is full range at 1/24 smoothing.

The makers of my Earthworks microphone say to point it to the source, but I’ve seen other recommendations to point mics up or down. It seems to make a bit of difference in actual measurements.

I suppose all we can do is be consistent.

What I do now

I place the microphone at my ear level and central position pointing it at the phantom image. I listen on my own so aim for a good image at my listening position (LP). I understand that if you are measuring for a number of LPs you might find it better to use Moving Mic Measurements (MMM) - I've never done this but there are discussions on here somewhere.

If you want to measure an individual speaker the ideal would be to take it outside as DEQX used to suggest for their speaker calibration method. That is to avoid the influence of the room. I understand though that both DEQX and MiniDSP now use some sort of algorithm to try and compensate for reflections etc. but how accurate that is to individual circumstances I don't know. Maybe REW has something like this too.

I wouldn't get to stuck on measurements. Use a consistent measuring method, use the measurements as a guide to get the best sound but in the end your ears listening to music must be the judge.

Excellent help, thanks

 

[Frgirard]

I did some measurements and notes on mic positions and other things. I posted them somewhere on this site but can't find it so will post here. I was attempting to measure my speakers plus room and measured the speakers individually.

What Difference does a Person Sitting in the Chair Make?

View attachment 126819

1/24 smoothing, full range, purple being with me in the chair.

Oh! The right speaker had broadly the same effect, notably the increase from 600-1500Hz

What Difference Where You Stand When Taking Measurements?

I always stand behind my equipment in the back left hand corner so I compared that with standing on the right back corner, and standing behind the chair.

View attachment 126823

No smoothing. Purple is left, green is centre, brown is right.

It doesn’t seem to make a massive amount of difference

What Difference Where You Point the Microphone?

View attachment 126824

View attachment 126825

Brown - at my ear pointing to speaker
Green - in the middle pointing at speaker
Purple - in the middle pointing down the middle of the room
Red - in the middle pointing upwards
Turquoise - in the middle pointing downwards

The first FR is up to 500Hz, no smoothing. The second is full range at 1/24 smoothing.

The makers of my Earthworks microphone say to point it to the source, but I’ve seen other recommendations to point mics up or down. It seems to make a bit of difference in actual measurements.

I suppose all we can do is be consistent.

What I do now

I place the microphone at my ear level and central position pointing it at the phantom image. I listen on my own so aim for a good image at my listening position (LP). I understand that if you are measuring for a number of LPs you might find it better to use Moving Mic Measurements (MMM) - I've never done this but there are discussions on here somewhere.

If you want to measure an individual speaker the ideal would be to take it outside as DEQX used to suggest for their speaker calibration method. That is to avoid the influence of the room. I understand though that both DEQX and MiniDSP now use some sort of algorithm to try and compensate for reflections etc. but how accurate that is to individual circumstances I don't know. Maybe REW has something like this too.

I wouldn't get to stuck on measurements. Use a consistent measuring method, use the measurements as a guide to get the best sound but in the end your ears listening to music must be the judge.

Start by measure speakers in mono. You will make a great step to the light.

Before you can read the link below.

https://gearspace.com/board/studio-building-acoustics/469574-measuring-room-acoustics.html

The Frequency response curve is a little part. Waterfall, Etc are more important than the Frequency curve.

 

[Hipper]

I agree that Waterfall, and Spectrograms, are useful, as are Phase, Decay times and other graphs. However it is not so easy to change these directly whilst changing the frequency response (FR) is easy and understandable. Reducing and smoothing the decay times across the frequencies does yield much improvement in the sound. How low should decay times be is open to debate. Mine is of the order of 200ms but that is too low for some.

Adding absorbent room treatment is certainly a good way (the best I'd suggest) of reducing decay times and so I think to a lesser extent is using DSP/EQ.

Some people fuss about phase but that improves in any case as decay times and FR improves.

Here's some posters measurements including mine in post 60:

https://www.audiosciencereview.com/...in-room-measurements.13540/page-3#post-411614

 

[muslhead]

Unfortunately there is zero chance of adding room treatment or changing much of anything. I have a dedicated audio room that i can do what ever i want. In this area where these speakers are, i am lucky to be able to have speakers so my options to be able to fix the weaknesses found via my measurements will be limited. I was only running the sweeps to get an idea of how bad it was but most importantly if what i heard could be verified with measurements. I know what i heard, now i have to see if my interpretations of the measurements are right ... and why i will need others input for that translation.

 

[Hipper]

Another less complicated way of finding problems, at least in the bass region, is to download these test tones:

https://realtraps.com/test-cd.htm

 

[muslhead]

Another less complicated way of finding problems, at least in the bass region, is to download these test tones:

https://realtraps.com/test-cd.htm

Thanks, as soon as the Buchardt A500 hub can be fixed, i am stuck with a brick and cant test anything.

 

[muslhead]

got it back working and wanted to post one of the REW plots for anyone to comment. What is your take based upon the following:
The noticeable dip between 2-3k are, i believe the speakers built in Fletcher Munson adjustments.
I was expecting more of a downward slope after 100hz and beyond
I dont know how to interpret the bottom end results

Would love to hear what you think especially if it can help educate me on what i am seeing (or not)