Har-Bal Users Forum BBS

I have been calabrating my monitors and sub and made a test of the acoustics of my room. I used a Behringer EMC 8000 mic and Pinknoise for the test. My problem is how to interpret the test result in Har-Bal should I read both average and peak or only one of them. If I may, what does my test(see screen shot) tell you about my room acoustic.Good or bad
Jan Petter
PS sorry about the size of picture

Hi Jan,

If your using pink noise then just pay attention to the average spectrum trace. I can't see or find your picture? Can you re-post it or send it in an email?

Where and how have you positioned your measurement mic? I'd suggest placing in a position that, as closely as possible, mimmicks the position of your ear(s). I'd do two tests, one for left and one for right and in each case only have the left or right speakers going. That should mean that any dipping/peaking in the spectrum is not due to interference between left and right channels. I'd also suggest doing an impulsive test with a balloon as in this article ( http://har-bal.com/ipw-web/bulletin/bb/ ... .php?t=244 ) as this may highlight room resonance issues more strongly. It also tells you the reverberation time which is important to know as your room may be too wet or too dry.

Regards,


Paavo.

HarBal wrote:Hi Jan,

If your using pink noise then just pay attention to the average spectrum trace. I can't see or find your picture? Can you re-post it or send it in an email?

Where and how have you positioned your measurement mic? I'd suggest placing in a position that, as closely as possible, mimmicks the position of your ear(s). I'd do two tests, one for left and one for right and in each case only have the left or right speakers going. That should mean that any dipping/peaking in the spectrum is not due to interference between left and right channels. I'd also suggest doing an impulsive test with a balloon as in this article ( http://har-bal.com/ipw-web/bulletin/bb/ ... .php?t=244 ) as this may highlight room resonance issues more strongly. It also tells you the reverberation time which is important to know as your room may be too wet or too dry.

Regards,


Paavo.

Hi Paavo,when I said picture I meant the screen shot of Har-Bal that shows the result of my test. I can see the screen shot in my post, however to be sure You will see it I sendt You an e-mail with the screen shot. I just want to know what the screen shot tells
You or other about my room acoustics.
About the mic placement for the test: I placed the mic in my listening position at ears hight. I will do the other tests you mentioned, just need to buy some ballons first
All the best
Jan Petter

To be able to see the image Jan posted, try the following...

Copy the link below, paste it into your browser address bar and hit the 'go' button.
(Don't click on the link, it won't work)

www.angelfire.com/vt2/jps/alexadam/accoustic_test.JPG

The room response screengrab should come up. (If that doesnt work try hitting the reload button while holding down your shift key - that will force your browser to not reload the angelfire logo image from cache)

I'm curious about doing this test on my room too, so am keen to keep the discussion on the list so I can follow it

Looks like things get a bit bumpy below 500 hz to me, but what is acceptable in terms of deviation from the pink noise response?

Thom

Can you describe your room (i.e., dimensions, shape, acoustical treatments, etc.)

Unless you have a very large room you should expect things to look bumpy at the low frequency end. These bumps and dips are caused by room modes (standing waves) and are a feature of real listening environments. Provided they're all about the same amplitude (the peaks) and aren't way above the rest of the response then they should present a problem. I'd say the only one that looks somewhat concerning is the peak around 45Hz which is a bit larger than the others. The remainder are fine and to be expected.

I'd be more concerned with the top end which looks a bit bright by 2-3 dB. But I'm don't know the details so can't really comment further. That is, I don't know the room size the relative location of the speakers and listening position in the room and the reverberation time. At a guess I'd say it looks very much like a near field monitoring situation in a pretty heavily damped room or a large room and the rising top end may be a feature of the loudspeaker itself. For far field monitoring the response is usually much more bumpy than that.

Cheers,


Paavo.

PS - By the way, I still can't get firefox to show that image. I just get a hosted by logo. However, Jan emailed me the image so I know what it looks like.

HarBal wrote:
Cheers,


Paavo.

PS - By the way, I still can't get firefox to show that image. I just get a hosted by logo. However, Jan emailed me the image so I know what it looks like.

I get the same thing

Earle

First of all, thanks for chiming in:) This a valueable lesson for me.My next step was the
reverberation test. I followed Paavos instructions and here are the result:

Reverberation time: 251 ms

The spectral balance of the decay shown in Har-Bal.Click the link for screen shot.

http://www.angelfire.com/vt2/jps/alexad ... t251ms.JPG

I will get back later with my room specifics and treatments.

All the best
Jan Petter
PS.Paavo I sent you an e-mail with the screen shot

Hi Jan,

That looks relatively good though you've got a little stridency in the mids around 1.6kHz. How do you feel about the way your room sounds? Does it please you or trouble you? What sort of treatment does your room currently have? How big is your room? If it isn't very big then I'd say your level of ambience / reverb time is about correct. I'm just wondering if that 1.6kHz area is a trouble to you, otherwise it looks pretty good.

Cheers,


Paavo.

Hi guys
Paavo,you asked
"How do you feel about the way your room sounds?"
I feel it sounds good in my listening position.
"Does it please you or trouble you?"
Do you mean it pleases me as in, makes me smile:)It does not trouble me.
"What sort of treatment does your room currently have?"
Check out the picture of my room,(its messy but I love it:) on the following links:

http://www.angelfire.com/vt2/jps/alexad ... e_room.JPG

http://www.angelfire.com/vt2/jps/alexad ... e_room.JPG

http://www.angelfire.com/vt2/jps/alexad ... e_room.JPG

I am about to make this room as my permanent music room for mixing and making home demoes,so around the first month of summer it will shine.)
"How big is your room?"
Its 4,4 meter x 3,2 meter and floor to celling 2,45 meter.

"I'm just wondering if that 1.6kHz area is a trouble to you"
I have not tought of that up till now, it could cause a problem when mixing.

OT:I almost forgot to mention a great article I came over conserning How to CREATE A REFLECTION FREE ZONE http://www.ethanwiner.com/acoustics.html#rfz

Thanks Paavo for answering my questions:) My new motto is:
A HAR-BAL A DAY KEEPS THE DOCTOR AWAY
All the best
Jan Petter

Hi Jan,

If I use IE I can see the images but Mozilla firefox just doesn't open them for some reason. Anyway, looks like you've got a bit a treatment in place.

Something I would recommend though is to spend some time making the room look comfortable to you. I know it sounds strange but the look of a room can have an amazing impact on the way a room psychologically sounds. I'm quite happy with the look of mine but the lighting is opressive so if I listen to music in it at night it always sounds worse than in natural sunny daylight. I guess if you're blind it doesn't matter so much but if you listen to music with your eyes open it has a substantial affect. I guess it comes from the room look affecting your mood.

Cheers,


Paavo.