Low Frequency Measurement using Test CD and SPL Meter

[aashish351]

Experimenting with Speaker and seating position has been done by me a lot of times already. And I have on that basis reached a setup which I think offers the best balance between high, low and mid frequencies. Moving speakres closer to the corners does increase the bass, but it does not improve it! And additionally it takes away a slight midrange & treble openness. Like I said earlier, Midrange clarity is most important for me followed by treble and midbass detail. The last is low bass and very high frequencies. Having done positioning, now further improvement can only come from room treatment.

 

[aashish351]

Attached is my room's layout (that's the best i could do with Paint!). I thought it might add more value to this discussion. It is not to scale but I have tried to maintain proportions as much as possible. The room is a dedicated HT / Hi-Fi room, but half of it is also used as my study / office.

By aashish351 at 2012-08-07

 

[sidvee]

Experimenting with Speaker and seating position has been done by me a lot of times already. And I have on that basis reached a setup which I think offers the best balance between high, low and mid frequencies. Having done positioning, now further improvement can only come from room treatment.

Yes next steps for you would be to consider room treatment. Lot of advanced acoustics experts here on the forum. Am sure they will be able to guide you.
Cheers,
Sid

 

[Shivam]

I suggest starting with your room dimensions first.
Calculate the room modes and identify the problematic modes. Keep your speakers so that they don't reinforce these standing waves or cancel out the needed ones at your listening position. Don't just blindly shift speakers and listening position.
Once this is done, place diffusers at the points of first reflections. These can be found out by placing a mirror on the various surfaces and noticing the speakers' images from the listening position.
Next step is to tame any boominess in bass that might remain by using bass traps.

 

[aashish351]

Shivam: is there a particular calculation for finding room nodes?

Sent from my Nexus S using Tapatalk 2

 

[Shivam]

Shivam: is there a particular calculation for finding room nodes?

Sent from my Nexus S using Tapatalk 2

For room Modes-
http://www.bobgolds.com/Mode/RoomModes.htm

 

[aashish351]

ok... I entered the dimensions in that calculator and it is quite a report card (link) which I am afraid I will take a long time to understand. If you can make something out of this please do enlighten...

http://www.bobgolds.com/Mode/RoomModes.htm

 

[aashish351]

Sorry... doesn't work like that.

Could you enter Lenght - 25 ft, Width - 14.5ft, height - 10 ft and look at the results.

 

[Shivam]

Sorry... doesn't work like that.

Could you enter Lenght - 25 ft, Width - 14.5ft, height - 10 ft and look at the results.

Enter the values and then see the frequencies that fall very close to each other or are repeated many times. I took a quick look and found 45Hz, 72Hz, 90Hz etc.. These are being reinforced by the standing waves.

You should put your speakers and your listening position in a place so that the distances to the flat surfaces doesn't translate to these frequencies. You can find that by dividing half the speed of sound by the distances.

Give more importance to frequencies in the lower end and also the primary and secondary modes. Spend some time with the results that you get on that link and you'll start seeing light !!!

 

[Hari Iyer]

that's great hari... i am using a usb dac. please send me the excel file and i will do the EQ and measure the response again and put up the graph.

I have mailed you the excel tool for your room EQ after your analysis of the spectrum. This will help you to not only apply the EQ easily and effectively but also save you valuable time in the process. Do let me know in case you face any issues while using this mini-tool for my correction. You will need to down-load 18 band foobar player for using this tool.

Cheers,