[NFG660cc]

I am trying to create a graph for HZ/DB and I am wondering how I am able to get the HZ numbers from the test tones on my reciever? I have a pioneer elite txh 23 and I have run the MCACC setup.


I wanted to check out my room response and I am assuming I will need to get a CD with the different frequencies?


Is there anything I can download?


Thanks guys, appreciate the help

 

[Gertjan]

You typically use something to generate a known tone. Either use a CD with tracks playing tones at different frequencies, or use a PC to play the tones. On the PC you can either play sound files, or use software like Room Equalization Wizard (free). If you can hook up your PC to your receiver, i would highly recommend going the REW way.


Hope that helps

 

[rhcorolla]

This will get you 10 Hz- 300 Hz ...

http://www.realtraps.com/test-cd.htm

 

[NFG660cc]

So far so good. Now another question is if I want to maximize my sub placement (MFW-15) should I be looking and the points on the graph looking for a smooth slope or moving the sub around to see what gives me the biggest db rating at the same output?

 

[glaufman]

Smooth curve.

 

[NFG660cc]

So everytime I move the sub just do all the test tones over again? Is this just a bunch of trial and error?

 

[Gertjan]

All over again

With a piece of software like REW (not trying to push that particular software, i just happen to be familiar with it, but there are other apps like it) it's actually not a big deal: It generates a "sweep" through the freq range and plots the response on the screen for you. Just a simple click and look at the graph, and you can compare graphs from different measurements to see the differences in freq response from placing your sub elsewhere. Make sense?

 

[glaufman]

With many of these apps you also can emit pink noise and view a response in real time as you move a mic (or SPL meter) around the room, or adjust phase, etc...

 

[NFG660cc]



Quote:
Originally Posted by Gertjan /forum/post/18206082


All over again

With a piece of software like REW (not trying to push that particular software, i just happen to be familiar with it, but there are other apps like it) it's actually not a big deal: It generates a "sweep" through the freq range and plots the response on the screen for you. Just a simple click and look at the graph, and you can compare graphs from different measurements to see the differences in freq response from placing your sub elsewhere. Make sense?

Is that the computer software you were telling me about? Do you hook up a mic to the computer? I have the radio shack SPL meter so how would you appraoch this situation? I think I should be good after these questions

 

[Gertjan]



Quote:
Originally Posted by NFG660cc /forum/post/18209159


Is that the computer software you were telling me about? Do you hook up a mic to the computer? I have the radio shack SPL meter so how would you appraoch this situation? I think I should be good after these questions

Room Equalization Wizard, AKA "REW", is the software i was talking about. You can find it here . You install it on your computer (laptop, desktop).


Hook up the computer's soundcard output to one of your receiver's inputs so that REW can play sounds through your speakers. Then you hook up your SPL meter to your soundcard's input, so that REW can record the SPL readings. (Your SPL meter is a basically microphone, and should have an output connector of some sort. My Radioshack one has an RCA jack, i assume yours does as well.)


From there on out it's just a matter of following REW's instructions. You'll have to calibrate the 3 systems (receiver volume, SPL reading and software) through a number of steps, but REW guides you through the steps with good explanation. After that, you're set!

 

[tvrgeek]

But any mic or SPL meter you may have unless it is calibrated is totally unknown below 30Hz.


Pink noise is best used at higher frequencies. Pure tones are more informative in the very low frequencies.


Yes, trial and error. Move the sub, measure all over, move it again. There is no magic to this. More complicated with two or more subs. Of course, if you invest in some bass traps you will find the tuning far easier as you won't have such large nulls.

 

[glaufman]



Quote:
Originally Posted by tvrgeek /forum/post/18212470


But any mic or SPL meter you may have unless it is calibrated is totally unknown below 30Hz.

The site where REW can be gotten has generic cal files for some popular SPL meters and mics that are pretty good for the home enthusiast.