Tuning a Sony SAWM40 (1 Viewer)

[Marc*F]

I currently have a Sony SAWM40 subwoofer and was thinking if I could adjust the port length a little to lower the tuning frequency of the sub....I know it's a fairly cheap sub and all, but would it help give a flatter response and be even less boomy? Was thinking maybe to tune down around the 30hz mark......

 

[Ernest Yee]

There was a mod posted somewhere in these forums about a week ago. I think someone had essentially filled up the interior with an inch of Polyfil. They claimed that it made it less boomy and a better overall sub. You should do a search for it in these forums.

 

[Marc*F]

Yea I've done the mod with the polyfil and found it helped abit Was thinking now of doing something more direct in changing port length...I think I might give it a try tonight and not tune to low and see if it helps at all, I have a feeling I'll loose a fair bit of output at the expense of a lower tuning frequency tho.

 

[Marc*F]

Added about 6.5" in length to the existing port on my Sony SAWM40, in WinISD it should work out at "approximately" 5hz lower tuning frequency to whatever it is normally (whatever that might be? 40hz?) Made my port extention in about 10 minutes using cardboard and lots of tape

It does seem to go abit lower now but at the expense of SPL output, and most noticible even less boomier (if that would be considered not lingering on bass beats now but more hitting them.)

Then again I could be imagining it all, but i think it sounds alot better now then it was originally.

 

[Manuel Delaflor]

Well, you can always measure the output at specific frequencies, to know if your trick works. It would be helpful to other sawm40 users as well.

 

[Marc*F]

I have a test tone CD i made and an SPL meter, don't ask why I didn't do a test before my port mod I could do some tests with my modded port and if any other Sony SAWM40 users have a normal SAWM40 and spl meter we could post the results here?

Not sure the best way to go about this....test frequencies 20hz, 25hz, 30hz, 35hz and 40hz using 40hz as reference 75db? .......

 

[Manuel Delaflor]

Maybe a little higher, say 85dB, but yes, thats the way. I would not use the "correction files" for the SPL meter that float in the Net, I do not trust them.

Lets hope other users posts their results.

 

[Kevinkall]

Just a quick question on the polyfill mod, do you fill the ENTIRE bottom of the sub. Or do you add the polyfill around the port?

THANKS!

 

[Marc*F]

Pretty much just fill the inside up not too tight making sure you don't block the port, so most of it would probably not be on the bottom.

Ok, I'll do some testing tonight with reference level 85db at 40hz then down every 5hz to 20hz and post my results soon. Again if anyone eles has a Sony SAWM40 it would be great to compare results.

 

[Kevinkall]

So I should just fill up the sides of the sub(top to bottom) and leave the middle section where the port is empty? I've always been a little confused about this mod.

Where would I get a test tone cd?

THANKS!

 

[Marc*F]

Pretty much, it doesnt need to be packed in any sort of order really....as long as you don't block the flow of the port.

Have a look for a little utility on the net called NCHTone, basically allows you to output certain tone frequencies to wav files that you can burn to cd and use.

 

[Marc*F]

Quick question with measuring the output frequencies of my sub, should this be done at 1 meter?

 

[Marc*F]

Ok got some results, done at 1 metre with reference at 85db for 40hz.

Pretty poor result Hope nothing is wrong or its just how a Sony SAWM40 works...

40hz - 85db
35hz - 76db
30hz - 64db
25hz - why bother

Anyone with a Sony SAWM40 and SPL meter that can compare?

 

[Kevinkall]

I'll give it a go this weekend and post my findings.

Is the polyfill mod the only thing that you've done to your sub?

I've also added some internal braces and I also did the MOD PODGE mod.

We'll see if I get any different results.

 

[Marc*F]

Sounds good

I have done the polyfil mod and extended the port to give an "approximate" 5hz lower box tuning...

 

[Manuel Delaflor]

Marc*F

For your results, seems that you actually did the contrary to what you wanted :frowning: Lets wait for the results from Kevinkall's sub, but I see that it does not have response to 35Hz (9dB down is a lot).

Maybe you should undo the new port?

 

[Kevinkall]

Quick question...

How do you get the tones to just play from just your sub? I downloaded the NCHTone software and made a cd with tones ranging from 40hz down to 20 hz. I just don't know what I need to do to just hear them from my sub. THANKS.

 

[Marc*F]

NCHTone should be outputting the files as *.WAV, just make sure you create an AUDIO CD from the wav files and your dvd/cd player should read them as normal audio tracks.

Anyone gotton any results from their Sony SAWM40 to compare?

 

[PatSloan]

Guys,

Here is what I tested:

25hz - 74db
30hz - 73db
35hz - 78db
40hz - 85db

I think I will try a 20hz

I hope that I have my spl meter set right. I have an rs digitial one. Just got it so I am not sure how to use it correctly. I have it set range to 80, response slow and wieght to C

Is that correct?


These are measured after putting in the stuffing.

--pat

 

[PatSloan]

20hz was 57db. I could not feel or hear it :frowning:

One thing to note for me is that if I played 40hz over 85db my mitsubishi tv would rattle. Should I be worried for normal movie watching would you expect to hit 85db in those ranges?

Thanks.

--pat