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View Full Version : Birch vs. MDF test (spl results inside)



PSturmer
11-28-2007, 10:29 PM
two identical box's were made. one out of mdf, and the other birch. the specs on them are 1.25 cubic feet net with .75
'' wood thickness. each had a 12'' type R. both box's were sanded in the interior walls with the same grit sand paper. both speakers were brand new. voltage was held constant on battery.

mdf:
1100 watts: 139.8
2800 watts: 143.7

birch
1100 watts: 139.8
2800 watts: 143.7

both had the same output. this may change when larger box's are used, but when small box's are used one does not have the benefit over the other in terms of spl.

here is the birch box

http://i24.photobucket.com/albums/c8/psturmer/birchboxtester.jpg


and here is the equipment. i am still in the process of making the bus bars for the my car so thats why the amps are not in there.

http://i24.photobucket.com/albums/c8/psturmer/test4.jpg

audiobahnuser18
11-28-2007, 10:30 PM
Very nice Test man and good results:D.

MTXman
11-28-2007, 10:31 PM
2800 watts on a type R? crazy.


This test confirmed my suspicions, though - thanks. Didn't think there was any SPL benefit between birch and MDF, and I was correct.

Flipx99
11-28-2007, 10:32 PM
Interesting results.

Although I never considered one over the other for SPL reasons.

Thanks for spending the time though.

JimJ
11-28-2007, 10:32 PM
SPL isn't everything ;)

R/T Pimp
11-28-2007, 10:39 PM
Very nice thank you for taking the time to do something like this. I have been curios on this subject.

Calikid
11-28-2007, 10:42 PM
what amp did you use??

shortyg83
11-28-2007, 10:43 PM
ok and how is the type R after 1800 watts more then it was rated for?

tsenfw
11-28-2007, 10:46 PM
To the naked ear, did you hear any difference in sound quality?

alex3kicker
11-28-2007, 10:48 PM
I need a box for my type R. PM me if the boxes are for sale please.

DejaWiz
11-28-2007, 10:48 PM
ok and how is the type R after 1800 watts more then it was rated for?

Probably a bit like this (http://granitegrok.com/pix/mushroom_cloud.jpg) maybe?

Lakota
11-28-2007, 10:51 PM
I bet you feel like you wasted time lol.

skylineTT
11-28-2007, 10:52 PM
Probably a bit like this (http://granitegrok.com/pix/mushroom_cloud.jpg) maybe?

hahahah:laugh:

PSturmer
11-28-2007, 11:10 PM
what amp did you use??

2 hifonics bxi2607d's. clamped the amps tonight


ok and how is the type R after 1800 watts more then it was rated for?

handles it fine...for burps atleast


To the naked ear, did you hear any difference in sound quality?

only burped it so i am not sure


I bet you feel like you wasted time lol.

not wasted time, i get to save about 200 bucks now. and anyways, i like to work with mdf more.

MTXman
11-28-2007, 11:12 PM
What tone was this? Or was it music?

Jared530
11-28-2007, 11:15 PM
i think the only advantage in using birch is saving gas

Lakota
11-29-2007, 12:15 AM
i think the only advantage in using birch is saving gas

and it's **** when stained.

Skip01
11-29-2007, 12:20 AM
Yehhhh...as we asssumed....weight only thing thats diff

Now get to the resin test, id like to know that....and do angles and stuff.....i know you want to do it...good luck hit me up online when ya do

PSturmer
11-29-2007, 12:23 AM
angled stuff i did already. this week i will make a couple more box's to test fiberglass resin. another thing i will post when i get them is results on sanding ports. of course this will be different for ever box but i am going to find out what kind of increase in db's it can get.

one thing i have noticed. i am like 4-5db's quieter in 18 degrees than like 70. and its only going to get colder.

Lakota
11-29-2007, 12:24 AM
Yehhhh...as we asssumed....weight only thing thats diff

Now get to the resin test, id like to know that....and do angles and stuff.....i know you want to do it...good luck hit me up online when ya do

Resin will probably not make much of a difference.

Lakota
11-29-2007, 12:27 AM
one thing i have noticed. i am like 4-5db's quieter in 18 degrees than like 70. and its only going to get colder.

I've found that my truck likes to be somewhat cool. My scores have been around a db louder on 60 degree days compared to something in the 90+ range. You're crazy for testing when it's 18 degrees lol. Find a building and some heat.

Chevyaudio
11-29-2007, 12:34 AM
thats odd...most people are louder when its cold. cold air=denser

PSturmer
11-29-2007, 12:36 AM
thats odd...most people are louder when its cold. cold air=denser

not where i am. its so **** dry here.

PSturmer
11-29-2007, 12:38 AM
I've found that my truck likes to be somewhat cool. My scores have been around a db louder on 60 degree days compared to something in the 90+ range. You're crazy for testing when it's 18 degrees lol. Find a building and some heat.

i heard resin is .5 but i gotta find out for myself. everything people have said i am kinda checking. it was 18 tonight in my garage and its only going to get colder. i have a lot more testing to do before i am ready for spring break nationals, so i have to keep being cold.

Lakota
11-29-2007, 12:48 AM
i heard resin is .5 but i gotta find out for myself. everything people have said i am kinda checking. it was 18 tonight in my garage and its only going to get colder. i have a lot more testing to do before i am ready for spring break nationals, so i have to keep being cold.

Try single vs. double baffle:)

revrider1
11-29-2007, 12:49 AM
I always wondered if there was a differance, now I know...THANKS

PSturmer
11-29-2007, 12:50 AM
Try single vs. double baffle:)

did it already ....baffle is very very important :)

IgnoreMe
11-29-2007, 04:09 AM
did it already ....baffle is very very important :)

you should try single baffle with dowel bracing VS double baffle with no bracing (ie, is it a better idea to double baffle, or just use a single baffle with dowel braces. i have heard people claim single baffle with dowels is more effective than just using a straight double baffle.)

thats, if you didnt brace in the last test lol

skisloski
11-29-2007, 04:29 AM
random question to the op

what car is that in your avy??

IgnoreMe
11-29-2007, 04:40 AM
96 impala ss...

SPL140.2
11-29-2007, 04:48 AM
Resin will probably not make much of a difference.

resin made the impendance rise when I did my tests. Birch was louder in my tests as well but I was using more power than what the OP was using

egg

audioarsonal
11-29-2007, 10:49 AM
Nice can't wait to hear about the sanded port.

Gary S
11-29-2007, 11:00 AM
I'm not surprised by this test... in theory, people like to use MDF because it should be quieter... but in reality, it's not audible.

I'd like to see a test of a box braced vs. unbraced, and/or different thicknesses of wood.

As long as the box does not balloon while playing, you won't loose SPL. Braces or dowels are a good idea.

PSturmer
11-29-2007, 11:17 AM
you should try single baffle with dowel bracing VS double baffle with no bracing (ie, is it a better idea to double baffle, or just use a single baffle with dowel braces. i have heard people claim single baffle with dowels is more effective than just using a straight double baffle.)

thats, if you didnt brace in the last test lol

well my box is going to be so small there will be no room for bracing. but some physics says this. if you have a side L with thickness R it will flex less if you half the distance of L, so .5L and R, versus if you double R, so L and 2R. meaning it is better to brace with a threaded rod than to double layer the wood. how much stronger the rod will be than double layering will change with every box, but on paper it is very significant.

PSturmer
11-29-2007, 11:20 AM
resin made the impendance rise when I did my tests. Birch was louder in my tests as well but I was using more power than what the OP was using

egg

well if it makes the independence rise then it should be quieter. when i do this test i will clamp the amps. as box's get larger and larger i could see how birch will be louder.


i am going to start resining a box today so maybe friday i will get it on the meter.

Lakota
11-29-2007, 11:57 AM
What about testing wire through the port vs. wire through the box?:laugh:

PSturmer
11-29-2007, 12:02 PM
What about testing wire through the port vs. wire through the box?:laugh:

lol, sadly i did that test:crazy:

audioarsonal
11-29-2007, 12:08 PM
What were the results from the 45 degree corners?

Lakota
11-29-2007, 03:25 PM
What were the results from the 45 degree corners?

Corners are a hit or miss deal. Sometimes they help and sometimes they hurt.

PSturmer
11-29-2007, 04:43 PM
What were the results from the 45 degree corners?

its kinda box to box. sometimes they will help sometimes they wont. the port has my air flow and the box has more air pressure. so in ports, i would always recommend putting corners in or even doing this:

http://i24.photobucket.com/albums/c8/psturmer/100_0871.jpg

but it takes some math to get the correct distances for the corner pieces so the width of the port never changes.

mdillon
12-01-2007, 12:52 AM
is there anyway to test the SQ of these two materials?

percussion companies are very picky with wood. their stance is some resinate more than others. the most used are hickory, birch, and maple.

bonesninja
12-01-2007, 01:04 AM
ok and how is the type R after 1800 watts more then it was rated for?

try 2300 watts more...type r's are 500 watts rms

Lakota
12-01-2007, 12:38 PM
We need more threads like these instead of "will my type r's be louder than my buddy's audiobahn flames?"

IgnoreMe
12-01-2007, 01:07 PM
We need more threads like these instead of "will my type r's be louder than my buddy's audiobahn flames?"

true, but im also sure that there would be more threads like this if everyone had access to a TL.

PSturmer
12-01-2007, 02:09 PM
is there anyway to test the SQ of these two materials?

percussion companies are very picky with wood. their stance is some resinate more than others. the most used are hickory, birch, and maple.

sq is still by ear. i guess i could test the freq responce of each would. but i only trying to get my car loud

PSturmer
12-01-2007, 02:10 PM
i am putting resin in a box right now. so once i get 3 coats in there i will hook it up and get another thread going with the results.

Rawr-DQ
12-01-2007, 03:43 PM
The only thing I am wondering about resin is if the displacement of the airspace after applying the resin is going to make more difference than the resin on the walls itself.

if you end up layering the walls with resin (instead of the mdf soaking it up) you should try and displace some airspace in the non-resin box with a solid object like a piece of mdf.

PSturmer
12-01-2007, 04:29 PM
The only thing I am wondering about resin is if the displacement of the airspace after applying the resin is going to make more difference than the resin on the walls itself.

if you end up layering the walls with resin (instead of the mdf soaking it up) you should try and displace some airspace in the non-resin box with a solid object like a piece of mdf.

yeah i see your point. it is something that should be taken into consideration. when i tested box volumes for this particle speaker. changing the volume from 1.25 to 1.2 will not even yield .1 on the meter. and the tuning changing is also not important in this situation. for the type of box i am working with i need to dramatically lower my tuning from 44 to like 36 to see a .1 drop.

Rawr-DQ
12-01-2007, 05:09 PM
Cant wait to see some results ;)

Maybe you could do a polyfill test at the same time too :)

Lakota
12-02-2007, 02:54 AM
for the type of box i am working with i need to dramatically lower my tuning from 44 to like 36 to see a .1 drop.

That must be nice. A few inches on my port can change my score by a db!

PSturmer
12-02-2007, 02:56 AM
That must be nice. A few inches on my port can change my score by a db!

it usually does. its just when type r's are in such little box's tuning becomes less important.

528hz
12-03-2007, 07:59 PM
I don't know if you answered this (I didn't see it posted) but weight wise, what is the difference

between the 2?