If you're really worried just brace the box. Waste of dynamat in my opinion.
Jeffdachef
5,000+ posts
Gunz That Turn on Nunz
complete waste of money, you are better off doubling up on the wood or using 1 inch thickness wood or even getting a properly engineered sound quality oriented ported box or 1/4 wave transmission line box built by someone who knows what they are doing. Guy that recommended lining the inside of the subwoofer box with dynamat for you is a quack job, find a different guy.
You will get infinitely better results using that dynamat on your car vs your sub box. It will do almost absolutely nothing for your sub box.
- Thread Starter
- #4
Thank you. And the other poster too. No, my audio installer guy did NOT recommend lining my subwoofer with Dynamat, that was MY idea, and he kinda nixed it.
We are quickly losing any meaningful conversations about this via MISinterpretations of what I wrote initially and possibly ego driven misunderstanding of speaker enclosure theory as well!! As well as fallacious "appeal to authority" logic mistakes like "...or even getting a properly engineered sound quality oriented ported box or 1/4 wave transmission line box built by someone who knows what they are doing..."! We have no "National Bureau Of Standards" about auto audio! Everyone here seems to think they know more than everyone else much of the time! I'm just trying to have a good and meaningful conversation about this issue!
John Kuthe...
- Thread Starter
- #6
How so? I know quite a bit about physics, Electrical Engineering, etc. Don't just throw around cool terms like you know what you are talking about. Explain it!
John Kuthe...
Perhaps you can explain it to yourself, haha.
Company i was talking to about 3yrs explained to me that Anti-Drumming doesn't absorb the sound and convert it into heat like deadening does but instead literally acts like a wall for sound waves. So when sound hits it, it bounces off of it and keeps it in the cabin or environment it's displacing.
However, in an enclosure, it may cause unwanted resonation.. Something to test. I know it was talked about greatly with ported enclosures but with sealed.. i do not know how it would react.
Company i was talking to about 3yrs explained to me that Anti-Drumming doesn't absorb the sound and convert it into heat like deadening does but instead literally acts like a wall for sound waves. So when sound hits it, it bounces off of it and keeps it in the cabin or environment it's displacing.
However, in an enclosure, it may cause unwanted resonation.. Something to test. I know it was talked about greatly with ported enclosures but with sealed.. i do not know how it would react.
- Thread Starter
- #8
I can follow that. Yes exactly the difference between reflection and absorption. And to my mind a hard wooden surface is gonna reflect more sound pressure waves than it will absorb them, whereas Dynamat is designed to absorb vibrations, sound pressure waves, etc. Hence a damping effect. True? I think so.
PS: I'm not gonna argue with your ego!
John Kuthe...
What's the issue again? Bracing is likely a better alternative to using dynamat on the enclosure if you're worried about suppressing panel vibrations.
A solid background of EE and Physics should have shown you the difficulty in approximating changes made to a complex system and unfortunately unless you build 2 exact boxes line one with dynamat and keep the thousands of environmental variables constant while testing, one can't definitely say the amount of change that you would see. It's likely not going to have a noticeable impact in my not so humble opinion.
A solid background of EE and Physics should have shown you the difficulty in approximating changes made to a complex system and unfortunately unless you build 2 exact boxes line one with dynamat and keep the thousands of environmental variables constant while testing, one can't definitely say the amount of change that you would see. It's likely not going to have a noticeable impact in my not so humble opinion.
- Thread Starter
- #10
Yep, that would be a proper objective scientific way to gather evidence. But of course NONE of us are gonna do that.
As I said originally with the primary objective of a speaker enclosure is to separate the sound pressure waves coming off the speaker cone diaphragm from those coming off the back of the speaker cone which are 180 degrees out of phase with the sound pressure waves off the front and radiating out ONLY the one off the front of the speaker cone and damping/muffling the one coming off the back of the speaker cone. An idealized model I read about years ago was an infinite plane in which the speaker is mounted an the observer being on one (the front) side experiencing only the sound pressure waves off the front of the cone and ALL the 180 degree out of phase sound pressure waves radiated off the back of the speaker cone being lost on the other side of the infinite plane mounding surface. (Thats one hell of a run on sentence, eh? ;-) )
John Kuthe...
So is this a thought experiment in which the two different enclosures are suspended in a medium of uniform composition,density, and temperature? In that case it's likely still too complicated for anyone to make a guesstimate.
A thought experiment for you:
Would any sound waves created due to enclosure vibration maintain a 180 degree phase difference with the sound waves being produced by the front?
Out of curiosity are you trying to find evidence to refute your installer or is it for your own edification? ;-)
A thought experiment for you:
Would any sound waves created due to enclosure vibration maintain a 180 degree phase difference with the sound waves being produced by the front?
Out of curiosity are you trying to find evidence to refute your installer or is it for your own edification? ;-)
- Thread Starter
- #12
I'm looking for the wisdom of experience here. What I primarily see on the website is a lot of ego battling and hearsay evidence. Yeah I think I know what I'm doing, so does everyone. I'm trying to keep it all "just the facts", which ego driven people like males somewhat experienced with auto audio installations seem to have a hard time sticking to, from what I've seen here so far.
John Kuthe...
It's interesting you keep mentioning ego driven responses when you have tried to make it clear in a couple of your posts that you have enough knowledge of speaker enclosure theory, physics, EE, etc to "know" one way or the other. You ask for wisdom of experience, but yet when people with experience or thoughts on the matter chime in (That is what you requested in your first post.) you marginalize their posts as "ego driven." It comes off as extremely ostentatious and self righteous. Jeff as well as shizzon are really helpful to many longstanding members and newcomers here, and it's frustrating to see someone come onto the forum and treat them so dismissively.
If you truly want the facts there are plenty of credible online resources since facts aren't always easily derived from experience. I strongly encourage you to revisit speaker enclosure theory and fundamental physics that you purport to know. The detailed answer your looking for is pretty easily found and doesn't require you to interact with self deluded "experts" of whom you're quick to dismiss.
- Thread Starter
- #14
I'm sorry everyone. Yes I can be a PITA, I'm just trying to glean any wisdom backed up by scientific theory and physics.It's interesting you keep mentioning ego driven responses when you have tried to make it clear in a couple of your posts that you have enough knowledge of speaker enclosure theory, physics, EE, etc to "know" one way or the other. You ask for wisdom of experience, but yet when people with experience or thoughts on the matter chime in (That is what you requested in your first post.) you marginalize their posts as "ego driven." It comes off as extremely ostentatious and self righteous. Jeff as well as shizzon are really helpful to many longstanding members and newcomers here, and it's frustrating to see someone come onto the forum and treat them so dismissively.
If you truly want the facts there are plenty of credible online resources since facts aren't always easily derived from experience. I strongly encourage you to revisit speaker enclosure theory and fundamental physics that you purport to know. The detailed answer your looking for is pretty easily found and doesn't require you to interact with self deluded "experts" of whom you're quick to dismiss.
John Kuthe...
LosIsATool
5,000+ posts
CarAudio.com Veteran
The wisdom is it's a dumb idea and a waste of a already mediocre deadening product. It's not going to do anything. There is no need to add mass to the inside of a box that should already be well braced.
Deadeners main objective is to add mass to lower resonance in metal. Not fiber board
You can have all the degrees in the world. We do this, study this, live this, compete with this.
Deadeners main objective is to add mass to lower resonance in metal. Not fiber board
You can have all the degrees in the world. We do this, study this, live this, compete with this.
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