well im not sure on the exact material it is, but I have 2 foam inserts from HP Video card box, which looks like a mini egg carton.

2 things.

Just wanting to know whether to make the foam hard? or would it be better to have it soft? and how this will effect the sound?
this is going to be placed behind the speaker like Dynaxorb

also, if I was to try and make the foam hard, what substances could I paint or spray onto it to do this?

Simply put, its not going to work.

Why? Firstly, because products like Dynaxorb cant do what they advertise (increase 'bass' by canceling rear waves). Its plain physics.

Secondly, auditory wave interaction is a complex science. Anechoic chambers dont cost millions for the fun of it. You cant just put egg cartons on the walls, and expect a miracle. The size, and the shape, of the deflective poles are directly related to particular target point wavelengths. None of this thought or design went into designing your inserts, which are used to prevent movement inside a package, not auditory interaction.

So even DynaxOrb is a waste of time?

On any driver with frequencies below around 700Hz, yes.

acoustic foam and other 'rear wave absorbers' may or may not work for you.

depending on the frequencies your mid is playing, and careful choice of the type and size of the 'absorber', will determine the effectiveness of any treatment.

what it will do:
1. help to reduce the re-transmission (by absorbtion) of low-harmonic waves back through the cone to your ears (above ~800Hz) which are reflected from the proximity of the door's outer skin.
2. help to disperse rear wave distortion products above ~2kHz by 'scattering' the waves as they intersect the uneven surface/compliance of the absorber.
3. possibly increase the perception of midbass and mid frequencies due to 1. and 2. above.

what it won't do:
4. increase midbass by absorbing the rear wave.
5. make your car go faster
6. fix your other install problems.

I find that an 'absorber' helps with 'cleaning up' the sound from the speakers by action of 1 and 2 above. They speakers seem to play louder and cleaner with the 'absorber' in place. I say 'seem to' because it's apparent, not real loudness, more like just 'nicer'. I use the more expensive acoustic foam from Jaycar.

ok cool

I'm only running a 2 way set-up, with the mids in the doors, I plan to bring them out and possibly angle them if I can later on.

I don't need extra mid bass as they are sufficient at doing that from my last install imho. my doors are well sound deadened and sealed up.

So if i was to use that piece of foam I have obtained, would i be better from people's theory or experiences leaving the foam soft? or hard?

that would depend on if they are audiophile or mad scientist

You do know your door is a *wet* area ?

putting foam in there will be a moisture trap and may lead to rust.

If its closed cell foam rather than open cell it may not matter but be careful
peace
Cyberpunky

NB as your using a 2 way set up, then using a diffusser type set up may bring benefits as the freqs that driver plays will be above 700ish Hz

thanks for the replies

Just going to go with Dynaxorb for now, and see how that pans out.

I've always found that some foam behind the mids seems to make them sound just a little cleaner, not sure why this is the case. don't really care either.

if your just using random foam, you have to put V Cuts in the bottom of the foam so it will drain when wet.

or get treated foam.

ultimatly you don't need it, but i've always found it helped a little bit, the difference was noticeable.

as for the dynaxorb, i highly doubt the piece of 3mm rubber not quite the size of a midbass behind the speaker is going to do anything. Maybe if you buy the Subwoofer box set, and put 4 in each door.. but then you'd have to be a millionare.. Focal Plain Chant is a better option in that case.

Juls

we cant get focal plain chant in nz
cant even get focal amps

Yes you can.. It just depends where you're looking.

Where exactly are you in NZ?

Its not the surface area of exposure, but the size of the actual peaks and valleys.

For proper dispersion of acoustic waves, the peak to valley distance needs to be greater then 1/4 wavelength with a particular angle (forgot the relationship right now, but I assure you its acute). Therefore, for the dispersion device (dynaxorb, focal plain chant, jaycar whateva stuff) to be effective below say, 250Hz, the peak to valley distance needs to be greater then (343/250=1.3/4=0.343) 34 centimetres)

I am fairly confident that your dynxorb isnt 34 centimeters thick, and therefore wont be effective at those frequencies. Thats the basics. To get more complex, you include the angle of intersection, and the material reflection properties too. This is to ensure that the actual wave gets dispersed properly (in an almost random reflective pattern) as opposed to simply 'softening' the reflection.

auckland

how much is it?

I prefer the sound of my kicks with a full 300x300 acoustic tile slipped in behind the speaker. I didn't notice any decreae in midbass, even though the tile takes up a lot of the airspace. I did notice an increase in 'clarity' as mentinoed by the above posters.

I just dont have the space to fit the z6 mid in the kick panel, theres not much leg room as it is

by changing the compliance of the material regularly across the surface (such as plainchant), that will change the way the pressure zones' energy is absorbed/transferred to the surrounding material.

it won't sound worse with it in there. Especially with 2-ways.

Hey,
Im thinking of lining some parts of my trim (mainly parcel shelf) with foam to stop vibration, do you think it will help? It will just be el cheapo crap.

Probably - a bit... Sound deadening might be better with foam on top if there's any small areas that still vibrate. Some of the really cheap foam breaks down in sunlight or heat so be aware of that too.

Yeah not going for a dynamat kind of thing just looking at dampening the areas where the plastic trim and metal contact.