MDF Baffles = less bass????

[tarbyonline]

Hey guys

Finally got round to putting my component woofers onto MDF baffles. Previously I had the plastic celsus adaptors, fully dynamatted. However, much to my suprise (and dismay) bass is now barely existent. Even with the bass boost on my Amp set up full. I had to trim off the bit of the door card that surrounds the speaker and appears to direct the sound as it was stopping the door going back on. Could this be the problem as the sound is no longer being directed (my door card vibrates like crazy at volume)? Or could it be that now the woofer is too solidly mounted and so the backwaves are cancelling out the bass. Any thoughts on this would be very much appreciated.

 

[mirafioriman]

Have you checked the simple things first such as that the speakers are connected correctly and not reversed? Does the problem show up with the door card on and off? If so then it is not a problem with the door card.

 

[volxstu]

Have you removed any of the sound deadening?
Also it sounds like you have a leakage issue so is the seal worse than before you made the baffles?
Try some silicone on the rear of the baffle to make a good seal, but dont put the speaker in for at least 24h as the silicone will need to dry as it reacts with rubber.

 

[kris lee]

Have you checked the simple things first such as that the speakers are connected correctly and not reversed? Does the problem show up with the door card on and off? If so then it is not a problem with the door card.

I'd have money that you now have one mid out of phase as above!

 

[tarbyonline]

I'd have money that you now have one mid out of phase as above!

Phase is fine, I have triple checked it. both sides sound the same as well (no bass). Sound deadening is as it was (though the plastic adaptors have gone completely). I have remade the plastic surround that was on the door card from CD "cake" boxes (which are a lot more solid than the original plastic) and this has helped a little (lots less door card vibration) - I have attached these to the baffles instead of the door card to direct the sound before it hits the card. I have also placed some dynamat on the doorcard around the speaker and the plastic surround.

Had a play round and turned the low pass filter on (80hz) on the amp. Not much audible and what was is distorted (resonance?). Also, the bass control on the amp (50hz) doesnt have much effect but if I boost the bass at 80hz on the headunit this is audible. Does this sound like a leak stu? Baffle is fitted exactly the same way as the plastic one was. I can feel the air movement from the woofer cone but not hear any bass!!!

 

[Adrian Bravo]

Less Bass is caused by over fishing i think

 

[tarbyonline]

I been thinking. The sound now seems more detailed (if not so bassy). So is it possible with listening being a subjective thing that what I thought was bass wasn't. In that maybe the door has been resonating so much it has maybe tricked my ears? Also, with the baffles being straighter shaped than the original adaptors which are shaped like a cone cut in half there is less air immediately around the speaker. Could this be a factor?

I can see an underseat sub being installed (in about 10 years when i raise the funds!!!)

 

[volxstu]

Normally resonance gives the impression of less bass so perhaps you aught to try and make the seal better and put some foam on anything that vibrates.
Just out of interest is is louder with the door card off?
Also one thing to consider. Is the speaker held in tightly with the screws as MDF can be awful to get a grip on. If i have enough clearance i tend to use threaded inserts.

 

[kris lee]

Something sounds wrong to me, have you tried moving the balance from L+R to full L and full R? Does the bass increase at full L and full R? You may have them in electrical phase but out of acoustic phase therefore creating bass cancelation.

 

[tarbyonline]

Sounds like Stu had the right idea. Got into the car this morning to go to work and to my shock (and delight) there was bass! Im thinking perhaps the wood glue wasnt dry properly last night so creating an air gap? Not sure if it goes as low as it did as there is definitely more detail but its definitely there aplenty. I think volume might be down a bit with doorcard on btw stu, probably because the speakers are behind the original grille (trying to keep car as stock looking as poss). Baffle is screwed in solid to the door card but im going to try and improve the seal as there is a bit of the (very thin) insulation that came with the doors missing on the drivers side which might be causing an issue. Still not got any cash for deadening so going to see if i can find some silicone in the house. If not would neoprene (from a cheap mousemat) have the same effect when squeezed tight by the baffle being attached to the door?

 

[tarbyonline]

Something sounds wrong to me, have you tried moving the balance from L+R to full L and full R? Does the bass increase at full L and full R? You may have them in electrical phase but out of acoustic phase therefore creating bass cancelation.

Kris i will check this tomorrow evening after work if i get a chance. If the speakers where to be out of acoustic phase how would i fix it? Kinda hoping things will improve even more by tomorrow if it is an issue caused by the glue (im getting gready for bass now lol)

 

[paulbfd]

If the speakers where to be out of acoustic phase how would i fix it?

Swap the +ve and -ve wires round.

I spent most of Saturday tuning my car and phase played a big role in how it sounds. Now one side and the sub are out of phase.

 

[volxstu]

It sounds like you are getting there. I doubt that any kind neoprene would be to great as it is quite thick and spongy so will be more prone to moving under the kick of the woofer.
Im not sure exactly what it is that they use but does your car have an inner skin with like a black gunge that seals it on.

 

[tarbyonline]

It sounds like you are getting there. I doubt that any kind neoprene would be to great as it is quite thick and spongy so will be more prone to moving under the kick of the woofer.
Im not sure exactly what it is that they use but does your car have an inner skin with like a black gunge that seals it on.

Nope, only thing I have in the doors apart from the metal (obviously) is the thin foam insulation which is held on with what looks like a glue (its yellow-white and bloody strong). Will prob stick some dynamat around the whole speaker or the aformentioned silicone to ensure there is a good seal.

Got to the point now if I get any more bass its causing serious vibration in the doors so I think some decent soundproofing is next on the menu anyways once i get the funds. Mind you i do have approx 9dB gain set on the amp at 50hZ to get the desired amount of bass response

Paul, not to sure if I know what you are talking about? Do you basically mean put one side in phase and one out?

 

[volxstu]

He means switching the Wires round on the speaker.
Sound deadening the door will make a fair bit of difference to the sound. And i cant see why you are getting loads of rattling i usually just use foam inbetween to stop that but Max Matt Pro would be the best option when you can afford it.

Have you tried reducing the slope that you have set and turning the Volume up on the HU. By adding a slope on the amp you will be adding the chance of distortion through the speaker.

 

[tarbyonline]

He means switching the Wires round on the speaker.
Sound deadening the door will make a fair bit of difference to the sound. And i cant see why you are getting loads of rattling i usually just use foam inbetween to stop that but Max Matt Pro would be the best option when you can afford it.

Have you tried reducing the slope that you have set and turning the Volume up on the HU. By adding a slope on the amp you will be adding the chance of distortion through the speaker.

i think the rattling is to do with the fact that the plastic on the earlier pandas seems cheaper and so the dorcards probably arent as well built as they could be.

Tried fidling with the amp and hu settings and cant get any better. I guess I am stuck with what I have (which compared to stock is fantastic) until I get more funds.

 

[tarbyonline]

Ok, bass seems to come and go but i think i know why! HEAT. The sound in my car literally changes with the weather. Im guessing when the panels are warm they flex more with the air movement due to not being as stiff. Looks like im going to be getting some deadening from the group buy soon!!!!!!!

 

[volxstu]

Well i know that is true but im not sure that it would make that much difference in your car.

 

[tarbyonline]

Its the only way I can explain the change of sound. Hot day = poor bass, cold day = good bass. The doors aren't very big but there does seem to be a fair abount of flex in the outer panel if you push it from the outside - more so than on our astra for example. Adding deading cant hurt anyways i suppose. Was thinking of getting an underseat sub but theres not much point if the bass is going to have no direction to it

 

[volxstu]

Deadening will make a difference to the sound, but if heat does make that much difference to the sound then you will annoy paulbfd a bit.
That does give me an idea though. I am going to run liquid cooling through one of my amps, i wonder if i can install a similar cooling system in the door. :chin: