PDA

View Full Version : wall question for pros



TnT_Sounds
09-06-2011, 04:31 PM
Wanting to get some advice from the pros and oldschool junkies in the hobby. I'm doing a wall in a 92 Bronco with 8 12's and I have been getting mixed opinions on whats best for audible loudness purposes. I was told a bandpass would be my only option for a wall because of what I'm wanting. And a bandpass has self internal loading walls therefore putting the pressure and audible loudness by the time the wave comes out at my ears in the seats.

If I was to do a regular wall with all subs and port firing forward in any position, will cause the subs and port to load off the front windshield, dash, and firewall and putting all the sound and pressure out the windows and scattered everywhere else but at my ears.

The subs I'm going to be using plot well in a 4th order with .8cu per sub @44hz tuning and 1.4cu sealed per. The response is as flat as anything musical should be from 26-70hz before any +/-3db. Also without taking into any account for cabin gain.

SicAudio
09-06-2011, 04:39 PM
sounds like your on the right track so far

get with John Hone on FB or YT he will confirm or assist you. he is the GOD of 4th order walls.

Team TH (Donny)
09-06-2011, 04:54 PM
What kind of subwoofers are they? Qes on them?

bhsdriller
09-06-2011, 04:57 PM
will 8 12's with port fit facing forward? That might be why people are saying your only option is a 4th order

Moble Enclosurs
09-06-2011, 05:26 PM
Wanting to get some advice from the pros and oldschool junkies in the hobby. I'm doing a wall in a 92 Bronco with 8 12's and I have been getting mixed opinions on whats best for audible loudness purposes. I was told a bandpass would be my only option for a wall because of what I'm wanting. And a bandpass has self internal loading walls therefore putting the pressure and audible loudness by the time the wave comes out at my ears in the seats.

If I was to do a regular wall with all subs and port firing forward in any position, will cause the subs and port to load off the front windshield, dash, and firewall and putting all the sound and pressure out the windows and scattered everywhere else but at my ears.

The subs I'm going to be using plot well in a 4th order with .8cu per sub @44hz tuning and 1.4cu sealed per. The response is as flat as anything musical should be from 26-70hz before any +/-3db. Also without taking into any account for cabin gain.

Due to the amount of pressure that will be caused in such a small acoustical environment, with 8 12s, unless you are concerned with actual spl numbers, will be sufficient in any design properly made. But the ratio of the cabin area with the subs acoustical chamber has to be calculated together for an overall response of the design. This is actually true with any design. If you consider a ported design, it is actually going to act like a bandpass anyhow, but since the environment is so acoustically small compared to the power and compression it will be given, a smooth response will be likely in any position of the vehicle in this case. Yes, vehicle resonances will exist, but with that much reverberation and reflection from the vehicles properties in relation to the subs acoustical chamber properties, it will sound likely no different than actually sticking your head inside an enclosure, which you will notice if this is done, that the response curve does become flat...audibly anyhow.

So, not so much emphasis on phase direction and loading of a specific position should be considered rather than finding the coupling of the enclosure and the vehicle by calculating it as a quasi design. So, two ways about going with this....I'm not going to tell exactly how, because this is something I have figured myself and gives me the reason to do what I do, but like mentioned, one of those ways is to figure for a quasi 4th, if your using a slot ported design, and calculate the front cabin area(what is left) as a ported acoustical compression chamber for the enclosure design. This should give you a good idea of what it will do. Using a 6th order as a wall can be calculated as an 8th order BP as well. Again, when doing wall design, considering the cabin as a compression area of the design is very important to get the ratio of chambers correct.

Does that help at all? If not, I can do the design for you if you like.

As far as the scattering of sound everywhere but your ears, no, it will scatter like that, but will include any listening position as well, with max power levels. The lower the volume, the more you will begin to notice the resonances though, if you are concerned about musical output as well.
Just some thoughts.

i2ain2thunder
09-06-2011, 05:37 PM
^^this^^ 8 12s in a Bronco? Any type of 4th wall is almost gonna sound the same. I love broncos used to have a bronco deuce those things corner like champs especially with trailers behind them.

TnT_Sounds
09-06-2011, 08:50 PM
sounds like your on the right track so far

get with John Hone on FB or YT he will confirm or assist you. he is the GOD of 4th order walls.

Cool thanks... Where are you at in Colorado?


will 8 12's with port fit facing forward? That might be why people are saying your only option is a 4th order

Yes they will fit i have nearly 70" wide I believe.


Due to the amount of pressure that will be caused in such a small acoustical environment, with 8 12s, unless you are concerned with actual spl numbers, will be sufficient in any design properly made. But the ratio of the cabin area with the subs acoustical chamber has to be calculated together for an overall response of the design. This is actually true with any design. If you consider a ported design, it is actually going to act like a bandpass anyhow, but since the environment is so acoustically small compared to the power and compression it will be given, a smooth response will be likely in any position of the vehicle in this case. Yes, vehicle resonances will exist, but with that much reverberation and reflection from the vehicles properties in relation to the subs acoustical chamber properties, it will sound likely no different than actually sticking your head inside an enclosure, which you will notice if this is done, that the response curve does become flat...audibly anyhow.

So, not so much emphasis on phase direction and loading of a specific position should be considered rather than finding the coupling of the enclosure and the vehicle by calculating it as a quasi design. So, two ways about going with this....I'm not going to tell exactly how, because this is something I have figured myself and gives me the reason to do what I do, but like mentioned, one of those ways is to figure for a quasi 4th, if your using a slot ported design, and calculate the front cabin area(what is left) as a ported acoustical compression chamber for the enclosure design. This should give you a good idea of what it will do. Using a 6th order as a wall can be calculated as an 8th order BP as well. Again, when doing wall design, considering the cabin as a compression area of the design is very important to get the ratio of chambers correct.

Does that help at all? If not, I can do the design for you if you like.

As far as the scattering of sound everywhere but your ears, no, it will scatter like that, but will include any listening position as well, with max power levels. The lower the volume, the more you will begin to notice the resonances though, if you are concerned about musical output as well.
Just some thoughts.

Yes all that is good info, some lost me, but I think I got it. I would love to have you design something but my build funds are way tight and I was lucky enough to get some great deals from db drive for equipment.

SicAudio
09-06-2011, 09:06 PM
im way north in Platteville..ur still down in Pueblo area right? i got a friend on ROE from that way...

TnT_Sounds
09-06-2011, 09:26 PM
yeah somewhere near there. I dont frequent roe anymore

Moble Enclosurs
09-06-2011, 09:30 PM
Cool thanks... Where are you at in Colorado?



Yes they will fit i have nearly 70" wide I believe.



Yes all that is good info, some lost me, but I think I got it. I would love to have you design something but my build funds are way tight and I was lucky enough to get some great deals from db drive for equipment.

No problem. I can still help if possible with some advice when needed, just PM me anytime. I'm always around.

SicAudio
09-06-2011, 09:37 PM
No problem. I can still help if possible with some advice when needed, just PM me anytime. I'm always around.


these are the types of members this site needs..

SicAudio
09-06-2011, 09:37 PM
No problem. I can still help if possible with some advice when needed, just PM me anytime. I'm always around.


these are the types of members this site needs..

Moble Enclosurs
09-06-2011, 09:45 PM
these are the types of members this site needs..

Thank you for the support! :) I am very happy to see that what I do is helpful.

galacticmonkey
09-07-2011, 03:41 PM
I could design you a 4th order if you want. Just send me a PM.

shizzzon
09-07-2011, 03:53 PM
What you have been told or how you are interpreting this "advice" is wrong.

You are saying a 4th order bandpass is good because it will reach your ears but a normal 4th order will scatter everywhere and go out the windows?

You need to do some more research on what you want and how you are going to get there.

When you have a port forward firing in a wall, it's always best to have it, if optimal, on one side of the vehicle.
Preferrably driver side.

Your higher score will usually come from passenger side.

If it's swapped, typical interference from the steering wheel can cause score to go down.
Not all vehicles do that though but most do.

It is typical the pressure will increase when the window\door that is on same side as port is open.

IF pressure decreases when you do this, then you have displaced more volume in the vehicle than what is forward the B pillar.
This is the actual goal when building a wall but not all walls will be able to do this based on goals.

This is also why many vehicles into the 170s and higher need to be sealed to continue gaining pressure.

Team TH (Donny)
09-07-2011, 04:14 PM
What you have been told or how you are interpreting this "advice" is wrong.

You are saying a 4th order bandpass is good because it will reach your ears but a normal 4th order will scatter everywhere and go out the windows?

You need to do some more research on what you want and how you are going to get there.

When you have a port forward firing in a wall, it's always best to have it, if optimal, on one side of the vehicle.
Preferrably driver side.

Your higher score will usually come from passenger side.

If it's swapped, typical interference from the steering wheel can cause score to go down.
Not all vehicles do that though but most do.

It is typical the pressure will increase when the window\door that is on same side as port is open.

IF pressure decreases when you do this, then you have displaced more volume in the vehicle than what is forward the B pillar.
This is the actual goal when building a wall but not all walls will be able to do this based on goals.

This is also why many vehicles into the 170s and higher need to be sealed to continue gaining pressure.

This is correct from my experience in competing.

TnT_Sounds
09-07-2011, 11:14 PM
I believe that it was read wrong. I was comparing a normal 4th order vs a vented all subs and port firing forward.

From speaking with mike singer I got the info I was looking for. Surprisingly no computerized program that he knows of will map/plot a 4th order for the vehicle dependent. Their is a certain ratio to stay within per the subs ebp and with slight port tuning and sealed box size I could obtain the sound I am wanting. He also said when doing a bandpass for musical purposes it is key the port remains unobstructed by seats and center consoles as the cabin is going to need to act as another enclosure. So the port is ideally to be located in the center.

I think I got the info I was after though so this thread proved helpful.

Thanks for everyone's insight.

Moble Enclosurs
09-07-2011, 11:31 PM
I believe that it was read wrong. I was comparing a normal 4th order vs a vented all subs and port firing forward.

From speaking with mike singer I got the info I was looking for. Surprisingly no computerized program that he knows of will map/plot a 4th order for the vehicle dependent. Their is a certain ratio to stay within per the subs ebp and with slight port tuning and sealed box size I could obtain the sound I am wanting. He also said when doing a bandpass for musical purposes it is key the port remains unobstructed by seats and center consoles asthe cabin is going to need to act as another enclosure. ...So the port is ideally to be located in the center.

I think I got the info I was after though so this thread proved helpful.

Thanks for everyone's insight.

First bold:Correct, but it can be done. I consider it in my designs.
Second bold:this was mentioned in post number 5, so it is good that he reminded this importance.
Third bold: makes a difference. Most of the high LF dips in the vehicle response will be near the center of the vehicle for the listening position. When loading near the center, it changes the response to accomidate this effect. Great for output.

Just wanted to add these things real quick.

Team TH (Donny)
09-08-2011, 01:57 AM
Ok, 4th order is much better in many aspects.. HOWEVER, you must built it in respect to your desires. You must also have a great understanding about how to design a 4th order not just knowing the "basics" before you seek to build it. A ported enclosure would be easier to design than the 4th order, but the 4th order is much easier to design than say a 6th or especially an 8th order.

TnT_Sounds
09-08-2011, 11:27 PM
First bold:Correct, but it can be done. I consider it in my designs.
Second bold:this was mentioned in post number 5, so it is good that he reminded this importance.
Third bold: makes a difference. Most of the high LF dips in the vehicle response will be near the center of the vehicle for the listening position. When loading near the center, it changes the response to accomidate this effect. Great for output.

Just wanted to add these things real quick.

Great info thank you again man! i'm still trying to learn more as I go before I start on this.


Ok, 4th order is much better in many aspects.. HOWEVER, you must built it in respect to your desires. You must also have a great understanding about how to design a 4th order not just knowing the "basics" before you seek to build it. A ported enclosure would be easier to design than the 4th order, but the 4th order is much easier to design than say a 6th or especially an 8th order.

I was told winisd can plot 4th orders within 2db accuracy and response curves with accurate TSP's. I have klippel accurate specs for my subs and winisd is showing a very "musical" range from 26hz - 62hz before any -3db when I plot them. I am no way claiming to know nearly enough however to be confident enough to build this. I am still second guessing my self. I have got the ratio bit almost down and am still playing with box dimensions that my subs will allow before any thermal or power loss.

hispls
09-08-2011, 11:37 PM
My .02$ build a few 4th orders for a single sub and play with them a bit. Once you have a good feel for what works (ratios and tuning) scale it up X8. What you're talking about is VERY permanent and it would **** to get it wrong.

TnT_Sounds
09-08-2011, 11:42 PM
My .02$ build a few 4th orders for a single sub and play with them a bit. Once you have a good feel for what works (ratios and tuning) scale it up X8. What you're talking about is VERY permanent and it would **** to get it wrong.

Very good idea! That is exactly what I'm afraid of... I'm famous for doing things wrong.

TnT_Sounds
09-08-2011, 11:58 PM
another thing, when I start tweaking with one, if I am wanting more output how would I go about doing so? start with shrinking a side or change tuning etc... and what are the repercussions of doing the changes?

Team TH (Donny)
09-09-2011, 01:18 AM
I was told winisd can plot 4th orders within 2db accuracy and response curves with accurate TSP's. I have klippel accurate specs for my subs and winisd is showing a very "musical" range from 26hz - 62hz before any -3db when I plot them. I am no way claiming to know nearly enough however to be confident enough to build this. I am still second guessing my self. I have got the ratio bit almost down and am still playing with box dimensions that my subs will allow before any thermal or power loss.

Take what info you have now and do as hispls talked about. Build a 4th for a single first. You can test and tweet stuff with a single much easier than thinking you have everything all good to go for all 8, because most likely you wont get it the best on first try.

TnT_Sounds
09-10-2011, 01:02 AM
another random question.. I have heard some talk from bandpass builders and they are saying something about a loading wall..

I thought bandpasses had internal loading walls?

The ratio thing is kind of confusing me now. I really dont know to much about the figures. How does one depict what side of the ratio is to be used for the box? For example a 2:1 ratio; which side is sealed and which is vented? I was told to stay within .8-1.2 for each sub in a common chamber.

Then how do i figure the ratios? Say a 1.5:1 ratio?