SPL tricks- In progress from Shizzzons Build

[shizzzon 461]

I'm gonna be trying a lot of things and reporting what does and doesnt work.

Unfortunately, i can't post back everything as the wall and corners have already been made.

What i will be focusing on is head unit settings, amp settings, port area, port length, port angle, car seal jobs, car bracing, car mods, internal box coating, etc...

As of right now, i did discover something rather interesting-

The difference between playing a sine wave vs a square wave on the meter using a TLab.

At low volume, a got a reading of 140.2 using a sine wave.

At the same volume, i got a reading of 142.1 using a square wave.

Now, when ran full tilt and clipped-

SQUARE wave- 147.2

SINE wave - 147.6

So.. if you plan on using a square wave, do not clip it or your score will drop.

Square wave may be useful for those who have TONS of power and are limited on fusing due to competition requirements. Square waves have a higher amplitude so u can get more dbs out of the sound track.

(i serve square waves in my test tones, )

[jcarter1885 995]

good info, I saved this page as one of my favorites so I can have all these useful tips at one click away

[shizzzon 461]

It is a very good idea to build a sealed box or go buy a sealed box with a sub inside of it, i'd prefer a minimum of a 10" sub for your in-car response graphs.

You need a sealed box because a sealed box doesn't naturally peak at any one note so you would want that in your car to find what note your car peaks at.

Vehicles have all kinds of corners, edges, contours, etc... and creates havoc for natural sound. Therefore, at some point in the car, it will have a frequency that will just cause chaos in your ride, this is what you need to find.

So, for those NOT building walls, position your sealed box and face the sub in the direction the PORT would be facing.

Now, you will need a notebook already ready for this test. Right down notes 20-100hz individually because u will be writing down Db numbers next to each one!

Now, turn up volume half way, do NOT rev the engine but leave car on.

Start with 20hz and work your way all the way to 100hz regardless of how quiet it is.

Once you have this, this is your official in-car response graph for your vehicle for the desired box position.

If you do not know which way the port will be facing yet, turn your box around but every time you turn it or flip it, redo the entire test over because the graph will change.

ALSO-

opening opposite door and\or rolling that window down will almost always result in a louder score.

Because of this, you MUST also test 20-100hz with this door and\or window open as the response graph will be VERY different.

The peak note in your car will\should remain the same but other notes will change. This is useful info for building a daily driver port or a port for bassrace.

[Lucky 76 5]

It is a very good idea to build a sealed box or go buy a sealed box with a sub inside of it, i'd prefer a minimum of a 10" sub for your in-car response graphs.

You need a sealed box because a sealed box doesn't naturally peak at any one note so you would want that in your car to find what note your car peaks at.

Vehicles have all kinds of corners, edges, contours, etc... and creates havoc for natural sound. Therefore, at some point in the car, it will have a frequency that will just cause chaos in your ride, this is what you need to find.

So, for those NOT building walls, position your sealed box and face the sub in the direction the PORT would be facing.

Now, you will need a notebook already ready for this test. Right down notes 20-100hz individually because u will be writing down Db numbers next to each one!

Now, turn up volume half way, do NOT rev the engine but leave car on.

Start with 20hz and work your way all the way to 100hz regardless of how quiet it is.

Once you have this, this is your official in-car response graph for your vehicle for the desired box position.

ALSO-

opening opposite door and\or rolling that window down will almost always result in a louder score.

Because of this, you MUST also test 20-100hz with this door and\or window open as the response graph will be VERY different.

The peak note in your car will\should remain the same but other notes will change. This is useful info for building a daily driver port or a port for bassrace.

im taking this peak note is strictly for competition and not for daily correct? ... i would like to know more about ur wall build as i plan on walling 4 18s in my suv ... im subscribed to this topic as well

Edited July 27, 2009 by Lucky 76

[shizzzon 461]

Yes, you would use this method to find your peak for competition use, but because i describe to test all the way to 100 from 20hz, it's also to show you how your vehicle will respond to basically all the notes your subwoofer may interact with for daily driving so it can be used for both.

[shizzzon 461]

It is wise to use as much port area as possible.

How much? well, i cannot say for sure exactly on a given ratio but i can assure on what i've been testing recently, port area plays a LARGE factor on spl output.

Also, if your port is very short on the length side, you will also lose potential spl.

I am currently runnin 144sqin of port area and whenever i try to shrink it down just 8 sqin, my score does drop!

There is a point where you can have too much port area. This is why you will need a meter to find out for sure. A good rule of thumb is never exceed the area of port to the cone area of subs you are using.

Now, for me, i'm running 706 sqin of cone area at only 144 sqin of port. Not my choice, my car is only so big. I always like to think of designs that are almost impractical to do but still feasible...

Without a port in my wall, i have 185.75 sq in. If i can construct a port using thinner material or submerge the port inside the box without taking up port area.. i can gain some port area back!

This is coming from a design that cannot be altered so worse-case scenario. I have a few ideas if i choose to alter the existing port area if i want to reach a higher goal....

More testing to come soon.

[rmzsuzuki89 61]

Useful info, subscribed.

[shizzzon 461]

Some more info-

I did a comparison a while back of using a sine wave vs a square wave as source material for burping in competition.

the result was-

The square wave IS significantly louder than a sine wave as long as the signal is not clipped!

If using a sine wave and you drive it into severe clipping, the sine wave will actually be louder!

Well, i was under the assumption that for comp rules that put you in classes based on fuse rating, using a square wave would be beneficial as long as it's not clipped...

I just got done doing some more testing on that theory and it may NOT be useful.

Doing a very low power output test, i pulled 3.3A of current running a sine wave.

running the same tone but as a square wave at the same volume level, yes it is louder but is also drawing 4.0 amps too.

So, the square wave draws more power but is louder... it is up for grabs as to which would make someone louder on the mic when the signal is not clipped due to fuse limiting.

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Something else i have been noticing when messing around with someone else's design.

If you have a trunk vehicle with setup in the trunk-

If you plan on competing, MAKE SURE you have plenty of breathing room around the box to get into the cabin area!

I was messin around with a build where the subs face forward and are almost flush with the back seat when folded down and ported to driver side. Because the box is so close to the back seat wall, attempting to seal ANY holes in the rear deck resulted in a loss of output!

Why?

Because it is using every little hole possible to reach the cabin area.

IT's best to have a meter when doing this, but if you are planning on ever sealing up the trunk to get the most out of it... make sure the port is firing into the cabin. Do not give yourself "some room" in front of the box and seal everything else... that's bad.

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Competition Port Area recommendations, (my personal opinion)-

Most companies will tell you that they recommend 12-16sqin of port area per cube of internal NET volume. I'm finding that VERY LOW for comp use!

Surprised? u think that was pretty large? Well, actually it isnt...

I strongly suggest the following values-

28-32sqin PER CUBE NET ported.

Examples of recommended installs based on average box requirements from companies most offered here on SSA-

single 10" sub - 32-60sqin

dual 10" subs - 64-120sqin

single 12" sub - 56-85sqin

dual 12" subs - 112-170sqin

single 15" sub - 88-130sqin

dual 15" subs - 176-260sqin

single 18" sub - 130-190sqin

dual 18" subs - 260-380sqin

These recommendations are my personal opinion from testing and should provide best output potential on the mic.

[Lucky 76 5]

Some more info-

I did a comparison a while back of using a sine wave vs a square wave as source material for burping in competition.

the result was-

The square wave IS significantly louder than a sine wave as long as the signal is not clipped!

If using a sine wave and you drive it into severe clipping, the sine wave will actually be louder!

Well, i was under the assumption that for comp rules that put you in classes based on fuse rating, using a square wave would be beneficial as long as it's not clipped...

I just got done doing some more testing on that theory and it may NOT be useful.

Doing a very low power output test, i pulled 3.3A of current running a sine wave.

running the same tone but as a square wave at the same volume level, yes it is louder but is also drawing 4.0 amps too.

So, the square wave draws more power but is louder... it is up for grabs as to which would make someone louder on the mic when the signal is not clipped due to fuse limiting.

---------------------------------------------------------------------------------------------------------------------------------------------------------

Something else i have been noticing when messing around with someone else's design.

If you have a trunk vehicle with setup in the trunk-

If you plan on competing, MAKE SURE you have plenty of breathing room around the box to get into the cabin area!

I was messin around with a build where the subs face forward and are almost flush with the back seat when folded down and ported to driver side. Because the box is so close to the back seat wall, attempting to seal ANY holes in the rear deck resulted in a loss of output!

Why?

Because it is using every little hole possible to reach the cabin area.

IT's best to have a meter when doing this, but if you are planning on ever sealing up the trunk to get the most out of it... make sure the port is firing into the cabin. Do not give yourself "some room" in front of the box and seal everything else... that's bad.

-----------------------------------------------------------------------------------------------------------------------------------------------------------

Competition Port Area recommendations, (my personal opinion)-

Most companies will tell you that they recommend 12-16sqin of port area per cube of internal NET volume. I'm finding that VERY LOW for comp use!

Surprised? u think that was pretty large? Well, actually it isnt...

I strongly suggest the following values-

28-32sqin PER CUBE NET ported.

Examples of recommended installs based on average box requirements from companies most offered here on SSA-

single 10" sub - 32-60sqin

dual 10" subs - 64-120sqin

single 12" sub - 56-85sqin

dual 12" subs - 112-170sqin

single 15" sub - 88-130sqin

dual 15" subs - 176-260sqin

single 18" sub - 130-190sqin

dual 18" subs - 260-380sqin

These recommendations are my personal opinion from testing and should provide best output potential on the mic.

very useful information ... i dont think there will be as much of a difference in current draw once you increase the volume further ... it could be different tho because facts state that there will actually be a greater percentage drawn from the square wave

[rushnrun 14]

to further test your square waves....

why don't you adjust your volume until the amp is consuming the same current with the sine as the square wave? and meter spl at the same time..? I don't have any square tones or I could/would try myself...

[shizzzon 461]

technically, that may only happen once clipping occurs and by then it's too late...

However, i could try, i would just need 2 people to do it so the next time i'm at a meet, i'll try it.

I take that back. I'll just set the ammeter to peak hold and do it myself tomorrow.

[shizzzon 461]

I've been thinkin, i'm not gonna create a new thread about the following post but just keep it here.

The following is a list of some AVERAGE scores to expect when running certain setups installed in vehicles.

I can't list every possible thing but just what i've experienced.

Again, this is MY EXPERIENCE so if you are not up to par with the following list, you have design issues. If you surpass the list with flying colors above and beyond... you know more about competing than the average joe.

So, here is what i've witnessed over several years-

Single 10" sub-

140db+ with 1500w or more

Dual 10" subs-

143db+ with 2000w or more

Single 12" sub-

143.5db+ with 1500w or more

Dual 12" subs-

146db+ with 1500w or more

Single 15" sub-

145.5db+ with 1500w or more

Dual 15" subs-

148db+ with 1500w or more

Single 18" sub-

146.5db+ with 1500w or more

dual 18" subs-

149db+ with 1500w or more

This is ALL tuned in the LOW 30s for typical daily driving!

If you are not up to par with these specs and have the right amount of power or more...

You have design problems or environment restrictions.

Examples are-

Tuning too low for daily, box not large enough, port not large enough, port placement not the best, same goes for subs, air restrictions in cargo area, very high impedance rise(rare), extreme voltage drop, air leaks, box design failure, improper tuning of head unit or amp.

You can achieve lot higher numbers listed above usually by tuning slightly higher to match car's peak note and vehicle and box modifications to accomodate excessive pressure levels. Combine this with suggested port areas above and you could start breaking state records!

[shizzzon 461]

Ok the results-

Square wave-

149.03db pulled 237.6A

Sine Wave-

149.29db pulled 232.2A

This was maximum unclipped signal so the sine wave still won in both pressure and lower power draw.

I'd say square waves are pointless for competition...

[rushnrun 14]

good test

[shizzzon 461]

i believe the possible reason the square wave doesnt win is because a square wave is generated with a higher medium of tones than just a single peaking tone.

I'm curious to see if i go about regenerating some "boosted" sine wave tracks if they could meter higher than normal sine waves.

If it does, these tracks are not legal for world finals but ARE legal during the season.

[Lucky 76 5]

Ok the results-

Square wave-

149.03db pulled 237.6A

Sine Wave-

149.29db pulled 232.2A

This was maximum unclipped signal so the sine wave still won in both pressure and lower power draw.

I'd say square waves are pointless for competition...

upsetting results lol

[Lucky 76 5]

I've been thinkin, i'm not gonna create a new thread about the following post but just keep it here.

The following is a list of some AVERAGE scores to expect when running certain setups installed in vehicles.

I can't list every possible thing but just what i've experienced.

Again, this is MY EXPERIENCE so if you are not up to par with the following list, you have design issues. If you surpass the list with flying colors above and beyond... you know more about competing than the average joe.

So, here is what i've witnessed over several years-

Single 10" sub-

140db+ with 1500w or more

Dual 10" subs-

143db+ with 2000w or more

Single 12" sub-

143.5db+ with 1500w or more

Dual 12" subs-

146db+ with 1500w or more

Single 15" sub-

145.5db+ with 1500w or more

Dual 15" subs-

148db+ with 1500w or more

Single 18" sub-

146.5db+ with 1500w or more

dual 18" subs-

149db+ with 1500w or more

This is ALL tuned in the LOW 30s for typical daily driving!

If you are not up to par with these specs and have the right amount of power or more...

You have design problems or environment restrictions.

Examples are-

Tuning too low for daily, box not large enough, port not large enough, port placement not the best, same goes for subs, air restrictions in cargo area, very high impedance rise(rare), extreme voltage drop, air leaks, box design failure, improper tuning of head unit or amp.

You can achieve lot higher numbers listed above usually by tuning slightly higher to match car's peak note and vehicle and box modifications to accomodate excessive pressure levels. Combine this with suggested port areas above and you could start breaking state records!

what are u expecting me to hit once 4 18s go in w 8000 watts ... u know were making my suv a 2 seater now dont u lol

[shizzzon 461]

well, with proper bracing and all that, it should do around a 55-56 on music and a 57-59 if used for comp...on average.

[Lucky 76 5]

well, with proper bracing and all that, it should do around a 55-56 on music and a 57-59 if used for comp...on average.

=)

[shizzzon 461]

Also don't be surprised that if u really do listen to it at that level for driving and u get used to the pain, that u will soon be a member of a major hearing aid message board.

[shizzzon 461]

wherever there is weatherstripping... there is a leak in pressure.

Any weatherstripping on a vehicle that is in an area where sound pressure will be in effect will need to be filled or blocked off.

Filled is more of a permanent solution, using runs of duct tape PER RUN tends to be the better solution.

This will attempt to keep pressure in the vehicle as long as possible to help your score.

Also, it may be to your advantage to remove ALL interior panels and factory sound barriers and look for any air leaks that could effect your score.

Some parts of a vehicle may leak right outside and you never know it if u don't fully inspect your vehicle!

I do strongly advise this though-

If you have come in here to try to gain higher pressure level for your install and you already knew some of these tricks and your score really isn't up to par, STOP!

These tricks are intended to help you gain after you have properly built a box and tuned it and have it positioned properly for your vehicle.

Without making the source the best it can be, everything else is pointless to try and gain.

[Lucky 76 5]

Nawyce! Dont know if I want to duct tape my aviator though. How is my box prints coming out?

[shizzzon 461]

havent messed with em yet, sometime this weekend i will though...

[SPLScion 3]

wherever there is weatherstripping... there is a leak in pressure.

Any weatherstripping on a vehicle that is in an area where sound pressure will be in effect will need to be filled or blocked off.

Filled is more of a permanent solution, using runs of duct tape PER RUN tends to be the better solution.

This will attempt to keep pressure in the vehicle as long as possible to help your score.

Also, it may be to your advantage to remove ALL interior panels and factory sound barriers and look for any air leaks that could effect your score.

Some parts of a vehicle may leak right outside and you never know it if u don't fully inspect your vehicle!

for example, I finally got some deadening for my TC and when going to install it on the rear 1/4 panels I found this!

[shizzzon 461]

you know i never messed with those!

I had thought about it but when i burped a 148... well, i was in the process of preparing for the wall build right after so i never messed with them.