SPL testing in '07 Scion Tc

[SPLScion 3]

Not owning a meter I have not gotten to do much testing. My SPL comp runs have been as much for testing purposes as for fun. I have done 3 testing sessions not in comps. and the 1st 2 were in between comp runs for 20-30 mins each and then yesterday I finally got a chance to do some rigoris testing for a few hours. Here's what I learned helps my TC get louder:

1. a. Passenger seat all the way forward as if some one was getting in back seat of my 2 door, a funny thought cuz I made my car a 2 seater with a massive enclosure.

b. The back of the seat all the way forward. I have a pic. of this if any1 is having a hard time visualizing, but its a common practice with db-draggers to do this and it makes a huge difference on the mic.

2. Sun visor down, almost verticle. The point of this in conjunction with the seat being forward is to make a condensed and aimed pathway to the meter, and step 1 + 2 adds about 2 db's to my score! thats alot imo!

3. Glove box OPEN this gives me .2 db's every time.

4. Vents on dash closed, this gains me .1 db to .2 db

5. Sunroof shade closed (on both sunroofs) this gains me .2 every time

6. Enclosure kitty cornered with the ports aimed more to drivers side, if you look at my avatar you can get a feel for what that looks like. I gained over a db from this.

7. Port 6.5 inches from back of hatch yeilded the best reluts making a 1 db gain for me from having it further away. I need to lengthen my wires to the box so it can go back further then test, cuz it was as far as they would reach atm, so who knows, 6 " or less might gain me more...

8. My dash score is exactly 1 db higher at the kick over the legal position on the windshield.

The rest of my testing invloved freq. testing song testing (cuz this year my class requires me to play only music) and settings adjustment. Apparently my DMM is junk cuz my amps were not gain matched properly one amp was 3 detent clicks off lol.

Apparently Kenwood HU's are very touchy when it comes to SPL applications. One click too high on volume or subwoofer level throws off my score by a whole db or more! My friend told me he had a Kenwood HU, albeit a different model and had the same prob., so it required a ton of testing to find the sweet spot for all of the settings on the HU.

I tested my box rise, 1 ohm each sub, and clamp tested my amps power and found I was getting rated power but no where near enough which I obv knew already. I am giving my subs only 1300 watts which explains why I am so quiet! My friend with the meter, who also happens to be my box designer/builder and holds a few WR's tells me that I am pretty loud for so few watts. He says that a 145.2 (after a long hot day of testing w/ hot VC's) is respectable, but I am an SPL guy, it will NEVER be loud enough!

I really wish there was a way to make my amp see a true ohm load of 1 ohm, but I suppose I'll just have to get a monster amp and power through my box rise. For the record I know a 1 ohm rise is good and most have much more then this, just frustrating cuz I am in a class this year that limits the amp to 2000w rated, not clamped.

The day before this testing session I put in some deadening on the rear 1/4 panels, while doing this I found some huge azz vents on the panel that vents to the outside. Shizzzon, do you know what I am talking about? I can post a pic if any1 needs. I taped them off then put foam in front of them and taped over that, its a short term fix but I will be thinking about a long term solution non-stop. What did you do about these shizzon? I fig. you may have done nothing cuz your walled off so it would affect you less but worth asking ya :-)

When replacing the little rear tail light access panel I discovered that there was a leak in the metal right above the tail light on passenger side, so I taped that up 4 the short term. Will have to fiberglass or bondo that from inside soon.

I duct taped around my sunroof and it def. helped seal it even though I only used 2 strips of it on each side. Shizzzon what did you do about how hollow the rear 1/4's are (really I mean the "c" pillars. My friend suggested I use expanding foam to pack it tight and seal it up, what do you think about this?

OK, thats all I can remember for now, but I'll say this before ending: Testing is the single most important thing I have done to get loud. It has given me my largest gains, and at one point I went from an 800w amp to 1800w and yet gained less then from a few short testing sessions. When all was said and done testing has gained me over 5 db's! for free, not including my comp runs which I consider testing sessions in their own right.

I guess I'll say one more thing before ending, a huge Thank You to SSA, its mods. who are very informed people on many subjects and SSA members for helping me (even when ya didn't know it) and educating me. A special thanks to shizzzon for all his posts, he always posts insane testing/result posts which help me in particlular having the same car and many of the same goals, plus his other posts get my brain thinking.

Hope this post helps some one some where, if not at least I'll have it for myself :-)Any questions feel free to ask.

-Bill

[SPLScion 3]

I forgot a few things, all the tests were at idle which in a TC is about 600 rpm and with the A/C on, cuz I didn't have the heart to over heat my friend.

I also found a neat trick, after a couple hours it got pretty hot, I cranked on the A/C max defrost and cooled the area around the meter. I left it on for maybe 20 secs or so, then I turned it off and let my volots come back up the 2/10ths it had dropped and hit the mic with everything I had, I gained .2-.3 or so!!! wont work in cool weather perhaps but on a hot summer day... helped alot!

[antonmiller 8]

very interesting! im going to try some of these at my next event.

thanks for the info!

[shizzzon 461]

what is your actual box rise?

Also, if this is Tlab mic, where is meter position exactly and what is the loudest score you have hit on a test tone, not music.

Also what is your amps rated at and how many u got?

just to let u know when i had my 2 12s in the hatchback-

I did a solid 148.0 flat in the driver kick off of 2 2200ds measuring ~2230w TOTAL, about 1115w per amp at a 42hz peak which was daily tuned and not comp use which could have been a lot louder and only 56sqin of port area.

I was able to hit so high because my loading area for the port was in a position that allowed the port to extend all the way around the box.

right now i'm doin just over a 156 in the kick but only a 152.9 at the headrest.

[SPLScion 3]

I've got 2 sub amps one to each sub, wired down to 1 ohm (dual 2 ohm VC's). Each amp has a rise of .8 - .9 ohms so each amp is seing a load of 1.8-1.9 ohms. They are rated at 600w @ 2 ohms and 900w @ 1 ohm. the clamped measurement yesterday was 650 to each sub.

the meter is placed on my windshield, passenger side I haven't measured it but I have a little circular sticker to the placement is the same every time. Its where db-drags place it aout cuz NESPL uses db-drag style classes and and rules including placement. I'll measure it tom. suring the day cuz there is a sick storm going on outside right now, mad lightening and thunder.

The loudest score I have hit on a tone is exactly one db lower then on music so 144.2 (kinda weird but I have been testing with and for music because of my class requirement, music only, all year)

your scores own me lol but I am working on it!

[shizzzon 461]

when u say clamped, is this a guesstimate measurement? was just amperage measured?

For full blown out competition, i can tell u some designs that should blow you away.

There are 3 designs which excel in the loudest designs i tested in the back of the car-

Sub back port back 11" from hatch door was the loudest period!

Next is sub back port up, sub 11" from hatch door.

Last but not least - sub facing to the side (opposite side of where meter is placed) and port back

But, before u start over, you will also need more power!

for budget reasons, put an Audiopipe AP30001D on EACH sub wired at 1 ohm for comp use ONLY.

And also before deciding to do this, i would highly advise that you or someone else get a DMM and ammeter and measure realtime voltage and amperage output from speakers terminals on a single amp on a TEST TONE, the note for your peak(i know u use music but test tone is more stable output) and post the numbers here.

If the actual rise is lower than a full 1 ohm higher, then u will smoke these audiopipe amps, i need to see real numbers here.

[SPLScion 3]

not guesstimate, he used both measurements and did the math so I'll prob. smoke the amps, they aren't 1 ohm stable? bummer.

damn your top 3 designs are nowhere near what I got doh! back to the drawing board I guess, and time to do some shopping.

[fast85_gt 1]

I've got 2 sub amps one to each sub, wired down to 1 ohm (dual 2 ohm VC's). Each amp has a rise of .8 - .9 ohms so each amp is seing a load of 1.8-1.9 ohms. They are rated at 600w @ 2 ohms and 900w @ 1 ohm. the clamped measurement yesterday was 650 to each sub.

the meter is placed on my windshield, passenger side I haven't measured it but I have a little circular sticker to the placement is the same every time. Its where db-drags place it aout cuz NESPL uses db-drag style classes and and rules including placement. I'll measure it tom. suring the day cuz there is a sick storm going on outside right now, mad lightening and thunder.

The loudest score I have hit on a tone is exactly one db lower then on music so 144.2 (kinda weird but I have been testing with and for music because of my class requirement, music only, all year)

your scores own me lol but I am working on it!

im also louder on music i do a 149.9 on a tone and 150.7 on music this was playing juice box by gorilla goe my box is tunud low but i get what you are saying

[shizzzon 461]

it means the tone you are using is either the wrong frequency or the wrong amplitude.