strange sound

[steveo50 3]

hey so i got a new 07 trailblazer and a new box for a single death row 12. i have the box built to spec the port looks a little small and thats what im thinking the problem is, but i thought id get some thoughts from yall. i messed with the amp a little to see if that was the problem but it did not seem ot help.well when the sub trys to hit the real low notes it just kinda farts out and sounds like crap. i dont think it is blow cuz it still slams its just the low low notes im having problems with.

Edited January 15, 2011 by steveo50

[cobra93 47]

What are the box/port dimensions?

It sounds like you're trying to play too far below the port tuning, but without more info it's anybodies guess.

[altoncustomtech 773]

Are you POSITIVE it's built to specs? I agree with cobra, it sounds as though you're playing well below tuning with an undersized port.

We'll need dimensions to know for certain. Another possibility is some bad air leaks, maybe.

[w00tah 5]

Below tuning output drops off very quickly. Overexcursion under tuning because of a lack of cone control is a big cause of death for ported subs. Sounds like a combo of the two. Give it a little bit more port and tune it lower. If your amp has a SSF on it, use it, that is what it is there for. Mine is at 25 hertz, tuning is 30. Works out well, and I still have output under 30 hertz without hurting anything.

Kef

[Kanaworm$ 292]

Get us your box and port dimensions then we can make sure everything is correct on your box. Sounds like the subwoofer is unloading.

[steveo50 3]

ok ill go run and do that real fast i was pretty sure the box is built to specs cuz the guy who made it is a really well known box maker around my area and iv heard alot of his boxes. but i will go take a look at it

[steveo50 3]

well here is the out side measurements L-24.5in, W-15in, H-14in the port size is from where the wood ends to make the port. L-14in, W-2in, H-12.5in

[cobra93 47]

well here is the out side measurements L-24.5in, W-15in, H-14in the port size is from where the wood ends to make the port. L-14in, W-2in, H-12.5in

I plugged those dimensions into BBP6. It doesn't figure the port using the outside wall as a port wall so the numbers will only be "in the neighborhood".

I come up with 1.92 c.f. net and ~ 45 hertz tuning, assuming all walls are .75" only.

If the walls are thicker or there is bracing/ 45's in the corners the tuning will be higher.

You didn't state what tuning you were after, but I can only assume you were not expecting it to be that high. Were you?

If you add to the existing port (outside of the box) and increase the port length to 31" total you'd be ~ 33 hertz tuning. 27" total would be ~ 35 hertz tuning.

I other words don't alter the net volume you have now, construct a port ~ 16" in length and screw it to the outside of the box, test and see if it sounds better to you.

You can always trim the port down 1" at a time to achieve the desired tuning/sound you like, then rebuild the box to the new specifications.

Now that you know what your problem is don't be tempted to play the sub until you either change the infrasonic/subsonic filter or fix the box, or you'll kill the sub quickly with that volume knob.

Edited January 16, 2011 by cobra93

[Sir-Lancelot 216]

Sounds like the "reputable installer" put you in a prefab enclosure.

Sucks bro, but yeah that box is tuned to like 43-44hz.

Build your own, contact one of the builders on here, or do like cobra said temporarily extend the port externally.

[steveo50 3]

damn man thats some bull shit!!!! thanks yall, i might try what cobra said but the guy said if i haveany problems he will rebuild the box for free. im not to sure if i want him to now. id makemy own but im really not that handy. i cant live with out the bass should i just tune the filter to a higher hz till i ge this problem taken care of?

[Kanaworm$ 292]

Not enought port area for that series of woofer either.

What are you wanting for tuning?

Contact Bromo here on the forum for a box design. He does great work and I have had him design me enclosures before.

[steveo50 3]

I just wanted about 35 to specs

[steveo50 3]

O yea also does he charge for the design I may take it to the guy and make him build it right this time

[cobra93 47]

I don't know how many ported boxes you've heard before, or what different tunings you've heard/liked for the music you prefer.

If this is "one" of the first, I'd suggest you play with the port length/ tuning with the box you have now before you rebuild.

If the builder stated he'd rebuild the box for free, I'd try to know what I want before I take him up on his offer.

I'd also let him know now that you're not pleased with the current tuning and ask how he came up with the box volume and port length/volume.

If he can't answer those questions, time to move on and learn for yourself.

You'll only get better with practice, trial and error. Everybody has got to start somewhere and we're all still learning.

Good luck with the new box!

[steveo50 3]

Not sure if you care or what not but I like slowed down music with the lows I'm not so much for the punch kinda souund I had a friend with 2 18 in matts in his avalanche I know my one two won't sound like his set up but his was ported

[cobra93 47]

Not sure if you care or what not but I like slowed down music with the lows I'm not so much for the punch kinda souund I had a friend with 2 18 in matts in his avalanche I know my one two won't sound like his set up but his was ported

Allot of us DO care, that's why we're here and what makes thus forum so awesome.

I don't remember what kind of power you have, but you may want to increase the net volume if you have room.

I have heard quite a few people on this forum that have only great things to say about Bromo and his designs.

You may want to do a search for some of his designs/work, it may be a little complicated for your builder, I have no idea as to what your builders skills are.

[ia2 21]

There may be more port length inside the box that you cant see, but it doesnt sound like it. I plugged the box into our program and got 2.25 cubes (before displacement) tuned to 40 hz. Slowed down music sometimes reaches into the sub-30 hz range, and if this is the case, you are playing waaay under tuning and the sub will unload like crazy and sound terrible. For the time being, if your amp has a sub sonic filter, try playing with it and adjust it closer to the box tuning, or at least a bit over 30 hz. Contact the box builder, and get the exact specs of the box, and make adjustments as necessary until you get everything figured out. You dont want to have to buy a recone because of some simple adjustments.

[smashedz28 110]

Bromo is doing free designs right now over on ca-f . he just got done doing one for me, i cant see your 'box builder' having any trouble building bromo's designs. http://www.caraudio-forum.com/forum/forum/34-eclectic-enclosure-designs/ he does accept donations though

[steveo50 3]

Hum thank you very helpful I talked to the box builder and he said that I prob need to mess with the amp but he is willing to listen to it and see if he can tune the amp for me if the sound is still there he will build a new one

[steveo50 3]

wel, i have messed with the filter it was set at 10.i moved it up to 35. my pos brutus amp goes from 10 to 35...well it was set at 10 im kinda thinking that has been the problem. id go try it out but! i feel like drinking beer sooo ill let you know how it goes

[Kanaworm$ 292]

Any updates? Looks like you may have found your problem with the SSF filter being set to low for your tuning. Let us know how it sounds with the SSF filter set higher.

[steveo50 3]

Naw I messed with it still the same problem it has to be the box I have to wait till sunday to talk to the builder see what he wants to do I will deff try a design from bromo

[steveo50 3]

i got bromo to make me a design and i think i may try to make it my self

[steveo50 3]

Ok so I just talked to the box guy. he said that the new box I want build is going to sound even worse then his, he also said the bass note was a 20hz its trying to play and its losing controle of the cone or something he said he would build it to make me happy but said it will not play the songs I wanted unless I had 2 subs or a 15 and that who ever said I needed a bigger port or box is talkin out there ass I of course put in that an ai rep said it was to small he then said what ever I want and will build it for free is he the one taking out his ass?

[cobra93 47]

Ok so I just talked to the box guy. he said that the new box I want build is going to sound even worse then his, he also said the bass note was a 20hz its trying to play and its losing controle of the cone or something he said he would build it to make me happy but said it will not play the songs I wanted unless I had 2 subs or a 15 and that who ever said I needed a bigger port or box is talkin out there ass I of course put in that an ai rep said it was to small he then said what ever I want and will build it for free is he the one taking out his ass?

Well, 24sq." of port for a 2 c.f. net box is within the generally accepted guidelines of 12-16 sq." of port area per cubic foot.

However, Power and excursion have to come into play as well.

A JL 12wo on 125 watts can't require the same amount of port per c.f. as your DP on allot more power, there's allot more air to move.

Where did the 20 hertz note come from and how does he know it's a 20 hertz note?

If you were trying to play a 20 hertz note with the sub/infrasonic filter set incorrectly and the box tuned 30-45 hertz, that's what should happen.

How well do you know this guy?

Maybe I'm odd, different or whatever, but I'm unimpressed when I here someone crap on another product to make theirs look better, rather than simply telling me why their product is better than the other.

I'm no expert here, many others on here have more experience and knowledge than I.

Post the spec.s of Bromos design on your next post and see what others have to say.