Ported + Cabin Gain = Good SQ?

[Mdjai 10+ year member]

I dont know how my link got messed up, but here it is again, and it should work now:

http://www.imagedynamicsusa.com/pdf/IDMAX10%20V3%20D4%20spec.pdf

And it does recommend 25hz tunning.

Plus I own 2 of them, and the sheet that comes with them recommends tunning to 25hz too //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Mdjai 10+ year member]

I got that from the wording of your title. It clearly appears as though you were considering that. If not, I misunderstoodd you

nah, u misunderstood me.

I titled the thread that because I've read posts of people saying they have a ported setup that has good sound quality. And I couldnt understand how the output near tunning and cabin gain could make it sound good, as far as the sound being "flat". Thats why it is ended with a question mark, bcuz i couldnt understand that //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[liftedcj7on44s 10+ year member]

i have a idmax 12 in 2.5 cubes@34hz off a sundown saz-1500d. I was really surprised at the output i got but i am very dissapointed in the upper frequency extension. If i did it all over again id go 2 12's sealed. and yes i have my lpf up around 80.

 

[audioholic 5,000+ posts]

I dont know how my link got messed up, but here it is again, and it should work now:
http://www.imagedynamicsusa.com/pdf/IDMAX10%20V3%20D4%20spec.pdf

And it does recommend 25hz tunning.

Plus I own 2 of them, and the sheet that comes with them recommends tunning to 25hz too //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Wow, my mistake. That's weird, they dont recommend below 28hz for the 12... and 25hz is too low for car audio, even 28hz is getting down there. A vehicle's transfer function should make up for any roll off below that point. But you're right, I see they recommend it, my apologies.

Weird.

 

[Mdjai 10+ year member]

i have a idmax 12 in 2.5 cubes@34hz off a sundown saz-1500d. I was really surprised at the output i got but i am very dissapointed in the upper frequency extension.

See, now that is one of the thingz that i dont want. My old 15A was like that. the low bass was super, but the upper frequency were just plain SOFT. Aw man, i hope that isnt what my setup is going to sound like.

So, you do you think that it sounds like that because its ported which tends to make the low-end heavy in comparison to the upper bass?

Or do you think its the subwoofer?

Hey, thanx for your response //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Mdjai 10+ year member]

Wow, my mistake. That's weird, they dont recommend below 28hz for the 12... and 25hz is too low for car audio, even 28hz is getting down there. A vehicle's transfer function should make up for any roll off below that point. But you're right, I see they recommend it, my apologies.
Weird.

Yeah, i totally dont understand why they recommend tunning the 10" enclosure lower than the 12" enclosure either.

When i punch in 28hz into WinISD Pro that nast hump shows up, lol. But if i go ported i REALLY do NOT want to tune to 25hz, that IS low. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Mdjai 10+ year member]

If I go with the IDMAXs ported, I would probably have the enclosure tuned to 30hz.

WinISD shows a hump in response on the "transfer magnitude" graph, but it shows that from 31-80hz it varies no more than about 1db in the "SPL" and "Max SPL" graph, which is fine with me. Though the cabin gain will probably boost the low-end to the point where it is signifcantly louder than the upper frequencies that are around 75- 80hz.

Hmmmm. I'm leaning towards ported due to the efficiency, but I still will have to weigh it out. And any additional comments are appreciated, thanx //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[audioholic 5,000+ posts]

Ive heard people complain about the low end response of IDMax's, but upper freq response has always been considered one of their strong points. Ive never owned a Max to play around with however.

Generally ID knows what they are talking about, the people they have working there are top-notch. Try calling them and see what they say, you're liable to get Matt Boguart or some other amazing SQ guy in person. I cant say enough good things about the responses Ive had when contacting ID for a question.

Good luck man.

 

[Mdjai 10+ year member]

Ive heard people complain about the low end response of IDMax's, but upper freq response has always been considered one of their strong points. Ive never owned a Max to play around with however.
Generally ID knows what they are talking about, the people they have working there are top-notch. Try calling them and see what they say, you're liable to get Matt Boguart or some other amazing SQ guy in person. I cant say enough good things about the responses Ive had when contacting ID for a question.

Good luck man.

Will do, thanx //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[liftedcj7on44s 10+ year member]

yeah well my idmax is crazy sick in the lows but the upper end is almost like not there. a ported box is naturally going to have a slow roll off above and below the tuning frequency. it depends alot on the install and the vehicle. it may be just that my car and the size of my trunk just doesnt do well for the upper end. But just be cautious if you go ported and tune low then expect the upper end to roll off and it may not be what you expect. also as audioholic says ID tech is awesome. when i call matt, jim and eric huddle around the phone and put it on speaker phone and help me out, they are great guys. But remember not every car is the same every car has a different frequency that it likes.

 

[helotaxi 5,000+ posts]

A ported box does not naturally roll off except below tuning. Cabin gain isn't going to help that roll off much either. Chances are that you're getting into the subsonic region before it is an issue anyway. Upper bass response shouldn't suffer in a flat tuned box because of the tuning, either.

Your hearing isn't linear. It rolls off pretty heavy on the bottom end. The graph of the response won't look straight in-car it will have hump at the lowest freqs. This matches rather well with the way your hearing rolls off. Once you get into the 30's and below the bass becomes more of a tactile sensation than an auditory one. The low bass needs to be louder in comparison to the rest to sound right. This becomes even more important once you add road noise to the equation.

If the higher tuning is giving you a nasty peak in the response, try going with a smaller box. That will help tame the peak.

 

[Mdjai 10+ year member]

yeah well my idmax is crazy sick in the lows but the upper end is almost like not there. a ported box is naturally going to have a slow roll off above and below the tuning frequency. it depends alot on the install and the vehicle. it may be just that my car and the size of my trunk just doesnt do well for the upper end. But just be cautious if you go ported and tune low then expect the upper end to roll off and it may not be what you expect. also as audioholic says ID tech is awesome. when i call matt, jim and eric huddle around the phone and put it on speaker phone and help me out, they are great guys. But remember not every car is the same every car has a different frequency that it likes.

Can you please give me their number?

The number on the sheet that came with my subs doesnt work anymore.

I'd sure appreciate it, thanx //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Mdjai 10+ year member]

A ported box does not naturally roll off except below tuning. Cabin gain isn't going to help that roll off much either. Chances are that you're getting into the subsonic region before it is an issue anyway. Upper bass response shouldn't suffer in a flat tuned box because of the tuning, either.
Your hearing isn't linear. It rolls off pretty heavy on the bottom end. The graph of the response won't look straight in-car it will have hump at the lowest freqs. This matches rather well with the way your hearing rolls off. Once you get into the 30's and below the bass becomes more of a tactile sensation than an auditory one. The low bass needs to be louder in comparison to the rest to sound right. This becomes even more important once you add road noise to the equation.

If the higher tuning is giving you a nasty peak in the response, try going with a smaller box. That will help tame the peak.

Wow, thank you for your help //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

What do you think about a 30hz tuning?

 

[JonJT 10+ year member]

A ported box does not naturally roll off except below tuning. Cabin gain isn't going to help that roll off much either. Chances are that you're getting into the subsonic region before it is an issue anyway. Upper bass response shouldn't suffer in a flat tuned box because of the tuning, either.
Your hearing isn't linear. It rolls off pretty heavy on the bottom end. The graph of the response won't look straight in-car it will have hump at the lowest freqs. This matches rather well with the way your hearing rolls off. Once you get into the 30's and below the bass becomes more of a tactile sensation than an auditory one. The low bass needs to be louder in comparison to the rest to sound right. This becomes even more important once you add road noise to the equation.

If the higher tuning is giving you a nasty peak in the response, try going with a smaller box. That will help tame the peak.

This happens to be a little contradictory to what you have told me in the past about cabin gain. We had a discussing about applying cabin gain to the design of a sub box. You recommended that I create a transfer function for the vehicle and apply that to the response curve of the box I test. Doing so would negate this low end gain you are effectively implying is needed in car.

Doing what you told me would produce an effectively flat response curve in car down past 30hz. Here you are saying that you need a non linear response curve in car to make up for car noise and your ears logarithmic response. So which is it?

Should we create a sub that is as flat as possible right down to subsonic frequencies by creating a transfer function and applying it to our design? Or tune to around 30hz and alloy cabin gain boost the low end to compensate for road and vehicle noise and our lack of sensitivity for low bass?

 

[helotaxi 5,000+ posts]

^^^Depends on what you want. If you want a flat measured response, sealed will give you that. It will sound a little light on the bottom end with the car running but will still extend into the subsonic at about the same level as the upper bass region that the sub plays.

If you want a system to listen to, don't get wrapped up about it playing exactly flat. Mate the subs with a strong midbass and let the sub get going on the bottom end.

My setup is currently tuned to about 32hz (the cabin effect leaves the effective tuning around 30hz) and the bottom end is not overemphasized at all. Coupled with noisy car, it works out quite well, in fact.

Getting a balanced transition between the midbass and the sub bass is going to do more for getting it to sound right than worrying about it measuring exactly flat. If you are running several big subs and a lot of power, it doesn't matter how flat the sub bass measures it's going to sound wrong for the simple reason that it will completely overpower the rest of the system. On the other hand a single sub can mate nicely with the front stage and a gradual hump in the sub bass is hardly going to be noticed.

Knowing what the transfer function is going to do for you allows you to shape the sound of the sub stage. It gives you the freedom to run a sealed setup with a relatively high F3 and still have output in the very low freqs. It also allows you to run a system that plays flat in free space and get some free output on the bottom end to help overcome road noise. The point is the hump isn't going to ruin the sound.