Very peaky performance

[wu36ca 10+ year member]

So I finally got an amp that actually works to push my RE SE. It is a Kicker 750.1. I am not quite satisfied with the performance I am getting. The box I am using is 2.71ft^3 gross, with a port size 2x13x28. The sub displacement is .15ft^3 and the result should be a net volume of ~2ft^3 and a port tuning of ~32 factoring rounding error. I understand ported boxes are not fully flat in response, but this box is extremely peaky. My main concern is the roll off occurs rather immediately. It plays those low lows, the mid to low 30hz frequencies with real authority. It starts to drop off from there and once it gets to I would say the high 40hz to low 50hz range and beyond it drops off significantly to the point where I cannot even hear the bass. I am assuming the box is the culprit. I just wanted to know what characteristics of the box would cause performance like this.

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[psych0ticnemes1 5,000+ posts]

how could it sound peaky if it doesn't play the higher notes?

 

[PhatTonyDeMarco 5,000+ posts]

how could it sound peaky if it doesn't play the higher notes?

'Peaky' does not mean it peaks in the higher frequency range, it simply means it peaks somewhere and has a steep drop off. In his case, he has the low end but is missing the upper subsonic range...

Is this box for a 12, or a 15? If it is a 15, then the enclosure is too small. If it is for a 12, then you possibley screwed up your calculations and tuned too low? I am just assuming, I do not feel like figuring out exactly what the box is tuned to...

 

[wu36ca 10+ year member]

I assumed that is what it meant when response wasn't flat. Well anyway, words aside, I get way better performance on the real lows than the higher notes. Its really weird. I know most ported box shine on the higher notes, but it is the other way around for me.

 

[wu36ca 10+ year member]

It is for a 12. I used WinISD Beta I believe. Either way, Alpha and Beta gave me different tuning frequencies for these dimensions. So its either 29hz or 32hz depending on which program. I thought, even if it is tuned real low it would get more of the characterstics of a sealed box. But there is too much of a discrepancy for that.

 

[PhatTonyDeMarco 5,000+ posts]

I assumed that is what it meant when response wasn't flat. Well anyway, words aside, I get way better performance on the real lows than the higher notes. Its really weird. I know most ported box shine on the higher notes, but it is the other way around for me.

It depends on the enclosure..

Every ported enclosure has a peak frequency, as well as a drop off at some point. Generally, the larger the enclosure the flatter the response; to a certain extent. So, I can suggest going a bit larger and tuning a bit higher and see what you get. Don't worry man, before long you should be used to building new enclosures with this hobby

 

[wu36ca 10+ year member]

Well I guess setting the crossover on the HU above 50hz helps. There was a much noticable difference, but there still seems to be a pretty hefty discrepancy. Songs with real boomy type bass (ie Still Fly by Big Tymers) kind of lack on the kick drums. But I am getting more satisfied. Hopefully it will get better as the sub breaks in.

 

[audioholic 5,000+ posts]

Well I guess setting the crossover on the HU above 50hz helps. There was a much noticable difference, but there still seems to be a pretty hefty discrepancy. Songs with real boomy type bass (ie Still Fly by Big Tymers) kind of lack on the kick drums. But I am getting more satisfied. Hopefully it will get better as the sub breaks in.

I was going to say... there's no way simply tuning the enclosure to the low 30's (or even hgh 20's) should show a roll-off point like that. There should be no problem extending well into the midbass territory. And it wouldn't roll off steep enough to have virtually no output while still being in the subbass range, no way. A bandpass box yes, a simple vented box... no way. That only sounds like a crossover setting problem. Now that you have the H/U set correctly, do you have actual output up to 80-120hz or more? You should, if not, try checking your amp's xover etc.

 

[mannyb18b]

sound like a x-over problem. What was the crossover point on the deck before you changed it

 

[wu36ca 10+ year member]

I set it to 80hz.

 

[mannyb18b]

set the headunit xover at full range...meaning don't cross it over at all. Just use the xover points on the amp.

 

[Immacomputer 10+ year member]

It could be a number of things. Usually making an enclosure larger will cause a loss in upper frequency extension while boosting the low end. This usually always happens with subs that are underdamped and more suited for sealed enclosures. If I remember correctly, the SEs have an EBP that leads them to be more suited for sealed enclosures.

The problem could also be related to your vehicle. I had a 240sx that was terrible for anything above 55hz. With the sub outiside the car, there was no problem. You could try firing the sub in different directions to see if this helps. Also, try just turning off your crossovers.

 

[SQBubble 10+ year member]

It could be a number of things. Usually making an enclosure larger will cause a loss in upper frequency extension while boosting the low end. This usually always happens with subs that are underdamped and more suited for sealed enclosures. If I remember correctly, the SEs have an EBP that leads them to be more suited for sealed enclosures.
The problem could also be related to your vehicle. I had a 240sx that was terrible for anything above 55hz. With the sub outiside the car, there was no problem. You could try firing the sub in different directions to see if this helps. Also, try just turning off your crossovers.

i agree. had the same type of sound with my 15, it was because the box was too big... make a smaller enclosure, and the sound should be tight and punchy.