Annoying peak with longer port.

[jbop]

I'm new so, Hi everyone.

Im using a pair of Seas P25REXDD as drivers in my subs, and I recently made an effort to improve tightness by installing a longer port in my old cabinets. What has happened is that I got an improvement in tightness, but at the same time I had what appears to be a peak somwhere in the lower regions.

I'm wondering if this peak comes from the box being more of a closed cabinet as I increased the port length and that the peak could be the resonance point the setup would have if I removed the port.

Does anyone have a suggestion as to how I should proceed?
I wish to keep the tightness and get rid of the peak in an easy and cheap way.

[GM]

Greets!

Sounds like the pipe's long enough for its 1/2 WL harmonics to become audible, which will require some form of damping, lowering output a bit in the process. It may be better to revert to the original vent length and damp it as required to 'kill two birds with one stone'.

GM

[Cal Weldon]

While I certainly can't compare with GM's knowledge, when the bass sounds loose or chuffey, I say "put a sock in it" I think he's correct in suggesting reverting to the original port and damping it.

[GM]

LOL! That was my first response, but decided it was too flippant!

[sreten]

Hi,

Try reverting to the original port and lining it (not blocking it) with foam.

Usually need an oblong around 8mm / 3/8" thick x 3(diam) x length.

sreten.

[jbop]

Okay, so what seems to be the general opinion is that I should revert to my old pipe, and increase the amount of damping I use.
Hmm....
I was thinking more along the line of putting a notch filter on it to dampen the peak. I seem to get a good frequency response except for this peak wich colours the bass range.

[tinitus]

If I am not mistaken your driver has a Qts of 0.44, which in BR would need a BIG box, to avoid peaking ... and with xo above 40hz, and additional room gain ..... who knows what might happen

Question is ... how low can you push a driver like this, without loss of control

[jbop]

The more I reengage in this project the more I remember how I thought when the subs came to be in the first place. The box size is around 60l wich is optimal for this driver in a closed box application, but then after a while I added a vent just to see what happened.
Without the extra amplifier, and the added output level the problems I experience now weren't that noticeable. They are now however..... Ugh.

Perhaps I should plan for a new cabinet. The ones I have now are ugly anyway.( Extremely ugly according to some.)

Are the Seas drivers I have worth the effort, anyone?

[tinitus]

Have you experimented enough with level and xo settings ?

What kind of subamps do you have ?

Which music do you play mostly, and at which level ?

What are your expectations ?

What are your main speakers and amp ?

Do you play analogue records or only CDs ?

[GM]

Greets!

Don't have the specs for the P25REXDD, only the P25REX, but assuming it's fairly close it's suitable for either a MLTL or pipe horn sub if you can tolerate the size.

GM