Any sub enclosure experts here?

[andgoodinstalls]

Hi guys. I have an Infinity Kappa Perfect 12VQ, running it in a ported box with the Low-Q, internal volume as per the book. 1.75 cuft with a 14.5x4 inch port. Since round ports aren't easy to make or readily available, I used a software to calculate the same dimensions for a square port.

All in all, I quite like the sound of it and feel that it slams way harder than many many subs much more expensive.

However, i do feel that sometimes the sound is a bit wooly, particularly around the 60hz-80hz range, and that the port might be chuffing.

So, to test it, I made a sealed box, again as per specs and put the sub in that. VERY clean, very tight sound, but inside the trunk I could barely hear it.

So it's back in the ported box now. And yes, it sounds good, I still feel something's missing. Doesn't sound tight enough.

Should I be concerned?

[krieger]

Which amp are you using and is this DVC or SVC?

[andgoodinstalls]

It's an SVC sub 400 rms. Running it bridged on 175 x 2 @ 4ohms.

[andgoodinstalls]

The sub is an svc 400 rms. Powering it bridged from a 175x2 amp @ 4 ohms.

[roms]

It might be a SVC. OP there are two things which are causing this.

Poorly made box and improper crossover points for your sub and mids. Secondly the manufacturer specs are always conservative, as i can see your encl is as per manufacturer specs. The problem when the sub has low Q in ported application is that the senstivity is reduced as the frequencies crawls from the (fb) or system resonance towards 100hz mark.
To cure the problem i would ditch these specs and make a new encl, you can model the sub in Bassbox or WinISD and see what gives you better results, but again this depends on your personal preferences. Just try to keep the f3 high if you intend to blend well with fronts at the expense of bottam end. And if you want SPL than make it 3 cuft @ 32hz

[faraz813]

hi rooms..... i have question what is f3 exactly for box measurement i worked on bassbox pro and build this thing im attaching image can u tell me if im ok on parameters i have 2309 svc's im planing to put in. Thanks

[roms]

hi rooms..... i have question what is f3 exactly for box measurement i worked on bassbox pro and build this thing im attaching image can u tell me if im ok on parameters i have 2309 svc's im planing to put in. Thanks

f3 is basically the 3db ripple from fmax. fmax is refered as a point where the output of sub is maximum. Also why you have put value of QL to 10??
4.16 cuft is too big, you dont need that much. Make a new thread and ask all your questions there.

[faraz813]

Thanks roms for your help and i will make new thread asap.. and i havent put QL value it came up by itself..

[andgoodinstalls]

Thanks! I'm actually very happy with the notes the sub is currently hitting. I've tried a number of other boxes as well, this open sounds the best and most accurate to me.

So perhaps I should rephrase my question, does the woolliness come because of a crappy box or a poor port? I can't make out if this is port chuffing or not because the edges aren't rounded off.

And most importantly, how good are you with this box software? Could you help me explore making a new box????

[andgoodinstalls]

Also, how does one tag another member in a post? I think STJ74 might have some valuable experiences to share.

[andgoodinstalls]

In case anyone is wondering, below are details of my setup in a 2012 Corolla.

Headunit: Pioneer DEH-8450 BT

Front speakers: Focal PS 165 (80 watt rms 4 ohms, dual crossovers)

Rear Speakers: Hertz ESK 165 (100 watt rms 4 ohms)

Front amp: Pioneer PRS-D2100T (150 x 2 rms @ 4 ohms)

Rear amp: Fusion PP-AM16004 (4 x 150 rms 4 ohm) (2 channels bridged give 440 watts rms 4 ohms to the sub)

Subwoofer: Infinity Kappa Perfect VQ 12 SVC (400 watts rms 4 ohms)

Subwoofer enclosure: Ported 1.75 cuft, 14.5x4 port, tuned at 36 hz with Low-Q insert

Front doors have been damped with dynamat and rubber sheets

Rear trunk and parcel shelf has been damped with Closed Cell Foam

RC leads and wiring kit are Stinger Streetkill or Roadkill or something like that.

Speaker wires are Bose.

All in all, I think it's a very clean install, rubber gaskets on the speaker adapters, RC leads, power cables, speaker wires running separately. All the usual do's and dont's have been followed.

Currently, I am running the front Focals on the pioneer amp.

Rear speakers are running on the fusion, with the remaining two channels on that amp bridged to the Infinity sub.

I am using NONE of the filters on the amp, just conservatively tuned gain setting. Have blown too many speakers to push my luck again.

On the head unit, I have the speakers set at 80hz cutoff, with the sub set to cutoff at 125hz at 3db.

The reason I have overlapping frequencies is because the sub produces exceptional low bass, to the point that it dominates the mid bass from the speakers. The frequency overlap helps bridge that gap. It doesn't matter when listening to rock or jazz, but becomes an issue with house music.

As for why I am running the sub on 'full' setting instead of 'LPF' from the amp, well I just don't like the LPF sound.

I realise that the Fusion amp is a weak link in my system, despite being a high-end fusion. For that I plan on getting an Audison Voce 4 channel amp, 120 x 4, and eventually run the 4 speakers off that, and then use the PRS amp on the sub, since it gives a clean 600 watt rms x 1 @ 4 ohms.

On the equalisation, I am running it at almost flat. Just minor tweaks.

Children, comments invited.

[stj174]

AOA,

There could be a number of issues contribution to the problem you have. Such as improper enclosure design, inadequate power, sub's own response or characteristics in the given enclosure or Q used, Speakers out of phase with the sub. Kindly share some pics of the enclosure and the setup, specially the rear fills that way i may be able to give you a better answer.

In the meanwhile, disconnect or turn off the rear speakers (by using fader ?) and run the front speakers and sub only. Check the crossover points and phase between the front speakers and then check the xo point and the phase between the front pair of speakers and the sub. See if this resolves the issue (with no rear speakers). Try 80hz LPF for sub and 80hz HPF for front speakers.

[andgoodinstalls]

Hi there. Thanks for the prompt reply.

All done and done as instructed. I still don't like how my sub sounds on LPF, but for testing purposes I have followed your instructions to the last dot.

Unfortunately, the woofer chuffing problem still remains. Still, after bout 60 Hz the bass just disappears.

Allow me a day or so to send pictures, i suppose we can have a more productive discussion then.

Thanks!

[stj174]

Hi there. Thanks for the prompt reply.

All done and done as instructed. I still don't like how my sub sounds on LPF, but for testing purposes I have followed your instructions to the last dot.

Unfortunately, the woofer chuffing problem still remains. Still, after bout 60 Hz the bass just disappears.

Allow me a day or so to send pictures, i suppose we can have a more productive discussion then.

Thanks!

No problem at all. Waiting for the pics. BTW was there any difference/ improvement in the 80hz region before and after disconnecting the rear speakers? That was what i wanted to know actually.

[andgoodinstalls]

Hi, sorry, it made pretty much no difference in the 80hz region when I had the rear components faded out.

Can you elaborate on what exactly you're trying to assess? Are you trying to see if the fault lies in using the same amp for the sub and rear fill?

I do feel that there was a reduction in the volume of bass once the rear speakers were faded out.

Anyway, pictures coming shortly.

[stj174]

Hi, sorry, it made pretty much no difference in the 80hz region when I had the rear components faded out.

Can you elaborate on what exactly you're trying to assess? Are you trying to see if the fault lies in using the same amp for the sub and rear fill?

I do feel that there was a reduction in the volume of bass once the rear speakers were faded out.

Anyway, pictures coming shortly.

Actually wanted to rule out if we are having phase issues or not. Sometimes the rear fills cancel the bass of the sub, where the sub is pushing the air outwards and the rear speaker is canceling it by pulling it and vice versa (lets just leave that for now).

Probably the issue seems to be with the enclosure design and/or the subwoofer response in a ported enclosure (etc.). @roms bhai used to have the same sub, he will be able to guide you much better than me. He will be able to share with you his own experiences with the sub as well.

[roms]

Understands the basics first, the bass should be upfront, should not be localized from back. You will muddy up frequencies when you try to overlap 12" with 6.5". As Sir STJ suggested, play with phase to blend it with mids. If still not then revisit the design of enclosure.
You should also know that the ported enclosures roll off more abruptly than a sealed enclosure.
If your mids are strong than eq the 60-80hz region to flaten the curve.
Otherwise a new enclosure biuld with an aim to get crsipy 60-80hz region.

[andgoodinstalls]

Hmm… I had suspected as much. To be honest, when i had used this sub in a well made sealed box, I had absolutely no complaints. The problem is, I felt the sub was distorting at higher volumes… and after reducing the gain to a decent level, this sub just isn't loud enough. So, I'll be sticking to a ported box.

Here's where I'm flying blind… I've already got a box as per the manufacturer's specs. The only thing lacking I suppose is having a carpet lining on the inside walls to kill standing waves. Will that help?

Or do I need to make a new box? And if that is the case, then how do I figure out the port and box dimensions?

[madhouse12]

when you say 14.5x4 does it mean you are using a slot port or a round port? share a pic of the box for proper understanding.

if it a round port then your tuning for the box is around 34hz. a box tuned at such a low freq will have trouble playing freqs like 80hz. ur focals can get lower than 80 hz. try them at 63hz from the pre and sub at 80 hz and see how it goes

[andgoodinstalls]

Ok, since pictures seem to be of prime importance, here goes. Pictures of the entire install.

Fusion runs the sub and rear fill speakers. (ESK Hertz). Then the tweeter on the rear parcel shelf is your reference for placement.

Front speakers running on the pioneer PRS.

And the sub box, has a square port.

See I understand what your saying that the bass needs to be adjusted with the crossovers so that the source of the bass can't be traced back to the trunk, it shouldn't be localised. I hear you.

And as a solution to that, it's a simple matter of setting all my comps at 80hz, and setting my sub at 80hz while reducing the bass from the eq. I prefer my music bass heavy and don't mind the bass being localised from the trunk, in any case, point is I understand what you're explaining.

The problem here, or rather concern, is the quality of sound I'm getting from this sub. at 50hz and below, it's brilliant. Great SQ and very loud.

Yes, it IS HITTING 80hz to 150hz, but a really crappy 80hz to 150hz.