15" punch

[kerrystansbury]

I have a 4 way system with a 2x18" subs, 2x15" bass/midbass, 2x8" mids and 2x1" horns on each side. I have tried several different 15" woofers but I can't seem to get that chest pounding punch that I heard coming from other 15" cabinets, especially ones like Carvin LS1523 cabinets. I get the best sound crossing over via a 24db octave 4 way electronic crossover at 50, 350 and 300hz but no matter what drivers I have used and how I tune them I come up with no punch, (that bass that blows in your face and knocks you backwards). I have plenty of floor rattling, pants leg moving deep bass. Are there certain thiele small parameters that I should be looking for that would give me this and what frequency should I tune them to.
The latest 15" I have benn looking at is a Faitalpro 15FH520

FaitalPRO - Professional Loudspeakers Made in Italy


This is a high power system pushing 2400 watts x 2 on the subs and 2000 watts x 2 on the 15"s, any help with this would be deeply appreciated.

[Robh3606]

Try some JBL 2226's, that should give you some kick

Rob

[Xoc1]

What design cabinets are you using at the moment? The 15" drivers are covering quite a large range (Nearly 3 octaves) to reach your 8" drivers.
The Carvin cabinets seem to have quite a high tuned port to be -3db at 49Hz and -10db at 43Hz.

[T101]

Hm, punch you get in two places in the frequency range actually...

The one that hits your stomach is the disco club bass and it is around 40 hz and it is achieved by short disko horns. - so the low punch is obviously a duty of you twin 18's per side...

Thw second one is either the lower spectrum of a solo drum or lower to middle range of male vocalist, that's about 160 to 320 hz

For instance in the album Slowhand of Eric Clapton issued by Backtoblackvinyl there are several places where the punch from the vocal makes you blink - it's very entertaining and I recomend it!
The overal sound is little like: "old durty muddy sound" in the best meaning of that! Lots of Lf - bass guitar, some kick drum and some solo drum punching... Overal it's quite boring album ecept Sally and Cocaine, but entertaining due to the pointed reasons.

So apart from all, what music were you listening when you came to the conclusion that your system lacks punch?

[kerrystansbury]

I have tried JBL 2226 driver and they definitely do not cut it, they don't handle much power and are peaky (200hz) like my 18 sound 15LW1401's that I am presently using. If I crossover higher than 50 hz with the 18's, I lose my kick drum punch (what little I have). some pro sound people suggested crossing over at 80hz, but when I do the bass sound floppy.
The 18 sound 15's I am using have no rich bass guitar what so ever. The 18" cabinets are 8.2 cubic ft. per driver tuned to 33 hz with dual 5" ports, the 15 inch 18 sound drivers are in 4.8 cubic ft. cabinets tuned to 40 hz. I tried tuning them high to get a flatter response and they sounded worse and had less kick drum.
It seems when I went from a 3 way design without 18's to a 4 way design I lost my punch, but the 3 way design just can't handle the bassy dance music. The suspension on my 18 sound 15's is very stiff with a very low VAS and in my opinion probably accounts for the low end roll off. The mms is of 125g and the high Le probably accounts for the high frequency roll off, this is why I am considering the Faitalpro 15FH520 or the Beyma LX60 15 inch drivers. They look very good on Bassbox pro tuned to 40 hz.
As for the crossover point between the 15's and the 8's, 350hz seems to be the best sounding. I do see a mistake in my original post, I crossover between the 8's and the horn at 3khz, not 300hz.
Opinions on my new 15" driver choices, tuning frequencies and crossover points are welcome.
Thanks, Kerry

[Michael Chua]

Originally Posted by kerrystansbury

I have tried several different 15" woofers but I can't seem to get that chest pounding punch that I heard coming from other 15" cabinets..... but no matter what drivers I have used and how I tune them I come up with no punch, (that bass that blows in your face and knocks you backwards). I have plenty of floor rattling, pants leg moving deep bass.

Hi Kerry

Try reversing the polarity of the 18" subs. They could be canceling your mid-bass.

Regards
Mike

[kerrystansbury]

I did that a while back and did get some improvement, which is strange since my electronic crossover is 24db per octave which should create a 360 degree shift and still use standard polarity. I also checked to make sure all of the speakers were wired correctly with a 1.5 volt battery.
Thanks

[Michael Chua]

I know, in theory it's not supposed to but it does. I can't explain it but it works for me.

With your 18s polarity now reversed, try moving your 18s crossover upwards from 50Hz to 70Hz. You may just get a stronger "kick" at the mid-bass somewhere in between.

Mike

[kerrystansbury]

I have already tried that, the only other explanation might be time alignment. Maybe I can move the 15's seperate from the rest of the system to check since I don't have a digital crossover. What amazes me is that my little computer speakers (Creative) with their little 8" cube subwoofer has really nice punchy bass, no floor shaking 30hz stuff but nice bass.
Kerry

[Michael Chua]

For that kind of punch, you'll need some bass boost at about 100Hz. At least 6dB.

Mike