Hope It's Not Too Low

[VWBobby 10+ year member]

doublepost lag

 

[iLL Ridge 10+ year member]

Astro's got a tune at around 50-60hz, big hump there, so I like to cross the subs over at 50 or so to kill the boominess. The DB drive plays the higher 60-80hz notes loud but it sounds like **** up there. The opti's are way cleaner at high volume up there. Neither has the sub 30 sound I'm looking for.

 

[audioholic 5,000+ posts]

28hz is fine to tune to, generally speaking. I wouldn't go much lower than that for car audio however.

 

[RAM_Designs 5,000+ posts]

My 28hz box is still too loud above 60hz or so...can't even think about crossing my sub at 80hz because certain bass guitar stuff is too out of balance that high. 63hz with a 12db/oct crossover works great, with another 12db filter at around 100hz at the sub amp. That blends much better with my mids.

 

[audioholic 5,000+ posts]

Well lets not forget that speaker inductance plays a role as well as enclosure tuning.

 

[Cruzer 10+ year member]

AE AV 15 has low inductance, low distortion, and gets just as loud as a fi q

 

[72 chevy van 10+ year member]

I have 2 kicker cvr 12's in 4.5 cubes at 28hz and man for cvrs it sounds nice and clean gets low and is louder than my old box wich was 3.5 cubes at 38hz i love it. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

 

[05fronty 5,000+ posts]

maybe sa-15?

 

[Kyle_Keating 10+ year member]

A lot of music has content below 20Hz now days. Most users tune boxes TOO high in attempt to gain output and it does work, but the problem is you only gain output near tuning so you end up with peaks in the response. Take a look at this example.

purp line is 5 cubes tuned to 20

orange line is 5 cubes tuned to 30

green is 2.5 cubes to 30

only the purple is a good alignment because the rest are high Q and you wont hear the upper bass because of the added SPL down around tuning. Lots of people go for the large box high tune (and in this case, 30Hz is not even that high, but look at what is does to the response) This 15" woofer has a Qts of only about 0.4. If its lower this effect gets even worse and many woofers have lower Q's.

If you want a little boost around 30Hz and don't care for too much output below without giving up sound quality then in that case you actually need a smaller 3.75 cubic foot box tuned around 23Hz (much lower then you think). Which looks like the green line which is a good enhanced Q alignment without too much boom.

These numbers i'm throwing around are different for all woofers and in this case i tried to pick a pretty standard 15" so its somewhat applicable. but the best thing to do is model the design ins WinISD - which is free and pretty easy to use.

 

[adio 5,000+ posts]

Well lets not forget that speaker inductance plays a role as well as enclosure tuning.

i wonder if that was the case with me......

 

[T3mpest 10+ year member]

Good post Kyle. Alot of times we can use smaller portex boxes than we think that we should be able to for SQ, especially with some mid to low q woofers. By shrining the box size and tuning low we still get a falling response for SQ, but get the excurison damping benefits of a ported box. My 15" woofers are in 2.3 cubes a peice tuned to 25hz for this reason, they are lower q.