Shallow mount vs 8 inch vs radical modification

[Buck 5,000+ posts]

A lot of the hiphop and electronica I listen to drops to 30.

My buddy says I should just raise my rear seats and get two forward facing 10W7s instead of a bunch of 8s. Not sure what I'm going to do, I really really appreciate the comments in this thread though. I have about a month to plan it out so I'm going to take my time.

What happens with seats usually is the top is angled backwards, and motors hit the top angled piece. You really need to make sure that doesn’t happen with bigger woofers. A lot of 8’s have huge motors compared to their cutout diameter, so watch out on your depth.

I listen to a ton of electronic music, and yes, electronic music has some of the widest bandwidth bass. I’ve done many underseat boxes and designs, and 4 beefy 8’s or similar barely fits, with the motors. I’ve done underseat bandpass boxes, even, both 4th and series 6th orders. You’ll be able to play down to 30 hz and probably lower, if you tune the box correctly and all, with just a ported. I really think the SSA 8’s are the quickest or easiest way you could do this, but fitting 10’s is awesome, if you can realistically fit them. The SSA 8’s have 19 mm xmax iirc and only want .55 cubes per 8, so you can do 4 in about 2.2 cubes and that’s not nearly as hard to fit as say 4 8’s that want .75+ cubes per woofer, and they have a 32 Fs or so, which should really be good for what you want, IMO.

 

[Buck 5,000+ posts]

And you might look at Dayton’s 10’s if you’re considering 10’s.

 

[hispls 5,000+ posts]

My buddy says I should just raise my rear seats and get two forward facing 10W7s

How much volume can you get with whatever off-the-shelf seat lift is out there? Will that be enough? Cramming too much cone area into too little airspace is just as sure a recipe for failure as anything. I like the W7 but if you're looking for a good sounding 1000W high excursion sub I'd take the Adire Brahma over W7.

Do you listen to slowed down or modified music? Can you name a few songs that have 30hz material in them? Low tuning in tiny boxes may prove impractical. Either you skimp on port area and lose efficiency/wind up with port turbulence, or worse, or you wind up needing to eat up half your gross airspace just trying to fit enough air mass in the port. Hoffman's Iron Law will not be bent or broken.

 

[hispls 5,000+ posts]

What happens with seats usually is the top is angled backwards, and motors hit the top angled piece. You really need to make sure that doesn’t happen with bigger woofers. A lot of 8’s have huge motors compared to their cutout diameter, so watch out on your depth.

My thoughts as well when looking at some of those subs posted in this thread.

 

[Buck 5,000+ posts]

My thoughts as well when looking at some of those subs posted in this thread.

I seem to be a magnet for getting some the most difficult underseat boxes, lol. This is basically the largest issue I come across is actually fitting the subs inside of the box. It’s almost always an issue, when trying to fit 8’s under rear seats like this. You also gotta watch out for the motors hitting the port wall of a side firing port (smaller ported box requirements also make smaller ports easier to fit).

I always encourage people to give themselves plenty of space, where neither the subs nor box layout causes jamming issues, where things are running into each other. Sometimes things seem like they’ll fit, then something just doesn’t fit by like .25” right when you go to design it. Underseat boxes are harder, in some cases, than b or c pillar walls, at least ones I’ve done.

 

[Jimi77 5,000+ posts]

I've seen some pretty simple seat lifts - just 4 aluminum blocks. So if you can fit 10's going that route, why not. Although, I'd look at solutions outside JL. Not there is anything wrong with JL and their customer support is second to none, but you are also paying a premium for JL and the w7 is really deep. Lastly, look into rear firing, that generally gets the best SPL/sound.

All that said, there are plenty of kick arse 8's today. You can get around long port issues by going with a passive radiator. The Earthquake SLAPS passive radiators are well respected, affordable and have 2.75" of throw.

 

[Bobbytwonames 5,000+ posts]

Sensitivity under 80..

I wonder if the OP plans on beefing up his electrical that he will need to run 2-3K watts.

I saw that too. I'm not sure how much weight to put on that. I know that it weighs 30 pounds which is a big ass 8" sub. I wish I knew the mounting depth.

 

[Bobbytwonames 5,000+ posts]

I've seen some pretty simple seat lifts - just 4 aluminum blocks. So if you can fit 10's going that route, why not. Although, I'd look at solutions outside JL. Not there is anything wrong with JL and their customer support is second to none, but you are also paying a premium for JL and the w7 is really deep. Lastly, look into rear firing, that generally gets the best SPL/sound.

All that said, there are plenty of kick arse 8's today. You can get around long port issues by going with a passive radiator. The Earthquake SLAPS passive radiators are well respected, affordable and have 2.75" of throw.

You're asking a lot if you want him to fire his subs to the rear in an underseat box. I'm guessing it's near impossible unless you run 6-½'s.

 

[Bobbytwonames 5,000+ posts]

This is about as complicated an under seat ported box can get. This one was for two Sundown X8's. It ported out of both sides. My box builder built it in Vegas. He doesn't use computers. He's been at it since 1983 when he was 13. He built this box in about three hours. Pretty impressive. He used pvc for the aeroprt type ports.

 

[metalheadjoe 10+ year member]

I'd take a shallow 12 over an 8. I liked my Kicker CompRT.

Where are you going to mount the amp?

 

[Bobbytwonames 5,000+ posts]

I'd take a shallow 12 over an 8. I liked my Kicker CompRT.

Where are you going to mount the amp?

Shallow subs ****. You are crazy if you think a shallow 12" sub will outperform a big 8" sub. The JL is the only "decent" sounding shallow sub out there. The DD shallow is probably real good but I've never heard one. You would take a shallow 12" sub over a JL 8W7? You're nucking futs if you answer that question yes.

 

[metalheadjoe 10+ year member]

Shallow subs ****. You are crazy if you think a shallow 12" sub will outperform a big 8" sub. The JL is the only "decent" sounding shallow sub out there. The DD shallow is probably real good but I've never heard one. You would take a shallow 12" sub over a JL 8W7? You're nucking futs if you answer that question yes.

Why is "decent" in quotes? You say JL is the ONLY decent shallow sub, but you haven't heard the DD shallow (or many other brands). How can you say what's best if you haven't heard the competition?

Yes, I would take a shallow 12" over an 8". Was my first post ambiguous? I had a 2004 F150 supercrew. I had an 8" L7 under the seat, then I switched to a 12" CompRT. The 12" shallow played lower and louder than the L7.

Not scientific level comparison, but that's how I formed my opinion.

 

[Bobbytwonames 5,000+ posts]

Why is "decent" in quotes? You say JL is the ONLY decent shallow sub, but you haven't heard the DD shallow (or many other brands). How can you say what's best if you haven't heard the competition?

Yes, I would take a shallow 12" over an 8". Was my first post ambiguous? I had a 2004 F150 supercrew. I had an 8" L7 under the seat, then I switched to a 12" CompRT. The 12" shallow played lower and louder than the L7.

Not scientific level comparison, but that's how I formed my opinion.

I've heard two JL shallows in a Toyota and it was "decent" for shallow subs. It was nowhere near a system that really banged. When you switched to a 12" shallow you more than doubled your cone area. That is probably what you heard. Two of my 8's would smoke your shallow 12" sub. And one 12" sub has more cone area than two 8" subs by more than 12%. You are nuts if you think a shallow 12" sub can outperform two nice 8" subs. Meter for meter and frequency for frequency. My 8's peak at 31 hz. What frequency and db. did your 12" shallow hit?

 

[Jimi77 5,000+ posts]

You're asking a lot if you want him to fire his subs to the rear in an underseat box. I'm guessing it's near impossible unless you run 6-½'s.

I can rear fire 8s in my Ridgeline If I wanted to get creative, I might even be able to rear fire 10s. In the OP's case, I probably wouldn't rear fire if it meant running 6.5s.

 

[metalheadjoe 10+ year member]

I've heard two JL shallows in a Toyota and it was "decent" for shallow subs. It was nowhere near a system that really banged. When you switched to a 12" shallow you more than doubled your cone area. That is probably what you heard. Two of my 8's would smoke your shallow 12" sub. And one 12" sub has more cone area than two 8" subs by more than 12%. You are nuts if you think a shallow 12" sub can outperform two nice 8" subs. Meter for meter and frequency for frequency. My 8's peak at 31 hz. What frequency and db. did your 12" shallow hit?

I said, "I'd take a shallow 12 over an 8". ONE 12" shallow verses ONE 8"! Sounds like you agree, since you jumped to two 8's without addressing what I said!