Under seat storage bin capacity measurements for subwoofer selection.

[Ed Venture]

I took the bin out form under the seat of my crew cab to measure it's capacity for subwoofer selection:

It filled up to the brim with exactly 44 cups, or 2.75 gallons, of water which converts to .368 cubic feet. reasonable for an 8" subwoofer, but a challenge for a good deal of 10" units.

Using the measurements from the attached article, you can increase the functional cubic volume by 30% by using 1.5 lbs of polyfill per 1 cubic foot enclosure. So in this case that comes out to .551 lbs of polyfill (.368*1.5) but this only brings the functional cubic volume up to .478 cubic feet, which is much better, but still limiting. If you increase the polyfill to 1.75 lbs per 1 cubic foot of enclosure, you can bring that up to .500 cubic feet, but at the risk of diminishing performance.

The question is: push the limits of a 10" or step down to a more comfortable, but less punchy, 8"? The RF-P3SD4-10 would work with an ideal enclosure size of .5 cubic feet, but I don't feel my amp has enough power to really drive it. The RF-R2SD4-10, on the other hand, would fit nicely with my amp in terms of output but it has an optimal enclosure size of .7 cubic feet, which seems like a stretch.

Thoughts?

Thoughts?

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[Zaph]

That seems like slightly overestimating the effects of polyfill on effective enclosure size. But if you really want to effectively enlarge the enclosure, buy "Acousta-Stuf" and not polyfill pillow stuffing from Walmart. The problem is, nobody buys real wool stuffing, and all the generic "fiberfill" has fibers that are too large to actually absorb. Pack your enclosures with enough of that and it actually decreases effective size. That's why "Acousta-Stuf" was invented.

I see so many people in the car audio world putting their woofers into enclosures that are way too small. What you end up with is boom from high box Qtc and no depth, and it generally doesn't sound decent unless you EQ it back to flat with some form of boost or parametric EQ.

You just have to ask yourself what kind of audio fan you are. Do you care more about loudness and upper bass kick? Go with the 10". Do you care more about bass extension and musicality than output? Go with the 8".

 

[fusseli]

I would look at an Alpine 8" Type S or R if you have room for a full mounting depth woofer. They like small boxes and have much better xmax than others in the same price range.

 

[Ed Venture]

That seems like slightly overestimating the effects of polyfill on effective enclosure size. But if you really want to effectively enlarge the enclosure, buy "Acousta-Stuf" and not polyfill pillow stuffing from Walmart. The problem is, nobody buys real wool stuffing, and all the generic "fiberfill" has fibers that are too large to actually absorb. Pack your enclosures with enough of that and it actually decreases effective size. That's why "Acousta-Stuf" was invented.

I see so many people in the car audio world putting their woofers into enclosures that are way too small. What you end up with is boom from high box Qtc and no depth, and it generally doesn't sound decent unless you EQ it back to flat with some form of boost or parametric EQ.

You just have to ask yourself what kind of audio fan you are. Do you care more about loudness and upper bass kick? Go with the 10". Do you care more about bass extension and musicality than output? Go with the 8".

Zaph,

I'm not going for bleeding eardrums or a cardiac event from pounding bass. I would just like to have more presence at low to mid-volumes. Bass extension is far more important to me. Also, I want to do this on a budget, so there is that.

Based on your feedback, I'm going to start digging in to 8" subs. Many of them *seem* to be comfortable in enclosure sizes between .3 -.4 cubic feet. However, would you still recommend Acousta-Stuf given the density of the plastic bin and its unusual shape? I plan on wrapping the bin in dynamat (or equivalent) but that can only do so much.

Fusseli,

The Alpine S-W8D4 looks intriguing for my application, but I worry that it may be too much for by amp. I'm only capable of running 180W RMS with a peak of 400W on my current setup. Given that I want to get this done on a budget, I don't want to get a new amp *and* a new sub. Based on your experience with Alpine, do you think 180RMS would be okay or would it be under-powered?

Best,

Ed

 

[Zaph]

That amp would likely be more than the woofer could handle. You can disregard manufacturers power ratings, they are rubbish. Why don't you load the woofer up on a box modeling program and see for yourself? There are some out there for free. I'll do it for you if you want help.

Yes I would still use Acousti-stuf. The stuff works better than fiberfill which sometimes doesn't work well.

 

[Ed Venture]

That amp would likely be more than the woofer could handle. You can disregard manufacturers power ratings, they are rubbish. Why don't you load the woofer up on a box modeling program and see for yourself? There are some out there for free. I'll do it for you if you want help.

Yes I would still use Acousti-stuf. The stuff works better than fiberfill which sometimes doesn't work well.

I didn't realize there are some nice free options. I just downloaded WinISD and will play with it tonight!

 

[Zaph]

WinISD... wow that program is still available. I think I used it 15 years ago. You should be able to change power input level and then look at where your Xmax is vs frequency. Have fun playing!

You can compare the 10 to the 8 in that enclosure volume. What you'll see is the 10 will have very good power handling but poor low end response and peaky upper bass. The 8 will have less power handling but probably better low end extension and less peaky upper bass.

Play around enough and you can pretty much see all your trade-offs.

 

[fusseli]

@Ed Venture
Yeah 180 watts would be enough for some good bass, I don't think it would be lacking. Assuming the sub in the system could handle it, doubling the power is only worth 3 dB of more SPL.

I love WinISD, it's handy and easy once you learn it. WBCD is good too, which is Excel based. Both are free you just need the parameters for your sub driver.

 

[deton8r]

There are a few 10" subs designed and engineered to work well in extremely small enclosures like the Focal Sub P 25 FSE (.28 cu ft), the JL 10TW1 (.35 cu ft), one of the older Memphis Audio shallow Reference series (.35 cu ft), Dayton Audio LS10-44 (.45 cu ft), etc.

 

[P. A. Schilke]

There are a few 10" subs designed and engineered to work well in extremely small enclosures like the Focal Sub P 25 FSE (.28 cu ft), the JL 10TW1 (.35 cu ft), one of the older Memphis Audio shallow Reference series (.35 cu ft), Dayton Audio LS10-44 (.45 cu ft), etc.

Hi Det,

When we did the Ranger Tremor back in 2002, we had a 10" sub. Our first prototype installed the Sub in this giant blowmolded cavity behind the Super Cab seats, attached to the floor. (on line build was S/C seat delete) Anyway we cranked up the volume and it was not too long that the sub crapped out. So back to the sub supplier. This was when we found that the sub was designed to work in a volume of 1 cu. ft! We had about somewhere around 10 cu. ft. So now what...we needed to reduce the volume of this blowmolded cavity. This is when we decided to stuff the cavity with blocks of foam to obtain 1 cu. ft. It worked!

Tremor was done as an off line operation in a maintenance shed at the Edison Assembly plant.

Here is an article on the Tremor:

https://www.autotrader.com/car-news...gift-audiophiles-who-also-needed-truck-268350

best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[fusseli]

There are a few 10" subs designed and engineered to work well in extremely small enclosures like the Focal Sub P 25 FSE (.28 cu ft), the JL 10TW1 (.35 cu ft), one of the older Memphis Audio shallow Reference series (.35 cu ft), Dayton Audio LS10-44 (.45 cu ft), etc.

The JL 10TW1 is like the Alpine SWRT10, both are 4 ohm so a single one for the Ranger is not an efficient setup for amplifier choice. This is why I am looking at the Alpine S-W8D4, since it is just as thin and can be ran at 2 ohms and likes the small volumes like 0.3 cuft.

 

[fusseli]

Hi Det,

When we did the Ranger Tremor back in 2002, we had a 10" sub. Our first prototype installed the Sub in this giant blowmolded cavity behind the Super Cab seats, attached to the floor. (on line build was S/C seat delete) Anyway we cranked up the volume and it was not too long that the sub crapped out. So back to the sub supplier. This was when we found that the sub was designed to work in a volume of 1 cu. ft! We had about somewhere around 10 cu. ft. So now what...we needed to reduce the volume of this blowmolded cavity. This is when we decided to stuff the cavity with blocks of foam to obtain 1 cu. ft. It worked!

Tremor was done as an off line operation in a maintenance shed at the Edison Assembly plant.

Here is an article on the Tremor:

https://www.autotrader.com/car-news...gift-audiophiles-who-also-needed-truck-268350

best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

So the Tremor used the space between the frame rails under the chassis for that huge subwoofer space under the floor?

 

[P. A. Schilke]

So the Tremor used the space between the frame rails under the chassis for that huge subwoofer space under the floor?

Hi Fusseli,

No...all was done inside the cab at the rear. This blowmolded piece looked like a flattened fuel tank. the top surface was like a mini load floor behind the driver and passenger seats. The underside of the blowmolded part was able to take the Amp in the rear footwell. The sub was installed facing down on the other footwell. The whole thing was contained inside the rear of the Supercab except for the head unit in the dash, the huge wiring bundle to the amp and speakers and the heavy duty alternator on the engine . I had a couple Henry Ford Academy high school kids doing their Practicum assignment working for me during the Tremor prototype builds. These kids were blown away by what Ford was doing with the Tremor. I can't say for sure from an audiophile standpoint how good this package was, but I can say that my experience being annoyed by the overpowering base of other vehicles sound system vibrating my internal organs, the Tremor held its ground at any stoplight...

At the time, we had to run the standard CD skip test on the Pioneer head unit. It barely met the Ford requirements for skip.... Sure made me aware of the quality of Ford radios.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[Wayne Kubeck]

I took the bin out form under the seat of my crew cab to measure it's capacity for subwoofer selection:

It filled up to the brim with exactly 44 cups, or 2.75 gallons, of water which converts to .368 cubic feet. reasonable for an 8" subwoofer, but a challenge for a good deal of 10" units.

Using the measurements from the attached article, you can increase the functional cubic volume by 30% by using 1.5 lbs of polyfill per 1 cubic foot enclosure. So in this case that comes out to .551 lbs of polyfill (.368*1.5) but this only brings the functional cubic volume up to .478 cubic feet, which is much better, but still limiting. If you increase the polyfill to 1.75 lbs per 1 cubic foot of enclosure, you can bring that up to .500 cubic feet, but at the risk of diminishing performance.

The question is: push the limits of a 10" or step down to a more comfortable, but less punchy, 8"? The RF-P3SD4-10 would work with an ideal enclosure size of .5 cubic feet, but I don't feel my amp has enough power to really drive it. The RF-R2SD4-10, on the other hand, would fit nicely with my amp in terms of output but it has an optimal enclosure size of .7 cubic feet, which seems like a stretch.

Thoughts?

Thoughts?
I haven't had the chance to pull it out yet, but what dies it look like with the bin removed? Probably just use the existing space and fab up a cover with a woofer cut out?

 

[P. A. Schilke]

Hi Wayne,

I rarely comment on these type of mods...I am not an audiofile as when driving I concentrate on driving...Just me...okay...

What I might suggest based on the Ranger Tremor that I developed is maybe raise the surrounding area of the back seat cavity if possible. you might be able to install a simple rectangular section made out of wood for example that increases the volume for the 10" sub. If still at Ford, we had this clay like material called DumDum. We could clay this up...slam the seat, raise it and the measure the depression to see what clearance is available. Modeling clay might work here as well. Make thick worms of this material by rubbing your hands together to grow these worms. Maybe lay worm on top of worm... I am betting you can gain the volume you need, taking advantage of the under seat space.... This is just a thought and may go down in flames as I have not researched this as my B&O system is very nice for me with my poor hearing thanks to screaming Indy Cars for some 22 years of which I was a track side Race Control Official. (yes, hearing aids are in my future, but I resist. Wife claims selective hearing...um...maybe true to a point....)

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

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