SSD 18

[mr mikey 0]

After first seeing the specs on the website, I noticed there are a few necessary specs not included.

#1: I noticed the xmax, but nowhere did I see the xlim.

#2: Recommended type of port(s)? (shape/size/depth)

If I list the specs of my vehicle, maybe someone can get an idea and throw me some info. If any other info is needed, just ask.

1995 GMC Sierra LT ext cab 6.5ft bed. Rear seat bottom and back will be removed. .75" MDF enclosure with internal dimensions of 45"W x 30"H x 25"D. Subs will be up-firing. Should ports be front, rear, up or side firing? Where should the ports be located in terms of speaker location, between subs, at corners, etc? I will be aiming for 32.5Hz, so any experience in that frequency range with these subs would be greatly appreciated. They will be ran at 1200watts with BP Power upgrade.

I am having an old PA-1000 rebuilt at a local vocational school with all new boards/parts(just using the old lexan case cuz of it's looks/internal lighting) to run these 2 subs. I'm told they can make the amp stable at .74ohms outputting ~3.8k watts RMS, if it turns out to be a success, then atleast the amp won't be run hard.

0ga wire, Stinger 50farad cell, 2x Optima red tops, twin 200amp alts(small pulleys), and digital meters to keep an eye on usage.

Can't think of any other info that may be needed at the moment.

Thanks for any input,

Mike.

[cheese20323 13]

Xmax: 21mm

16 to 18 sq inches of port area per cuft.

[Bob345 39]

By xlim do you men it's mechanical liners? If so, it's not needed to do prety much anything

[mr mikey 0]

By xlim do you men it's mechanical liners? If so, it's not needed to do prety much anything

For instance, the xmax is the farthest it will move in 1 direction before distorting. The xlim is the farthest it will move while distorting. Usually the excursion is either stopped by the excursion limiters(whether it be the spiders or the limiting-ties), or on older/cheaper subs it's stopped when the coil bottoms out(or in rare cases the coil jumping off the pole).

Some subs have a small xmax whilst having a giant xlim, so that you can option to drive them hard(move alot of cone area) without the coils crashing. The bad thing about spiders limiting the travel is when you have the embedded tensil leads, it can cause unnecessary strain on them during excessive cone travel(excursion).

I just found a site showing how xmax and xlim are defined, you can take a look if you want to know what I'm referring to.

http://www.subwoofer-builder.com/xmax.htm

[Julian 641]

Shape of port typically doesn't matter as long as you have sufficient port area for the woofers the only exception to this is when using Aeroports. With aeroports you can use 30-40% less area and not have any port noise. The 16-18 In^2 is just a rule of thumb you should really look at the exact port area a simple online calculator like (This) will tell you how much you really need... for two 18's you will need at a minimum of 212.6 in^2 of port area. You do not need to worry about Xlim, you will know when your subwoofer is reaching its mechanical limits by listening it is very obvious when it is.

[ssh 924]

By xlim do you men it's mechanical liners? If so, it's not needed to do prety much anything

For instance, the xmax is the farthest it will move in 1 direction before distorting. The xlim is the farthest it will move while distorting. Usually the excursion is either stopped by the excursion limiters(whether it be the spiders or the limiting-ties), or on older/cheaper subs it's stopped when the coil bottoms out(or in rare cases the coil jumping off the pole).

Some subs have a small xmax whilst having a giant xlim, so that you can option to drive them hard(move alot of cone area) without the coils crashing. The bad thing about spiders limiting the travel is when you have the embedded tensil leads, it can cause unnecessary strain on them during excessive cone travel(excursion).

I just found a site showing how xmax and xlim are defined, you can take a look if you want to know what I'm referring to.

http://www.subwoofer-builder.com/xmax.htm

So you want to find how far you can push them past their limits? Perhaps you should get a btl.

[Bob345 39]

By xlim do you men it's mechanical liners? If so, it's not needed to do prety much anything

For instance, the xmax is the farthest it will move in 1 direction before distorting. The xlim is the farthest it will move while distorting. Usually the excursion is either stopped by the excursion limiters(whether it be the spiders or the limiting-ties), or on older/cheaper subs it's stopped when the coil bottoms out(or in rare cases the coil jumping off the pole).

Some subs have a small xmax whilst having a giant xlim, so that you can option to drive them hard(move alot of cone area) without the coils crashing. The bad thing about spiders limiting the travel is when you have the embedded tensil leads, it can cause unnecessary strain on them during excessive cone travel(excursion).

I just found a site showing how xmax and xlim are defined, you can take a look if you want to know what I'm referring to.

http://www.subwoofer-builder.com/xmax.htm

So you want to find how far you can push them past their limits? Perhaps you should get a btl.

X2 Edited October 30, 2010 by Bobobass

[mr mikey 0]

I'll eventually get the BTL's, but a local competitor is bringing in more business with a system that I know can be beat without spending the money he did. He's advertising that he can make your vehicle sound just as loud for a mere $2150. Well, according to the db calculations on rockford's site and fi's site, the rf's he's using do not produce as much db's as the ssd's do. So I was planning on using the ssd's to out-perform him in db's, and then pretty much say "you can get louder than him for under $1000". Now of course customers like to see the excursion runs, but they also turn tail and run if they hear any type of chatter/rattle coming from the subs, so was just wondering the limit to get an idea of actual movement. "Stick your head in the window. Your hair's blowing everywhere!!!" That brings back memories of cerwin vega's

I know he's running the P3 15's in the max sized ported enclosure, with twin RF1000.1's.

[mr mikey 0]

Thanks for the calculations Julian, but let me be a tad more specific. Port opening size = square inches(i now know the required size, ty)....port depth = how far the channel of the port goes into box(i still need to know this....would this be considered the volume of the port?)....also, I know different subs recommend different shaped ports, anyone know the recommended port for the ssd18? circle/square/slotted/etc.

[Julian 641]

Thanks for the calculations Julian, but let me be a tad more specific. Port opening size = square inches(i now know the required size, ty)....port depth = how far the channel of the port goes into box(i still need to know this....would this be considered the volume of the port?)....also, I know different subs recommend different shaped ports, anyone know the recommended port for the ssd18? circle/square/slotted/etc.

It doesn't matter how it's shaped, it could be triangle, octagonal, or a square. What matters if it has enough port area, the reason port area is such a big deal is because if you don't have enough you're basically either running a leaking sealed box or you will have terrible port noise (Like schuffing sounds)

[Duran 387]

You will have to get in contact with Nick or Scott to get xmech figures, they aren't posted.

As far as ports, whatever gets you sufficient cross sectional area will work great.

[emh9009 199]

I don't see why you need to know how far the cone can travel, when you know it will be distorting and your customers will turn tail and not purchase your business if they hear that..

It's not just money that changes how loud you can get. People can do amazing things with the equipment they have, it's really going to depend on the install, their overall goals and how extreme they want to get with their car.

[Duran 387]

Xmech is a useful figure to know sometimes.

[mr mikey 0]

I don't see why you need to know how far the cone can travel, when you know it will be distorting and your customers will turn tail and not purchase your business if they hear that..

It's not just money that changes how loud you can get. People can do amazing things with the equipment they have, it's really going to depend on the install, their overall goals and how extreme they want to get with their car.

Most of the people in the local economy don't care about distortion, they just want decibels(or massive BOOM as they call it). But to be honest, it won't be distorted 100% of the time, but I wanted to make sure that when it did distort, it didn't crash during the distortion phaze. Like when a bit of dirty bass is fed into it during one of the many crappy rap songs that I'm sure will be asked to be played to demo them. I have a sound room, but alot of people are let down after they realize "that room was alot louder than my car!!!" So I got a few old clunkers and shot 'em with a paint gun and put them inside the shop to show off sound systems. Tried to get 1 of each cab style: hatchback, single cab, ext cab(personal vehicle), sedan, & suv. Then one weekend a month, I have certain systems demo'd in each of the cars to show the difference in audible sounds and also in the 'felt' sounds so people will be able to get an idea of how their vehicle will sound. I know that's going the extra mile, but I actually hate for people not to be completely satisfied. Leaving with a smile is much better than a :S face....more times than not, they've returned with friends. ^.^

[mr mikey 0]

Sorry, I totally went off-topic on that one. I do agree heavily with your 2nd part, my younger days consisted of sheets of plywood glued together for flex resistance and 1"x1" boards for corner braces....of course, those were the days of the externally shafted Strokers and stuff. Those were the good ole days.

[Duran 387]

Sorry, I totally went off-topic on that one. I do agree heavily with your 2nd part, my younger days consisted of sheets of plywood glued together for flex resistance and 1"x1" boards for corner braces....of course, those were the days of the externally shafted Strokers and stuff. Those were the good ole days.

[s_carter 5]

I have pushed my SSD18's to over 3 inches of excursion with no problems. I have been told by a few people that the xmech on the SSD18 is about 3.25 inches peak to peak. But it is enclosure and tuning specific. Different frequencies put varying amounts of stress on a woofer, so reaching xmech at 40 hertz is a much different monster than reaching xmech at 10 hertz.

[Duran 387]

Xmech is a killer... you don't wanna smack coils.

[s_carter 5]

I was given an old DHD 12" at one point that was rated for 1200 watts, I ran a 1000 watts RMS to it for 6 months, bottoming it out on a daily basis, before the VC former broke into 3 pieces and separated from the cone. That thing took a lot of torture!

Aren't SSD's suspension limited so that the soft parts will give out before the coils do?

[ssh 924]

Sounds like you like to push your equipment to the limit...

[Tirefryr 1,742]

I have pushed my SSD18's to over 3 inches of excursion with no problems. I have been told by a few people that the xmech on the SSD18 is about 3.25 inches peak to peak. But it is enclosure and tuning specific. Different frequencies put varying amounts of stress on a woofer, so reaching xmech at 40 hertz is a much different monster than reaching xmech at 10 hertz.

Just wondering how you measured this?

[s_carter 5]

Its all about resonant frequencies, I haven't measured it personally, but I have read a lot of material explaining about it.

And yes, I do like to push my gear to its limits, just to see what its capable of. I'm crazy like that.

[Tirefryr 1,742]

I have pushed my SSD18's to over 3 inches of excursion with no problems. I have been told by a few people that the xmech on the SSD18 is about 3.25 inches peak to peak. But it is enclosure and tuning specific. Different frequencies put varying amounts of stress on a woofer, so reaching xmech at 40 hertz is a much different monster than reaching xmech at 10 hertz.

Its all about resonant frequencies, I haven't measured it personally, but I have read a lot of material explaining about it.And yes, I do like to push my gear to its limits, just to see what its capable of. I'm crazy like that.

You stated you've pushed it to over 3", but you haven't measured it, so how do you know you pushed it over 3"?

[s_carter 5]

If you don't believe me, then come demo them, and that speaks for itself.

[Tirefryr 1,742]

I'm very familiar with them and their capabilities. That was not the question. I questioned on how you measured them since you said you did, but now you're saying you didn't, so I just want to know what the truth is.