bnevets27

iTrader: (1)

I'll be honest, I don't have a clue about car audio. I tried to compare specs but I'm lost. I made a comparison chart of a bunch of slim subs. I'm looking for advice on them.

From what I can gather people love the Stereo Integrity BM mk3’s but I’m not prepared to spend that much, and you can’t buy it at the moment.

Here's the chart:
https://sheets.google.com/pub?...=0&output=html

One spec I'm curious about is Xmax, I basically understand what it is but it can vary from 4mm - 14mm

Not exactly sure the cubic feet I have to work with at the moment, hoping to get 1cu.ft. A little more FYI, sub will be going behind the passenger in a small car (fiero) and I listen to rock.

Thanks

Lord Huggington

iTrader: (1)

Check out Cerwin Vega shallows in 10's & 12's... or atleast I think they've got 'em? Can't remember.

Xmax varies between each sub, and it doesn't just range from 4-14mm. It can be whatever it's designed to be (crazy prototypes move a few FEET), it's not a scientific constant. Xmax is the maximum linear travel of the voice coil/cone before it leaves the magnetic gap, not to be confused with XMECH (the full mechanical length that it can move). I think most brands rate xmax as the driver retaining up to 70% linearity. For instance if a sub has 15mm xmax than the motor is at 70% linearity when travelling the full 15mm. When a motor loses linearity it causes distortion, which is a speaker killer. Therefore the more a speaker moves the worse the sound quality will be. Some speakers have close to zero distortion because they retain very high linearity and stay that way throughout movement, but this comes at a compromise to output. Xmax really doesn't matter unless a speaker has so many compromises that lots of xmax is the only way that it can perform as intended.

You have the option to use different types of enclosures, but a sealed box would be best for your application.

Are you considering a shallow because they're cheaper, want to save space or because you want to hide it conveniently? They won't always have the greatest in-vehicle response because of the specs, and there's better speakers that aren't shallow (+3" depth over a shallow) that would sound a lot better in a 1 cubic foot sealed box. You could use a sealed fiberglass enclosure on the side of the trunk (trunk?), so it'd be out of the way.

bnevets27

iTrader: (1)

This is where I plan to put it. I only plan on doing one, It should be sufficient, if not I can always add another.


I had planned to make it sealed. From another persons dimensions it looks like I probably wont get any more then .65 cu. ft. Their box had a depth of 3.5' (not the same as the above picture)

So I'm looking at shallows because the need for small box size/small cu. ft. and limited mounting depth.

I looked at the Cerwin Vega shallows. They only have a 12', and it's suggested box is 0.75cu.ft. It's magnet also sticks out from the front of the sub. They actually look a lot like the older MB Quarts. So it doesn't look like they will work. They look nice though. I can't find a price or anyone that sells them.



Ok, I understand Xmax a bit better now. I meant it can range from sub to sub. Seeing some subs with a spec of 4mm and some with a spec of 14mm. To me Xmax equates to air movement, the higher the Xmax the more air is moved therefore louder. So what I gathered from what you said is:
A sub will sound better if it doesn't have to move the cone/coil as far.
A sub will sound good as long as it stays as linear as possible, any movement side to side will cause distortion.
A sub with a larger Xmas is compensating because it has a lower output?
So what does this mean when comparing subs? Stereo Integrity BM mk3’s has an Xmax of 14mm and its (from what I gather) considered a good sub. So I'm assuming Xmax is just another spec that has to be compared relative to the rest of the sub specs. Other words long Xmax doesn't = good, short Xmax doesn't = bad.


I guess I should also mention what I'm going for. I'm not going for all out loud. I actually rather quality. But at the same time I'm no audiophile.

I figure I should also mention what the rest of my system consists of.

MB Quart Discus 5.25 Component - Front
Power Handling: 35 - 90w (told they do well at 100w)

Infinity Reference 4" x 6" two-way plate - Rear
RMS-45w
Peak-135w

Tang Band 5.25 Subwoofer - In stock location under dash (Think I killed it)
RMS-40w
Peak-80w

Amp:
MTX Thunder X - 704X
70 Watts RMS x 4 Channels at 4 Ohms
210 Watts RMS x 2 Channels bridged

Running my fronts off the amp, the rear's off the deck. The 5.25 sub is running 2 channels bridged off the amp.

I'm actually looking for advice on how to properly balance the system with the new sub. Maybe need to get a different amp...? I also planed on keeping my existing sub and use it as kind of a mid bass. Does that work/make sense?

BigRedGuy

iTrader: (11)

I'll wave the flag for the Kenwood Excelon shallows....the manual for the 12" and 10" drivers is here and the 10" is good in .6cuft sealed or ported. There is an 8" version as well which may fit better in the space you have.

If the TB is not dead you could use it as a midbass.....I prefer midbass drivers in stereo but it could reinforce your comps without throwing off the front stage image if it's under the dash.....
The other problem is creating the xover bandpass to power it with the right frequencies....It's tough to do without buying another amp and by the time you do all that you could put a 6.5" comp set up front....

I would try a single 10" ported running off the rear channels of your amp first....with the fronts amped and the rears off the deck that may be enough. You will need to tweak the Xover settings to bring the sub up a little more than usual to help the bottom end of the comps. I generally keep 5.25" speakers over 100hz to keep them from complaining too much when they are getting real amp power....

HTH

bnevets27

iTrader: (1)

Well if the TB can be useful and it is dead I can just get another, they are cheap. Just as long as it will actually contribute to the system. I'm not sure if it would get washed out considering it doesn't take much power?

The TB is under the dash, here's a pic, the dash would be over top of it. Its in a ported box and has a tube off the top (not in that pic).



If I end up running my fronts and sub off my amp then I would need to get another amp anyhow. Unfortunately this car doesn't give me the ability to put 6.5's up front here's just no room. Original it actually came with 4x10's So the 5.25 components where a nice upgrade.

I'm curious to why you suggested a ported box? I was thinking about doing it sealed and, of the installs I have seen, none have been ported. I honestly don't know why. Good to hear that I might be able to get away with the amp I have to power the sub.

Thanks for the advice, that helps me out a lot!

EDIT: I read the kenwood manual and I assume you told to try ported because the kenwood has better output ported...

Lord Huggington

iTrader: (1)

A ported 10" could outperform two sealed... not to mention it's cheaper. You atleast get to tune it for the best response. If you're going for strictly SQ with rock only than try ported @ 40 Hz first. Those shallows might even model all weird in a sealed box. To model them you need the QTS, f/s, and VAS (in cubic feet):

Sealed Subwoofer Speaker BOX DESIGN - Qtc Calculator

Taco

I aswell will back the Excelon shallow woofers, worked with quite a few when they first came out. Surprised me when I first heard one, and I actually still have one Brand new in the box never been opened....

coolmen

Nobody have try AB slim sub ?

bnevets27

iTrader: (1)

So I did a mock up out of cardboard, which has been quite helpful. Looks like I'm going to have a little issue with space behind the sub.

I've read that I need to have enough space behind the sub to allow proper cooling of the voice coil. Looks like the recommendation is to have somewhere between 1.5 - 3 inches of space. Would I be able to get away with 3/4 - 1 inch?

I have 4 inches from the face to the back of the box. I don't want to increase that because I'll loose leg room and the box doesn't need to be any bigger.

If I can't get away with only 1 inch behind the sub then I might have to go with a sub that isn't vented in the back. I have a little chart with which sub should work well with a ~0.65 cu. ft. box.

I figured if the sub didn't have a hole in the back then it isn't vented out the back. So looks like the only ones that I know of is the Dayton and MTX.

Here's the chart:


Spec Sheets:
Kenwood
Dayton
Elemental Design
MB Quart
MTX

One last question, if I was to put the kenwood in a vented box, as suggested. The spec sheet says to use a 3in x 11in tube. Would two 1.5in x 11in be the same?

I'll post a pic of the mock up or a CAD drawing, so you can see what I'm working with.

Dilatory

iTrader: (1)

If you were to glue a thin layer of sheet metal to the back of the box to act as a sort of heatsink that would probably solve your venting issue.

Just make sure to go about it properly so that it doesn't rattle loose or what have you.