speakers in box, losing loudness?

[Imshirazy 10+ year member]

Hey guys, I just recently thought up a possibility. I have two alpine type R 6.5s in a small box, maybe 7x7x7, possibly a bit bigger. Anyways, the speakers are on opposite sides and both playing in same polarity (box is also sealed). I was wondering whether or not this is creating more of a struggle for the speakers or if i am losing any amount of volume due to this.

The reason they are in a box is because this was the only way to wedge it inbetween the center console and the back seat, fits perfectly.

I'm just wondering if there are any bad sides to having speakers boxed,

thanks

-Ivan

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[squeak9798 5,000+ posts]

If the speakers were designed to perform optimally infinite baffle or in larger volume enclosures (such as most car audio oriented mids are) then putting them in a "small" enclosure would decrease their low frequency extension and low frequency output aswell as decrease their sound quality (transient response) in the lower frequencies.

Without knowing the T/S specs of the speakers, it's tough to say to what if any extent you are "impairing" their performance.

 

[xtremekustomz 10+ year member]

I've got a friend that has some sealed in a door panel that have close to the same amout of space you are talking about. He's got 2 in each door and they do very well as a midbass.

 

[Imshirazy 10+ year member]

If the speakers were designed to perform optimally infinite baffle or in larger volume enclosures (such as most car audio oriented mids are) then putting them in a "small" enclosure would decrease their low frequency extension and low frequency output aswell as decrease their sound quality (transient response) in the lower frequencies.
Without knowing the T/S specs of the speakers, it's tough to say to what if any extent you are "impairing" their performance.

My concern isn't so much losing quality because I have the speakers playing mid to high frequency anyway, I only want bass out of my subwoofer. But I thought that with shared air enclosures (for subs at least) that there were like a 3db loss in sound especially in isobaric, which is why I was just wondering if it's the same with this.

 

[Gary S 10+ year member]

For speakers that small, a box will usually simulate infinite baffle... the air space requirements are so small to begin with.

Boxes are the best way to do it.

 

[xtremekustomz 10+ year member]

For speakers that small, a box will usually simulate infinite baffle... the air space requirements are so small to begin with.
Boxes are the best way to do it.

Hmm....how is a small box simulating infinite baffle? IB uses no box at all. Most small car drivers require a large sealed enclosure because they are made for infinite baffle configuration such as a door panel that usually has a good bit of air space. The best way to do it is to call the manufacturer and see what they recommend. I called Alpine a while back and I believe they told me .5 cu ft per 6 1/2". I know that particular driver has been used in much smaller applications though. A good bit smaller. It is only being used from 60-140 hz though so it is only being used as a midbass. Personally...I've always been told to make the enclosures are large and as strong as possible.

 

[genxx 10+ year member]

X2-On the box simulating infinite baffle? If my math is right the boxes you are using are about .19cf not sure what driver displacement would be. Thats a hell of alot less then looking at IB in a door. In theory it works with a large box but this what I can tell you.

Messing around the garage one day I decided to take some 6x8's I had laying around made about 4 different boxes with different cf and they all sounded like arse, even with an amp. It was an experiment because I have about 12 of them laying around and figured if I could get any volume out of them I would throw them in my buddies boat on the cheap for him. So I pulled of a door panel slapped different ones I had in there and there was a night and day difference between the volume and sound.

Which has led me to believe you cannot simulate IB with a sealed enclosure. I am not sure what technically happens. So maybe someone smarty than me can chime in.

If you had the specs on these I would be than happy to plug them into unibox and see what it looks like.

 

[Gary S 10+ year member]

Hmm....how is a small box simulating infinite baffle? IB uses no box at all.

- What is a small? A box can simulate infinite baffle... depending on the particular driver, you can build a box for an infinite baffle driver big enough so that there is no noticeable difference between true infinite baffle and the sealed box. And if the speaker is smaller, the box size can often be dramatically smaller. Don't get hung up in absolutes.

 

[xtremekustomz 10+ year member]

- What is a small? A box can simulate infinite baffle... depending on the particular driver, you can build a box for an infinite baffle driver big enough so that there is no noticeable difference between true infinite baffle and the sealed box. And if the speaker is smaller, the box size can often be dramatically smaller. Don't get hung up in absolutes.

I agree 100% but an enclosure too small for a 6 1/2" driver will limit it's performance in the midbass region.

 

[genxx 10+ year member]

OK. After doing some research it can be done. Problem is to get it right you need to know the Vas of the speaker. The enclosure would need to be 3 times the Vas depending on the speaker. So if you can get the Vas on those speakers then you can figure out the enclosure size to simulate it. My current recommendation is that your enclosure's are way to small.IMO

Some things say 4 to 10x the Vas but I am no expert on IB so I can debate on what is correct.

Props to Gary S.

Still not sure why you want to do it. An idmax12 would need roughly 20cf sealed to simulate it.

 

[Gary S 10+ year member]

Thank you genxx for looking up the particulars.

I want to add something... realistically, it would give the op better overall sound to have speakers in the doors or kicks, box or no box (if he does not already)... system would have added imaging and a front sound stage. A box between the seats is about as bad as it gets for speaker placement... which is one of the most important things, believe it or not.

Also... depending on how close to the ears those drivers are (sounds like they are at his elbows), and how far apart the drivers are from each other, depending on those ratios... plus, are they firing in opposite directions? Could be getting some kind of bipole/dipole effect and a lot of midbass cancellation. Again, speaker placement is anywhere from bad to very bad.

 

[squeak9798 5,000+ posts]

My concern isn't so much losing quality because I have the speakers playing mid to high frequency anyway, I only want bass out of my subwoofer.

I wasn't referring to "bass".

Just the low frequency response of the speaker, regardless of where that falls within the audio bandwidth. Given these are mids, the enclosure could potentially affect the midbass response of the drivers.

But I thought that with shared air enclosures (for subs at least) that there were like a 3db loss in sound especially in isobaric, which is why I was just wondering if it's the same with this.

A pair of speakers ran isobarically will have 3db less output than a pair of non-isobaric drivers ran off the same power.

But your speakers aren't being ran isobarically, so I'm not sure why you are concerned with this ??

 

[Imshirazy 10+ year member]

Not isobaric I understand, but the fact that they are using the same airspace I figured might do something bad you know?

I understand that the placement is terrible, but there really is nowhere else to place them. I tried looking for areas in the front dash and there's no mounting room anywhere, the side panels have far too many curves and I don't trust my own custom fabrication to mount them there. The only option I really had left was to place them in a box behind the console.

Then when I think about it, im not 100% sure if they are even worth having there solely because of all this mess, especially with a limited box size to work with in order to wedge it in there

what about porting?

This all seems so silly for a pair of 6.5s but it's kind of exciting

and I can't find the VAS for those speakers no matter where i look

maybe im just terrible at looking

 

[Gary S 10+ year member]

I probably should have asked these questions at the top... list your system and your car - is it the system in your sig?

If so, why do you have 3 - stereo pairs of speakers? You really only need one stereo pair up front unless you are running a surround processor. Is this the center channel for a surround system? I see you have a 7-channel amp.

 

[Imshirazy 10+ year member]

7 Channel amplifier but only 2 component sets right now, I removed the 6x9s.

Car is a 2000 honda civic EX, type X speakers are in the front door panels and the type R 6.5s are in the middle wedged into the seats. Tweeters are mounted atop the panel facing my ear about 2 feet away.