Manufacturers sealed enclosure specs

[psycho72 10+ year member]

Everywhere you guys have info on ported but nothing on sealed. How can you figure out what the best size box is for a woofer when the manu spec says .75-1.5. Does that mean that it performs at it's best at anything between that or is one of those a sweet spot. Can the t/s perameters shed any light? Does it matter? What affect do the sizes make?

And I did a search, I even read like 10 posts that did'nt help at all.

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[DFW40 10+ year member]

It depends on what car you are driving and what sounds good to you. The bigger box of 1.5 will offer a lower Qtc which is a flatter smoother overall response and a little more output on the low end and the smaller box will do the opposite. It will give you a tighter punchier bass but you lose a little on the low end. I have always like the larger box sound personally. I'd go with 1.25 in your case. You can calculate this and that but it all comes down to what sounds good to you. Some songs would sound better on the smaller box and others would sound better on the bigger box. There is no perfect box for every song or music.

 

[chevy6998 10+ year member]

Everywhere you guys have info on ported but nothing on sealed. How can you figure out what the best size box is for a woofer when the manu spec says .75-1.5. Does that mean that it performs at it's best at anything between that or is one of those a sweet spot. Can the t/s perameters shed any light? Does it matter? What affect do the sizes make?
And I did a search, I even read like 10 posts that did'nt help at all.

I ran two 10" subs in 1.0 cu ft boxes and that seem to do best in a truck application, simply because the cab is smaller than a car cavity and the subs are right under you ass pratically, I would be willing to bet that in a car a ported enclosure would do better that a sealed because it can project stronger with more spl, ex: those two 10"s are in my honda and dont hit near as hard even with the seat down, cuz the cavity is much bigger now. I prefer sealed 1.0 cube boxes overall in my experince because you can get more "precision" bass (I listen to alot of metal) but still get about 70% of the bass reponse that a ported enclosure gets for rap and other heavy bass tunes. I think its good mix. My truck project im installing (4) 10"s in a single cab all sealed with about 500w per sub, well see what happens!

 

[squeak9798 5,000+ posts]

Does that mean that it performs at it's best at anything between that or is one of those a sweet spot.

All depends on the listener's personal preference. Typically, manufacturer's will recommended boxes on the smaller side (higher Qtc) because it gives a nice bump in the output in the upper bass/lower midbass region, which is what gives subs a "tight" or "punchy" sound. Plus, that hump in output works out nice for the rap/r&b crowd, which are the main purchasers of subs.

Can the t/s perameters shed any light?

Exactly //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif That's typically how proper box sizes are determined.

Does it matter?

Yes, each box size will have a different effect on sound.

What affect do the sizes make?

As mentioned, larger boxes have a lower Qtc, which means it will have a flatter response, better low frequency extension, higher efficiency (less mechanical power handling) and better transient response and group delay. Smaller boxes have a higher Qtc, which has a hump in the response (again, in the lower midbass/upper bass area) and more overall output, but less efficiency (higher mechanical power handling), less low frequency extension and worse transient response and group delay than the larger boxes (lower Qtc boxes).

Qtc is a measure of the response and resonance of the "system" (the sub in the box). It "tells" you what box size will have certain affects on the sub and the subs output. For example, a box with a Qtc of .707 will have maximally flat frequency response and the lowest F3 (basically, best low frequency extension) of all the boxes with a transient response and group delay that are "acceptable". A box with a Qtc of .5 has optimal transient response. A box with a Qtc of .577 has maximum group delay. But the .5 and .577 will have a lot less output.

And it's the T/S parameters we use to determine the box size and Qtc that the box size gives us. That's how box programs work. But, it doesn't work in every situation.....take, for example, the 12" RL-p that I have coming to me. When you load it up into a box program (winISD, etc) or into a Qtc calculator....the results are just weird. It's like it specs out as a midbass rather than a sub (for a Qtc of .707, it gave me a box size of .219cuft with an F3 of like 101hz). But, in the real world the sub works just fine in boxes .75 - 1.5cuft

 

[Nikuk 5,000+ posts]

I didnt read all of that techno-babble but Squeak is usually right (although Long-winded). Except when it comes to getting loud... //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[squeak9798 5,000+ posts]

Except when it comes to getting loud... //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

That one cut me deep man...that one cut me deep......

 

[Nikuk 5,000+ posts]

That one cut me deep man...that one cut me deep......

Time heals all wound boyee.

 

[squeak9798 5,000+ posts]

Time heals all wounds

//content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif You have flowers on your curtains, don't you?

 

[Nikuk 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif You have flowers on your curtains, don't you?

ummm, no.

Do you have them on your panties?

//content.invisioncic.com/y282845/emoticons/omg.gif.05aa02c3095d6ce9338996654eca0863.gif

N00B.

 

[psycho72 10+ year member]

take, for example, the 12" RL-p.....sub works just fine in boxes .75 - 1.5cuft

Hey how did you know I was talking about the 12" RL-p???? I am thinking of getting two. Maybe even 15's, but I am not sure just yet which ones.

Now, for my wrench, how about if I were to run 2 woofers, each one off on its own channel (or 2 seperate amps-and this is just a hypothetical because I don't have the cash just this minute), one woofer in a .707 box and the other in a .5 box, would that give me the best of both worlds? Or would the two woofers behaving differently cause problems in the overall sound?

 

[squeak9798 5,000+ posts]

Hey how did you know I was talking about the 12" RL-p???? I am thinking of getting two. Maybe even 15's, but I am not sure just yet which ones.

I didn't....LOL. But I just bought one (should be here tommorrow) and I was screwing around with it in box programs.....just wasn't workin' (as I mentioned) //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Now, for my wrench, how about if I were to run 2 woofers, each one off on its own channel (or 2 seperate amps-and this is just a hypothetical because I don't have the cash just this minute), one woofer in a .707 box and the other in a .5 box, would that give me the best of both worlds? Or would the two woofers behaving differently cause problems in the overall sound?

The bold wording is the answer to your question //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif