1. ## Help to find out tuning freq for 2 subs

Hello,

Some months ago I made box for ONE (1) Type R subwoofer.
Net Volume: 3cu.ft
Tuning Freq: 30Hz
Port Width: 3.25 inch
Port Area: 40.625 square inch
Port Length: 35.25 inch
http://i47.photobucket.com/albums/f2...ll/boxdims.jpg

Now I want to put TWO (2) Type R subwoofers to same box.

So how can I calculate what will be tuning freq with two Type R's in this box?
Port width, area, length will be same.

It would be great if you could explain how to calculate that tuning freq

Thanks.

2. ## Re: Help to find out tuning freq for 2 subs

2.0-2.5 per 12 @ 33hz would be good...

3. ## Re: Help to find out tuning freq for 2 subs

so you want to put 2 type-r's in the same box that you had one type-r in?

So basically the only thing that would be different is the .071 displacement of the second sub.

Comes out to [email protected] Your initial calculations were a little off or something.

4. ## Re: Help to find out tuning freq for 2 subs

2.8 @ 31hz.

The enclosure's tuning frequency is based on the port area, length, and net volume. The only thing that changes when you add the second sub is the net volume and by a very small amount.

That enclosure is probably going to lose a little bit of low end and get peaky around 40hz with two subs in it.

5. ## Re: Help to find out tuning freq for 2 subs

The minor displacement of the subwoofer added to the enclosure isn't going to effect the port tuning to any great degree that you would notice it.

6. ## Re: Help to find out tuning freq for 2 subs

you will notice that the box lacks the low end it once had though... new box time

7. ## Re: Help to find out tuning freq for 2 subs

Originally Posted by profundus-sanus
so you want to put 2 type-r's in the same box that you had one type-r in?

So basically the only thing that would be different is the .071 displacement of the second sub.

Comes out to [email protected] Your initial calculations were a little off or something.

Yes I want to put 2 Type r's 12" to same box.

8. ## Re: Help to find out tuning freq for 2 subs

Originally Posted by Decipha
you will notice that the box lacks the low end it once had though... new box time
WHAT!!!! That's a load of nonsense.

He'll still have the low end he had before, the addition of the second subwoofer ain't changing the port tuning to any great difference of increase.

Add the second subwoofer and see how it sounds, then decide for yourself if building a new enclosure is worth the effort, just don't go building a new enclosure thinking that it's going to change any of the bass/performance response from what you have presently.

9. ## Re: Help to find out tuning freq for 2 subs

mainly because now two subs are sharing the "3" cubes instead of one in three cubes. take 1 sub in three cubes and one in 1.5 and see how different they sound. i'm not saying it will lose or gain anything, just that it might sound different and you might not like it. or on the other hand you might love it. personally i would build a new box.

10. ## Re: Help to find out tuning freq for 2 subs

Originally Posted by almond
mainly because now two subs are sharing the "3" cubes instead of one in three cubes. take 1 sub in three cubes and one in 1.5 and see how different they sound. i'm not saying it will lose or gain anything, just that it might sound different and you might not like it. or on the other hand you might love it. personally i would build a new box.
OK, in that I would agree 100% given the volume is now split for two sub's and the output is definitely going to increase along with the F3 of the sub/enclosure.

11. ## Re: Help to find out tuning freq for 2 subs

Originally Posted by Decipha
you will notice that the box lacks the low end it once had though... new box time
Well I could agree with you. I will lose low notes. So this mean that box will be tuned higher. This is what I'm seeking. I want to make SPL box
It was SQ box because was tuned low and was playing low notes. And if I put second subwoofer I will lose low notes. If I lose low notes it will mean that box tuned higher. Agree?

But I don't believe that tuning freq will increase only to 31Hz...

Are you guys sure that only subwoofer dispacement will affect tuning freq?

12. ## Re: Help to find out tuning freq for 2 subs

Originally Posted by Beginer
Well I could agree with you. I will lose low notes. So this mean that box will be tuned higher. This is what I'm seeking. I want to make SPL box
It was SQ box because was tuned low and was playing low notes. And if I put second subwoofer I will lose low notes. If I lose low notes it will mean that box tuned higher. Agree?

But I don't believe that tuning freq will increase only to 31Hz...

Are you guys sure that only subwoofer dispacement will affect tuning freq?
The port tuning is effected by the Net Volume, Sub Displacement, Port Size and Length, plus any other displacements = Port Tuning.

Change any of these and your port tuning changes, by how much depends on which program you used to design the enclosure to get the spec's.

13. ## Re: Help to find out tuning freq for 2 subs

your tuning will still stay the same, but your frequency response will change. 3 cubes at 30 hz will have a different responce than 1.5 cubes at 30hz. it depends on the sub. try playing with winisd to see how the different volumes affect the response curve.

14. ## Re: Help to find out tuning freq for 2 subs

the box won't be tuned higher but it will probably peak higher because of the smaller port gain(which is centered at tuning frequency) of 1.5 per sub instead of 3 per sub.

You probably will lose some low end, but you'll also probably get a flatter response than before as well.

15. ## Re: Help to find out tuning freq for 2 subs

Yeah, but he's not going to lose enough low end that he'll notice it and as for a slight high peak, of course he's going to get a dB gain just by adding a second sub.

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