Hey Tom V., have you heard/done anything with this driver? (1 Viewer)

[TerryC]

Josh,
It still works, just click on the actual measurement. An example in the VAS field, it will say "l"/"ft-3"/"m-3"/"in-3" just click on that "fill in the blank" and it will change to the next one.
Hope that helps?
Terry

 

[Chris Hoppe]

There is no reason you can't use ports with the HE15's! The advantage of the PR's is that they are basically equivalent to very very long ports, which is what's needed to use a small box.
If you want to do a large sonotube where the port lengths are reasonable, then you SHOULD use ports, as they will actually perform better in this case.

 

[John E Janowitz]

Josh,
The HE15's have a fairly high Mms, around 260grams. This is not suggested for downfiring as the effects of gravity will sag the driver over time.
With regards to the HE15 and PR's, in the 22" cube that we suggest, you would need a minimum 6" diameter port, 58" long. In a situation like this you will get very high amounts of compression in the port since the length is almost 10 times the diameter.
The HE15 is not suggested for very large enclosures due to it's stiff suspension and resultantly small Vas. I would not suggest anymore than a 7 cubic foot enclosure for the HE15. Even in that size you will have a large peak in output at Fb, and a dip in response above Fb. In 7 cubic feet, you'd still need a 6" port nearly 27" long to get an 18Hz Fb.
The advantage of the PR's is to get the lower tuning in a smaller enclosure. They will also eliminate most of the problems with compression in the port, vent noise and pipe resonances. In the case of two 15" PR's you get the equivalent of an 18" diameter port 230" long.
John

 

[Josh Davidson]

How much output is added by using PRs or is it an exact substitute for the port sizes you listed?

 

[John E Janowitz]

Well, the PR's a guess could be said to be an exact substitute for the 18" diamter 230" long port. The don't necessarily add any output, but having the PR's you will get much less compression as your output levels increase. So I guess in that manner you could say that you gain some output, but really you just don't lose as much output as you would with port compression.
John

 

[Josh Davidson]

One more thing, why do you guys recommend a cube? I've always been under the impression that perfect cubes should be avoided when creating enclosures.

 

[John E Janowitz]

I guess there is no particular reason for the cube other than it is the most compact shape, and it allows for adequate clearance for the woofer and PR's inside the enclosure. For subwoofers the enclosure shape is really not all that significant. In a fullrange system you would not want a cube as you can have more problems with standing waves when all dimensions inside the box are equal. In a subwoofer the wavelength of your frequencies will be much greater than the internal dimensions in the box, so this will not be a problem.
A cube is also a little easier to built IMO.
John

 

[Magnus Lindqvist]

John, is the HE15 still available? if it is what does it cost??
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/Magnus Lindqvist.
The "Finish Fetish" guy!

 

[John E Janowitz]

Hi,
The HE15 woofers individually were a one time deal I put together. I can still sell them individually, but I need to price them at $800 to keep the manufacturer, and the big car audio companies happy. I can offer a rather significant discount on the entire kit with the woofer, 3 PR's and MDF box kit for $1000 instead of $1195. This allows you to build the same subwoofer as our production Thunder15 that will be selling for $3000.
In the future if I can pull together another 50 driver preorder I may be able to offer the discount again.
John