HSU Project (1 Viewer)

[Jason_Jo]

I have started a new subwoofer project. I have decided on using the HSU driver because I do not like how Shiva's make that loud Popping sound when bottoming out and HSU's in my experience do not make that type of loud startling noise when they bottom out. Anyway I was thinking of making a sealed design. Has anyone here ever constructed a sealed HSU subwoofer? If so how do you like it? How well does it perform in the low end? I was planning on using several drivers. Also does anyone out there know how to calculate the total Q of a sub given a box size? Also with a VAS of 140, does anyone know the optimal box size for this driver, or how I can find out?Programs like WINISD do not seem to be accurate in calculating SPL loss in sealed boxes from my experience.
Thank you in advance for your responses. Also any further suggestions would be appreciated.

 

[Seungsoo Hwang]

Heh I just find it kinda funny you are selecting drivers based upon how they sound when they bottom out! Perhaps you should be looking at designs or limiters of sorts to prevent that? I dont think the HSU driver is superior to the Shiva from my knowledge.

 

[Jack Gilvey]

The Hsu has less Xmax than the Shiva, and would bottom first. Of course, if you plan on bottoming any driver regularly, you won't have it long.

 

[Jason_Jo]

Im not really choosing the HSU on the sole reason that they dont make a pop when they bottom out. But thats a big part. I have made several Shiva Sonosubs, and I just hate that scary feeling you get when your watching a movie and you know a very loud part is coming up and you wonder if its going to pop it. I know that the HSU will still bottom out, but it wont make that loud noise.
I also prefer the sound quality of the HSU a little bit over the Shiva music wise. I've compared the sonosubs ive made to the HSU sub, and the HSU seems to sound better. (in my opinion). This could be due to bad box design on my part, but that is why I wondered if anyone knows how to calculate Q of a driver given the box size and driver specs.
I would like to compare the total Q of the Shiva and HSU. Since (correct me if Im wrong, which I may very well be) Q seems to be an important factor in the actual sound quality of the sub (what some refer to as quickness etc..).
Also the VAS of the HSU is smaller than the Shiva which would make the box size requirements smaller.

 

[Julian Data]

Jason:
The function of the bottoming out and popping noises are derived from several things:

• Amplifier is clipping.
• Leak in enclosure.
• Over driving the driver past it's thermal power limits. Bottoming out the driver thus catapulting the VC through the cone, ripped surrounds.. etc.
• Misalignment alignment of the subwoofer system.

All drivers can pop and bottom out regardless of the manufacturer, unless, there is a limiting system in the subwoofer.
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[Jack Gilvey]

Do you mean the Qts of the drivers, or the Qtc of the final sub? Both drivers can be put into boxes to achieve the same Qtc, but the Shiva will handle more power and have more output. The Qtc will be the primary determinant of the "sound" of your sub.
As far as I know, WinISD will correctly report Qtc, but doesn't take stuffing into account. Try this one:
http://www.danbbs.dk/~ko/ubmodel.htm
It's more complete.