Based on these diagrams, which sub would you build? (1 Viewer)

[Jeffrey_S]

Hi all,
As a follow-up to my last thread, I’m down to the following choice. Should I make the following:

My only hesitation with this beast is that it will stand about 83” tall. The following is a cost estimation:
2 Tempest drivers$300
HS500 Amp$500
BFD$130
Sonotube$ 75
MDF$ 30
Baltic Birch$ 20
Misc.$ 20
Total: $ 1,075.00
I could probably find a cheaper alternative for the amp.
Or should I make this:

The following is the cost estimation for this sub:
One Blueprint 1803 driver$280
QSC RMX 1450 amp$400
BFD$130
Sonotube$ 55
MDF$ 30
Baltic Birch$ 20
Misc.$ 20
Total: $ 935.00
I’m going to need a BFD either way due to room considerations. So I guess from a cost analysis, the price for each sub is similar enough. Of course, from what I’ve heard, I might have to live with fan noise with a QSC amp.
This sub will be used for about 70% hometheater / 30% music. I am mostly concerned with hometheater sonic punch.
So what do you guys think? Which one would you build and why? What amp would you use?
Thanks again to everyone!

 

[Achim Eilers]

Hi Jeffrey,

I just finished a 24" Sonotube 78" tall with feet, tuned to 18Hz designed for an 1803(which I hopefully receive soon).

For now i made an adapter to fit a 1503. The output is quiet scary all the way down to 15Hz with BFD,its powered by a BRYSTON 4B in bridged mode(I hate fan noise). As a little gag I put 3 Halogen lights on the top using a remote switch.

Achim.

 

[Jeffrey_S]

Got a reply from Dan Wiggins regarding stuffing for the dual Tempest sub. Mike Strassburg if you're listening I know you were curious about this as well.

"Stuffing? I'd use comforter batting (a sheet, about 1" thick, of polyester

batting used for lining quilts and comforters.). It's available at most

fabric stores. I'd look to use about 12 pounds of it, and line the walls

with it. A bit of glue, or just a few staples will hold it up fine. And

the sheet format makes lining the walls VERY easy."

Jeff

 

[Mike Strassburg]

Jeffrey,

THANKS for the update! Looks like I'll have to add that to my list....Mike

 

[Mike Strassburg]

Jeffrey,

Was just looking at my e-mail from Dan and here's what he suggested: " As far as polyfill, I'd stuff 8 pounds of

polyfill in the cabinet; no need to line the walls, just stuff the polyfill in the tube."

Are you a little confused? I am! 8#'s to 12#'s is a 50% increase, so I'm sure that will affect the sub, but I'm not sure how. Also not sure why he now recommends the batting to polyfill, perhaps just for ease of installation.

Have you decided on a design yet? Will the 1450 be enough to drive the 1803, seems like you'd need more power to really push it as the Blueprint site talks about feeding it 1000watts. I'm sure EITHER sub will be awesome.

I'm still going with the dual Tempests, but didn't figure in the cost of a BFD as most say they're not necessary. Also I'm choosing to use the HS500 although there are several less expensive amps that would drive this sub.

 

[Jeffrey_S]

Mike,

I'm really confused now too! When I e-mailed Dan, I asked if he recommended stuffing and how to use it. I told him I was concerned with it interfering with the movement of the bottom Tempest. Maybe that's why he recommended lining the walls. That doesn't explain the difference in total weight, however. To add to the confusion, I know that some on this forum say stuffing isn't needed at all. In this case, it could be to safeguard against standing waves since we are dealing with a 69" enclosure. I guess another e-mail to Dan is in order to clarify the situation further.

I'm pretty sure I'm going with the dual Tempest sub. I e-mailed Pat at Blueprint for his recommendations in making the 1803 sub shown above. In those recommendations he recommeded a x-over frequency of 60Hz. I think the Tempest's would have more range than that.

I think I'm going to go with a 28" sonotube. This will allow reducing the tube height from 72" to 53". I found a local supplier that stocks it. Also, I'm pretty sure I'll also go with the HS500. It is kind of pricy though.

Jeff

 

[Jack Gilvey]

I'm still going with the dual Tempests, but didn't figure in the cost of a BFD as most say they're not necessary.

A good parametric eq like the BFD should be considered essential for good sub performance, not so much to address shortcomings of the sub but, rather, those of the room. The 1803, and other high-excursion drivers, tends to exhibit an inductance peak around 70-80Hz which makes it mandatory with them.
I wouldn't put the time and money into a DIY sub project just to save $130 on the eq .

 

[Pete Mazz]

Doesn't the Adire amp have some EQ function built in?

Pete

 

[Jack Gilvey]

It's got a 6db boost-only, fixed at 1/2 octave, 20-50Hz. Apparently meant to counteract a premature rolloff rather than help even out a room response.

 

[Mike Strassburg]

Jeffrey,

So by going with a 28" tube you can shorten the height to 53", and the port size/lenght stay the same?? I'm assuming that the 28" x 53" gives the same internal volume as the 24" x 72". I may also build this one as I could totally hide it behind my TV.

Jack's point about measuring door openings is WELL TAKEN!!

 

[Jeffrey_S]

Mike,

My door openings are about 30". So if I make the plates external to the sonotube 29 1/4", I think this will give a good result. Yes, I calculated that the internal volume stays the same. I'm pretty sure that this is the way I'm going to go. The only dilema left is a final decision about the amp. The HS500 is pretty pricey. I'd like to find an alternative if one exists.

Jeff

 

[Mike Strassburg]

I would think the QSC-850 would be a good choice. Do a search on it. They're under $300 new and perhaps cheaper on e-bay.

I'm going to measure my door openings and behind the TV to see how a 30" sub would look/fit.

Main reason I'm considering going bigger but shorter is that I haven't found any fabric to fit one that's 72" tall. Take care...Mike

 

[ThomasW]

Check cloth/fabric stores for 'ribbed stockenette'(or something similar). It's a seamless double knit elastic fabric tube that can be obtained on very long lengths.

 

[Mike Strassburg]

ThomasW,

I've tried 2 local fabric stores and longest width is 66", can that be stretched to go around a 24" tube? 24" x 3.14 = 75.36"....if so than it won't be a problem.

Although I have been considering some of the faux grained leather fabrics and they definitely won't stretch.

Gotta measure those door openings tonight and cut out a 30" cardboard cirle to see just how big that really is....Mike