Home Theater Forum and Systems banner

1 - 20 of 428 Posts

·
Premium Member
Joined
·
348 Posts
Discussion Starter #1 (Edited)
Okay, I was the guy lucky enough to win this amazing 21in driver from Exodus Audio, so I guess I've got to do something with it. This will be my first speaker build ever...no pressure though:yikes:. This post will be a thought starter as I will need lots of input from those of you more experienced types.

Here's my situation and my thoughts. I don't have a ton of room. I don't have a dedicated HT room. My system is in my main living area. Its 14x20 and vaulted ceiling, open floor plan to kitchen, dining room and foyer. There is currently 2 SVS PB-13 Ultras squeezed in there. Every square inch of wall space is taken up by furniture or stereo equipment. Will this new beast be added to the existing 2, replace them, or end up in the HT of my buddy who already has called dibs? We'll have to wait for the finished product to make that determination.

Aesthetics and WAF play an important part of the project as this is the main part of our house. I don't think I want to go sealed because I assume it would take a very beefy amp to get what this thing is capable of in a sealed box. A ported box presents the problem of size. From the little bit of modelling I've done, I think I need to be near 500L to do this driver justice. That has me leaning toward a Sonotube. The sonosub program says I can mount this driver horizontally, but I guess Kevin can answer that more definitively.

In my modelling I'm making the assumption WinISD doesn't care if the box is a cube or a tube, correct me if I'm wrong. i would like to keep this thing down around 6 feet, so I went with a 480L enclosure. In my limited knowledge that seemed to give me the smallest enclosure without sacraficing too much performance. I use my system for music, gaming and movies but most of the high volume is with music. I love loud music with lots of bass. With that in mind I used a 20hz tuning. A single 8in port would require a 24" tube. Those specs get me in that 6ft high range. I'm modelling with 1500W and an active high pass filter at 17hz. I do use a BFD1124p with my Ultras but don't have any eq factored into the following graphs.

480L sono @ 20hz.JPG

480L sono fr.JPG

I'm starting from scratch here guys and need your input. These are just my initial ideas based on my limited knowledge, so let me have it. The good, the bad and the ugly.
 

·
Registered
Joined
·
3,068 Posts
Re: Maelstrom-21 giveaway build

You lucky man you! Boy are you going to have some fun! :hsd:

Just a thought why would you tune a 21" maesltrom to 20hz. I would want it lower if it was me.

Graham
 

·
Banned
Joined
·
1,074 Posts
Re: Maelstrom-21 giveaway build

AWESOME! Congrats man! Put it in a 4.5 cubic foot sealed box.. do that LT thing... and give us some readings! :D

I'm happy for ya man!
 

·
Premium Member
Joined
·
348 Posts
Discussion Starter #4
Re: Maelstrom-21 giveaway build

You lucky man you! Boy are you going to have some fun! :hsd:

Just a thought why would you tune a 21" maesltrom to 20hz. I would want it lower if it was me.

Graham
With this set up I found that tuning to 15hz, yellow line, I was giving up a lot above 18hz to gain a little below 18hz.

20 vs 15 @ 480L.JPG

But then again, maybe I'm barking up the wrong setup tree.
 

·
Premium Member
Joined
·
348 Posts
Discussion Starter #5
Re: Maelstrom-21 giveaway build

AWESOME! Congrats man! Put it in a 4.5 cubic foot sealed box.. do that LT thing... and give us some readings! :D

I'm happy for ya man!
I can't get this to model well in a sealed box. The yellow line represents a 4.5 cubic foot sealed box vs the ported tube. I might be using the software wrong, but every sealed application I try loses a lot of spl at a very high frequency.

20hz vs sealed.JPG
 

·
Registered
Joined
·
9 Posts
Re: Maelstrom-21 giveaway build

Hi,
I just wanted to throw in a quick opinion:
How about 1000 Liters with a 14.3 Hz tuning using 4 6" ports with a length of 37.7" each?
Paired with a 2kW amp, this would be a really nice sub:whistling:

Greetings
RJdaMoD
 

·
Premium Member
Joined
·
348 Posts
Discussion Starter #8
Re: Maelstrom-21 giveaway build

Hi,
I just wanted to throw in a quick opinion:
How about 1000 Liters with a 14.3 Hz tuning using 4 6" ports with a length of 37.7" each?
Paired with a 2kW amp, this would be a really nice sub:whistling:

Greetings
RJdaMoD
WOW! you just gave me a great idea. See the box in the corner that goes up to the ceiling. Obviously thats the chimney, except I put in a high efficiency furnace last year and I don't use a chimney anymore. If I could take the metal pipe out of there, that is a 1200 litre box.

chimney.jpg
 

·
Banned
Joined
·
1,074 Posts
Re: Maelstrom-21 giveaway build

WOW! you just gave me a great idea. See the box in the corner that goes up to the ceiling. Obviously thats the chimney, except I put in a high efficiency furnace last year and I don't use a chimney anymore. If I could take the metal pipe out of there, that is a 1200 litre box.

View attachment 19181
35.3146667 cubic feet... 42.3776001 cubic feet!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 

·
Registered
Joined
·
9 Posts
Re: Maelstrom-21 giveaway build

If going SLLT, you might also consider a deeper tuning. Try the folllowing in WinISD:
1100 Liters, 11.5 Hz tuning using a 10" port (should be 33.7" long), and a 4th order highpass at 9.6 Hz.
1.1-1.2 kW should be sufficient.
 

·
Registered
Joined
·
9 Posts
Re: Maelstrom-21 giveaway build

In compound with 1" mdf, I would not see any problems.
But I'm no expert on this, though I think that Rodney Alvarez could tell you more if you ask him kindly.
Since h is the only one I know of having build an SLLT (have a look in the members build database), he should have some experience with that.
 

·
Registered
Joined
·
1,362 Posts
Re: Maelstrom-21 giveaway build

To the OP; if you want solid low end extension, go with the 1100 liter box tuned to 11.5hz. 12.50hz would actually be a better tuning though. It would gain you more from 12hz and up.
If you want more above 20hz, I would say build a box 395 liters tuned to 14hz.
It would give you 4dB from 20hz and up as opposed to the lower tuned box. But, with the lower tuning, you would gain 4dB around 12hz or so.
 

·
Registered
Joined
·
2,625 Posts
Re: Maelstrom-21 giveaway build

I think you'd be better with a higher tuning. You give up a lot of headroom for that low tuning.

Sealed can be done, but you will need to get a berhinger feedback destroyer to eq the response you want. I'm not sure aesthetic is happening with a ported monster that size.
 

·
Premium Member
Joined
·
348 Posts
Discussion Starter #16 (Edited)
Re: Maelstrom-21 giveaway build

I do use a behringer right now on my subs. If my room acted like Kevin's simulation in the M-21 application notes, I could probably build a 200L (7cu ft) sealed box and eq it flat out to 15hz. That wouldn't be much bigger than my current PB-13U

You've got me seriously thinking of going sealed now. With the much smaller enclosure I have a lot more ability to play with shapes, finishes, etc and make it a beautiful box. As well, if I sell my existing subs I would have the money to put a lot of power behind the sub.
 

·
Registered
Joined
·
9 Posts
Re: Maelstrom-21 giveaway build

Oh, I'm sorry, I still had the pre-production parameters of the M21 in WinISD.
The actual parameters changed my opinion to 1100 Liters/12.1 Hz with 10" port 30" long (better 11" port 37" long, but I don't know where to get this measure) and approx. 1.3kW.
Tuning to 14Hz might look better in the 20Hz range, but what about room gain?
My simulations, the difference in maximum spl is less than 2dB >20Hz and less than 1dB >30Hz, would it be noticeable?
If I were to power a big concert hall with this sub, i would agree to sub_junkie and choose the 14Hz tuning or even 15Hz, but the target room does not look that big.
Even sealed might be a good option, as the TO already stated, but I would be curious to see him build an SLLT with the M21.
Greetings
RJdaMoD
 

·
Premium Member
Joined
·
348 Posts
Discussion Starter #18
Re: Maelstrom-21 giveaway build

I think I'm leaning toward sealed, because it has a much better chance of remaining part of my system then. When you build a sealed sub is it safe to assume you don't have to worry about the exact volume of the enclosure? ie. if my goal is a 7 cu ft box but I build it in an irregular shape so it is somewhere around that volume, does it matter what the exact volume is?
 

·
Registered
Joined
·
241 Posts
Re: Maelstrom-21 giveaway build

I think I'm leaning toward sealed, because it has a much better chance of remaining part of my system then. When you build a sealed sub is it safe to assume you don't have to worry about the exact volume of the enclosure? ie. if my goal is a 7 cu ft box but I build it in an irregular shape so it is somewhere around that volume, does it matter what the exact volume is?
No it doesn't matter if it's +/- 1 cu ft or so.
 
1 - 20 of 428 Posts
Top