Rise of the Eighteens

**Blaser** · **01-27-09, 12:51 PM**

Quote:

Sonnie wrote:

If I bridge it 4 ohms... I get about 1950 watts. At 8 ohms bridged... it is about 1330 watts, still good power, just not taking advantage of all of its power.

Is it based on specs or measured? The TA-2400 Amp will have quite similar power at 8, 4 or 2 ohm load....

**Sonnie** · **01-27-09, 02:11 PM**

That is tested power.

What is the TA-2400?

**Ricci** · **01-27-09, 02:15 PM**

Quote:

Sonnie wrote:

Looks good. You could even increase the enclosure size by a few more ft each, decrease the vent length and raise the port resonance above 200hz. Splitting hairs...

**Sonnie** · **01-27-09, 03:00 PM**

This is actually for two drivers in one enclosure.

I am having a brain lapse...

Is that port length for both ports combined or each port?

**Ricci** · **01-27-09, 03:04 PM**

Quote:

Sonnie wrote:

This is actually for two drivers in one enclosure.

I am having a brain lapse...

Is that port length for both ports combined or each port?

Each. I knew it was 2 in one. I was thinking you could go to around 46-48ft total for the 2 and reduce the port length a bit. It's gonna be a Haus regardless. (I just edited my response right into your post on accident. Oops. Thought I hit the quote button.)

**Sonnie** · **01-27-09, 03:24 PM**

Yep... I looked at even 50ft^3 with 2 x 8" ports at 32" length each. It looks good too.

**SteveCallas** · **01-28-09, 06:01 PM**

Nice

Dual 6 ohm in series is 3 ohms - I'd do that and call it a day. It's not going to make a significant difference. I would strongly reconsider using just one amp though. With your Ebay know how I'm sure you can pick up another EP2500 extremely cheap

Unless the parameters changed, my modeling doesn't look like yours Sonnie. I'm looking at 50 cubes and two 8" ports that are 30" long each and I have a more pronounced low end. Are you using any filtering?

P.S. Sealed schmealed. Go for the gusto!

**Sonnie** · **01-28-09, 06:36 PM**

Kevin stated the Maelstroms I will be getting are dual 2 ohms... so I will either have to go with stereo 4 ohm or bridged 8 ohm.

Yes... I am using a 10Hz HPF in my modeling.

I think what I did was round the ports off to 32" and it changed the tune just a little bit from 12 Hz.

Here's the back wall plan...

These will be in a LLT manifold... ported out the front of the riser. Sitting on top of each driver cabinet is an EP2500.

**Blaser** · **01-31-09, 08:59 AM**

Quote:

Sonnie wrote:

That is tested power.

What is the TA-2400?

That's an amp Ilkka used extensively in his tests. He is the one that informed me about, and been using 2 of them since then.. Pretty stable 2 KW, it weighs about 60 ponds each!

http://www.thomann.de/gb/t-amp_ta2400.htm

**SteveCallas** · **01-31-09, 04:21 PM**

If you are going to use a 10hz highpass, you stand to gain by tuning it a little higher, mayve 14-15hz.

No desire for that second amp then?

**Sonnie** · **01-31-09, 09:27 PM**

Yeah... the second amp is a done deal. I may even do 21's if Kevin has them ready by then.

I think I will ease on up to about 15Hz. My AudioPulse 15's are at about 17Hz.

It appears 15Hz will require a pair of 18" ports 8" diameter in a 50ft^3 area.

**mayhem13** · **02-01-09, 01:39 AM**

With that kind of space, why stop at two and not 4 MalXs sealed in 120cuft with one amp at 2k? Bucks saved on amp better used on drivers IMO considering volume allowment. Usable response below 10khz seems like value in sealed vs ported to me. Here's a graph or two

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Room gain should help a bit below 20hz. This would be pretty scary with WOTW.

**Blaser** · **02-01-09, 08:58 AM**

Nice curve for sure!

**Sonnie** · **02-01-09, 08:11 PM**

I actually have 150ft^3 to work with... maybe even a little more. This is not 4 times VAS of the drivers combined, much less 10 times VAS. However, it does still look pretty good.

Here's what I come up with for comparison...

I think the question would be where will I gain the most for the most usable response range?

**mayhem13** · **02-02-09, 01:28 AM**

Measurements have shown as much as 6db or more in room gain below 20hz..it seems the lower you go, the greater the gain and the energy stored. I wouldn't be surprised if you picked up as much gain as needed where the ported alignment is more prodigious. The real sweetener is the stuff below 12hz, where your bowels kinda begin to twist a bit. A fellow AVS member posted a remastered copy of the early Titan missile program launches with heavy 5-10hz content. I'm actually afraid to try it out in the HT. My den system with dual 15's protested a bit but they don't go below 20hz anyway. If you're interested, i'll Email it to you...may help you make your decision on alignments.LOL

**Sonnie** · **02-02-09, 11:01 AM**

Yeah... see that is just it. I don't want to build a system for one or two instances of info below 10Hz that I will hardly ever be using. Nothing really impresses me about getting a few seconds or minutes of something that turns my insides a little.

**Blaser** · **02-02-09, 03:16 PM**

Sonnie, the tune is too high hor the yellow curve, you can use more extension...

**mayhem13** · **02-02-09, 06:35 PM**

Quote:

Sonnie wrote:

Yeah... see that is just it. I don't want to build a system for one or two instances of info below 10Hz that I will hardly ever be using. Nothing really impresses me about getting a few seconds or minutes of something that turns my insides a little.

I see your point but we're talking a difference of less than 3db at 16hz vs extension well below tune, plus no need for the high pass/subsonic of the port artifacts and phase issues when crossing to the mains. Plus less amplifier power.

**Sonnie** · **02-02-09, 07:33 PM**

What you see that I modeled above is with a high pass filter at 5Hz. May or may not need it, but I would not take a chance.

**Sonnie** · **02-02-09, 07:53 PM**

If I am going to go with 4 drivers... it appears tuning to 10Hz with an LLT will best the sealed and be much less stress on the excursion of the drivers ta boot.

For that matter... look what happens when I increase the enclosure volume to 100ft^3 on the LLT.

**Ricci** · **02-02-09, 11:16 PM**

If you're all of the way up to 100ft and 4 Mal-X's I'd just forget the ports and Mal-x's altogether and get 8 Fi IB 18's and run them in a manifold in the 150ft. Call it done. That's just me though.

**Sonnie** · **02-02-09, 11:30 PM**

lol... it's always fun spending someone else's money...

I am STOPPING at 4 X's.

**Ricci** · **02-03-09, 12:00 AM**

You ARE going with 4 M-X's?

. I thought you were still doing 2.

**mayhem13** · **02-03-09, 12:15 AM**

Quote:

Sonnie wrote:

I am STOPPING at 4 X's.

+1......yeah baby!

**SteveCallas** · **02-03-09, 12:23 AM**

Driver for driver, there is no scenario you can create in which sealed offers better overall performance.

My only question is why are you set on having a 10hz highpass?

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