Rise of the Eighteens - Page 4 - Home Theater Forum and Systems - HomeTheaterShack.com

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post #31 of 137 Old 01-27-09, 02:24 PM Thread Starter
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Re: Rise of the Eighteens

Yep... I looked at even 50ft^3 with 2 x 8" ports at 32" length each. It looks good too.
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post #32 of 137 Old 01-28-09, 05:01 PM
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Re: Rise of the Eighteens

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!


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post #33 of 137 Old 01-28-09, 05:36 PM Thread Starter
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Re: Rise of the Eighteens

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.
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post #34 of 137 Old 01-31-09, 07:59 AM
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Re: Rise of the Eighteens

Quote:
Sonnie wrote: View Post
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

ASME AI
Yamaha RX-V2500, Wharfedale Diamond 9.6 Fronts, Wharfedale Diamond CM Center, Diamond DFS Surround and rear, Behringer FBQ 2496, Dual RL-P18s 625L LLTs, Dual TA-2400 Pro (2 * 2000 W Amp), Samsung HD870 DVD player, Carada BW 16:9 106" screen, Epson TW-2000, 60 Gb PS3
Important HT proverbs:
- "You can never have too much headroom" (talking about bass)
- "you can never have too big a screen" (talking about still pictures)


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post #35 of 137 Old 01-31-09, 03:21 PM
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Re: Rise of the Eighteens

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?


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post #36 of 137 Old 01-31-09, 08:27 PM Thread Starter
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Re: Rise of the Eighteens

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.
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post #37 of 137 Old 02-01-09, 12:39 AM
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Re: Rise of the Eighteens

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

Rise of the Eighteens-cb-response-maelstrom-18.gif

Rise of the Eighteens-cb-excursion-maelstrom-18.gif

Room gain should help a bit below 20hz. This would be pretty scary with WOTW.
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post #38 of 137 Old 02-01-09, 07:58 AM
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Re: Rise of the Eighteens

Nice curve for sure!

ASME AI
Yamaha RX-V2500, Wharfedale Diamond 9.6 Fronts, Wharfedale Diamond CM Center, Diamond DFS Surround and rear, Behringer FBQ 2496, Dual RL-P18s 625L LLTs, Dual TA-2400 Pro (2 * 2000 W Amp), Samsung HD870 DVD player, Carada BW 16:9 106" screen, Epson TW-2000, 60 Gb PS3
Important HT proverbs:
- "You can never have too much headroom" (talking about bass)
- "you can never have too big a screen" (talking about still pictures)


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post #39 of 137 Old 02-01-09, 07:11 PM Thread Starter
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Re: Rise of the Eighteens

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?
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post #40 of 137 Old 02-02-09, 12:28 AM
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Re: Rise of the Eighteens

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
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