Dual RL-p18 LLT begun

[brucek]

Can you tell me how long the port is Tom?

Are you using the D4 driver with the two coils in parallel?

brucek

[Jerm357]

Thats hilarious

[SteveCallas]

This guy is nuts.............I love it!

[tjambro]

brucek wrote:

Can you tell me how long the port is Tom?

It's an 8" diameter port 25 5/8" long, not counting the flare at the end. I used a 3/8" roundover bit for the flare. I was shooting for an effective volume of 550L with a 14.5Hz tuning. Unibox said the port should be 25.94" long. I'm probably gonna be just under 550L by the time it's all done.

Are you using the D4 driver with the two coils in parallel?

brucek

Yes, one D4 driver with dual coils in each box running in parallel. Each driver should see 900 watts per channel into 2 ohms with my Carvin HD1800.

-Tom A.

[tjambro]

Rodny Alvarez wrote:

I hope your back still in one piece!

Let's just say I won't be getting in the boxes anymore!

-Tom A.

[tjambro]

SteveCallas wrote:

This guy is nuts.............I love it!

Coming from a guy who thinks a couple of 6.5' tall obelisks in the middle of his den which happens to be in an apartment is not enough, I feel like I am among family.



-Tom A.

[brucek]

Yes, one D4 driver with dual coils in each box running in parallel

Yeah, I guess the SoundSplinter site show the Re and BL for series coils, so I had to use the trick with WINISD to calculate them when in parallel.

WINISD shows the 8" port at 27.5" inches with one end flared in a 545 liter box tuned at 14.5Hz.

It looks real good at least to my novice playing around. The experts could comment.

Here's SPL of one box with 900 watts applied with a 10Hz, 1st order highpass filter to account for the electronics dropoff down low and a single BFD filter at 48Hz with a cut of -6dB with a Q of 0.7
I guess room gain comes into play and maybe the BFD filter would be less (or none).

SPL




Here's the cone excursion at full power. The Xmax is 27.4, so that looks good to me. It's shows only a bit out of the linear range at full power. The graph goes below Xmax just above 500 watts. That seems good.

EXCURSION @ full power



The velocity exceeds the 5% of speed of sound (~17m/sec) when full power is applied which I'm told is into the chuffing range. But who runs full power. At 500 watts it's about 19 m/sec

VELOCITY



And of course you have two of these monster.

Here's a tip: Don't sit in it when playing full power.

brucek

[tjambro]

brucek wrote:

WINISD shows the 8" port at 27.5" inches with one end flared in a 545 liter box tuned at 14.5Hz.

I haven't messed with WINISD much. If it's not too much trouble, can you tell me what tuning I can expect with a 26" port assuming the same 545L?

Here's SPL of one box with 900 watts applied with a 10Hz, 1st order highpass filter to account for the electronics dropoff down low and a single BFD filter at 48Hz with a cut of -6dB with a Q of 0.7
I guess room gain comes into play and maybe the BFD filter would be less (or none).

I don't have a BFD yet. I plan on running it without at first and then pick one up if absolutely necessary. I guess I need to get REW installed so I can measure, huh? I plan on doing a FR on my current pair of Def Tech 2002 (each one has a built in 12" sub) just for kicks. I'm sure the SS's will dig much deeper.

Here's a tip: Don't sit in it when playing full power.

brucek

Excellent advice!

-Tom A.

[brucek]

I haven't messed with WINISD much. If it's not too much trouble, can you tell me what tuning I can expect with a 26" port assuming the same 545L?

>>>> 14.83Hz at 26" with a 8" port with one end flared at 545L.

brucek

[tjambro]

brucek wrote:

>>>> 14.83Hz at 26" with a 8" port with one end flared at 545L.

brucek

Thanks, I can probably live with that.

-Tom A.