Dave's Dual RL-P18 Sonotube Design/Build Thread

**Geoff St. Germain** · **12-01-07, 04:34 PM**

Quote:

Avus_M3 wrote:

Luckily for size I don't think there is a real big difference in apperance. In my modeling I am showing roughyly ~4.25" difference in height between the 650 and 700L size. There is a difference using the suggested 12hz tune on the 650L and 700L though. The 650L brings the FPR right around 193hz vs the 210hz for the 700L.

How high are you planning to cross these subs over to your mains?

**Avus_M3** · **12-01-07, 05:12 PM**

Planned on 80hz. IIRC my receiver has 150hz, 120hz, 80hz, and 60hz?

This link shows what I am running for the rest of the H/T speakers:

http://www.stereophile.com/floorloudspeakers/148/

Pioneer Elite:
TZ-F700 towers (12" woofer powered with a internal 300w bash amp, 6.5" mid, iris tweeter)
TZ-C700 center (2 powered 5.25" woofer with 150w internal bash amp and iris tweeter)
TZ-S700 surrounds (5.25" woofer with iris tweeter)

I picked them quite awhile ago.

**Avus_M3** · **12-01-07, 05:13 PM**

Here's the freq response of the towers:

Quote:

Fig.2 shows the on-axis response averaged across a 30-degree lateral window, combined with the nearfield woofer response (the latter derived from a complex sum of the woofer and port). Aside from a rise in the bass (the degree of which can be controlled by the woofer-level control) and a slight rise at 10kHz and above, the response is admirably flat, particularly in the region covered by the IRIS—which, from my listening tests and these measurements, appears to be a superbly designed device.

**Geoff St. Germain** · **12-01-07, 05:19 PM**

With those speakers I would even consider crossing over at 60 Hz. Regardless, the FPR of either 193 Hz or 210 Hz should be fine.

**Avus_M3** · **12-01-07, 05:41 PM**

700L using 12hz tune with 10" port:

Unless I am missing something (this could well be the case - I am still learning) the 10" port looks no bueno! I will play with the crossover and time delay when they are built. MANY graphs to come when that happens. I will need help deciphering all this stuff!!!

**SteveCallas** · **12-02-07, 01:22 PM**

A 53" port is almost guaranteed to make your first port resonance audible, I would definitely stay away from doing that. An 8" diameter port will work fine, I've yet to hear anything resembling a chuff.

As for 650 lietsr and a 13hz tune or 700 liters and a 12hz tune, it's pretty much splitting hairs, but all I would keep in mind is how soon room gain starts in your room. If your room is large and it starts down low, you may end up with a sloping downward FR even with room gain using too low of a tune. ~650 liters and a ~13hz tune should get you solid to 10hz in room.

**Avus_M3** · **12-02-07, 07:45 PM**

Solid to 10hz?? Nice! I asked in another thread if there is any way we can "predict" room gain which everyone said pretty much no. What about for modeling...is there an eq setting I could add to show some room gain? I tried a parametric EQ with a freq of 20hz q of 2 and 3db. Bumped up the low end very nicely but have no idea if that is realistic.

**SteveCallas** · **12-03-07, 02:43 AM**

We can calculate when room gain will start using a room node calculator and looking at the lowest frequency node. It's near impossible to predict how many dbs gain you will get though without testing....but based on the many measurements posted by enthusiasts, I'd say 4-8db/octave is common.

**Avus_M3** · **12-03-07, 04:19 PM**

I think the polls are kind of funny. I am comparing the polls from my thread here to the one at avsforum and there is a discernible difference. It seems voters here like it big and deep.

I am reffering to the vote count for the >13hz tune and 700L - 715L size.

**Avus_M3** · **12-03-07, 04:21 PM**

Quote:

SteveCallas wrote:

We can calculate when room gain will start using a room node calculator and looking at the lowest frequency node. It's near impossible to predict how many dbs gain you will get though without testing....but based on the many measurements posted by enthusiasts, I'd say 4-8db/octave is common.

Wow...that's quite a bit. I was pointed to this calculator on another thread:

http://www.hunecke.de/en/calculators/loudspeakers.html

Is there another you would recommend?

**Scott S** · **12-03-07, 04:22 PM**

I asked the same question when I was designing my box too...

Its hard to tell exactly the room gain you will get without measuring a sub, itself. I happened to get lucky with my guess. Turned out that with an 11hz tune I didnt have a rising response (for the most part) but nailed the room gain really well into a flat (pretty much) response.

Seems like your living room is pretty big so I wouldnt think you will get much, if any, room gain. That room needs some serious subwoofage.

Keep it around 650-750 per sono. Tune around 12-15hz and keep the port as 8 inches. Can't go wrong with that.

**Avus_M3** · **12-04-07, 02:42 PM**

Well, here's the pics I promised of the room. Forgive the laying around we had people over. For reference the screen is 56" and the tree is 9' tall. Ideally I would like to sell the TV and get a plasma I could mount on the fireplace and re-situate my setup. For now though it is how it is.

**Avus_M3** · **12-04-07, 02:47 PM**

This is how I would like it setup with the sono's on both sides with my towers in front and a plasma in the middle:

Notice that on both sides of the fireplace that there is a recessed area so the sub will be very close by to the wall - I imagine this will increase the room gain?:

**Avus_M3** · **12-04-07, 02:49 PM**

For size Reference:

Other side of TV - as you can see it's a TALL wall:

**Avus_M3** · **12-04-07, 02:49 PM**

Rear corners. The circle shows the pre-existing wiring from the prev owner. The square is the location I am thinking about mounting the rear channels. See any issues? They would be facing each other (inwards) unless I could get a good mount which I could point them towards the listening area?? Any ideas??:

**Avus_M3** · **12-06-07, 02:38 PM**

Well, it's official...my dad, wife, and brother-in-law (who was on board with the whole project) now all think I am loony! My wife is worried about me vibrating the house off the slab and sliding down the hill. She was wondering if our insurance would cover it? Those 18" RL's in person and some pics of the Crown amp have some serious impact on people?!?! The sh!ts really going to hit the fan when they see the tubes built

**Avus_M3** · **12-06-07, 03:17 PM**

Got some goodies BTW!

Galaxy CM-140:

Dual Power Heat Gun:

**Avus_M3** · **12-06-07, 03:18 PM**

Dayton BPA-38G HD Binding Post Pair Gold (A lot beefier than I thought):

Behringer UCA202 2-In/2-Out USB/Audio Interface S/PDIF Out:

**Avus_M3** · **12-06-07, 03:18 PM**

(2) Cast Frame #10-32 Speaker Mounting Kit

(2) Magnetic Grill Guides 3/8" Dia. x 0.2" H 8 Pcs

(2) Speaker Cabinet 3/8" Toe Spike Set 4 Pcs (Lost the spikes for my mains)

#10-32 Hurricane Nuts 50 Pcs

Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll (Before I saw the gasket included)

**Avus_M3** · **12-06-07, 03:19 PM**

Oh yeah almost forgot:

(30) Belkin Cat 5e 50 ft. Green Patch Cable (Hey, it was free!) Get to wire my house!

**Scott S** · **12-06-07, 06:44 PM**

Nice. You are all accessorized now.

No kidding about them binding posts. I thought they were nice and beefy. When on my big ol' boxes they look quite "regular" sized though. Lolz!

Any idea on when you are going to pick up your tube, start building and all that? Or have you yet to decide on a size/tune yet?

**Geoff St. Germain** · **12-06-07, 06:52 PM**

I just noticed you are going to be using a CE4000 (saw pics on that other forum). That's a good choice.

**Avus_M3** · **12-06-07, 10:19 PM**

Quote:

Scott S wrote:

Nice. You are all accessorized now.

No kidding about them binding posts. I thought they were nice and beefy. When on my big ol' boxes they look quite "regular" sized though. Lolz!

Any idea on when you are going to pick up your tube, start building and all that? Or have you yet to decide on a size/tune yet?

Well, instead of going to Whitecap and getting extorted I found a local supplier that will be able to get it considerably cheaper. The only problem is they don't stock the 30" normally so they will have to order the tube and pick it up from San Fransisco. It will most likely get built the week after Christmas due to the timing of everything.

**Avus_M3** · **12-06-07, 10:24 PM**

Quote:

Geoff St. Germain wrote:

I just noticed you are going to be using a CE4000 (saw pics on that other forum). That's a good choice.

I will post them here as well (the seller (Bradley) posted them in "the other forum").

**Avus_M3** · **12-06-07, 10:24 PM**

Fan modded

View Poll Results: What tuning point and size should I run?
<13hz	6	35.29%
13 - 13.5hz	4	23.53%
14hz - 14.5hz	7	41.18%
520 Liters	1	5.88%
650 Liters	5	29.41%
700 Liters - 715 Liters	6	35.29%
Multiple Choice Poll. Voters: 17. You may not vote on this poll

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