RL-p18 Sonotube thoughts...

**bnw** · **07-29-07, 11:25 AM**

Thanks again! Wow I just saw you home & car equiptment list.
Talk about rock'in the Kaspar!

**SteveCallas** · **07-29-07, 03:12 PM**

I'll just second or third to go with the D2s. A single EP2500 should be fine for now, as dual 18" LLTs being fed with only 100 watts a piece for instance would still be PLENTY powerful. If you do then ever go to dual P2500s, you'll have even more headroom on tap, though hypothetically, you may not even need it

This "Brotherhood of Bass" group as I once referred to it has achieved global expansion pretty quickly. Phase III of my plan will be the....ehh, too soon

**bnw** · **07-29-07, 03:24 PM**

Hmmm, well in that case I've got this http://www.belcantodesign.com/prod_evo4.html
hanging around not earning its keep, so maybe I'll start off with it for the test run.
What do you think?

**bnw** · **07-30-07, 10:01 PM**

OK, just ordered my router... always wanted an excuse to get one.
So, what size/type bits do I need for MDF and the SonoTube? Oh yeah, and who makes that really nice circle jig?

**Zene** · **07-31-07, 01:12 AM**

Should have put here, so I will....
I looked at the SS 18" as an LLT and shelf was only down 4dB from reference. Could pertain to Rl-p, also.
Isn't that too high considering room gain? Is there an accepted shelf goal?
My PA P.Audio 18" shelf is -15dB from reference and -10dB with respect to 80hz.
I suggest everyone read or re-read your initial LLT post. http://www.hometheatershack.com/foru...explained.html
BTW, thanks for personal help, Steve. Saved me from getting kicked out of the house having two subs.
Zene

**bnw** · **07-31-07, 03:04 PM**

Quote:

brucek wrote:

That was my suggestion above - it gives you more options. Each sub enclosure will stand alone at 4 ohms total (using a D2 in each enclosure with the voice coils in series). You can use a stereo amp with each channel feeding a 4 ohm sub.

Then later you can add a second amp and have both amps bridged to 4 ohms, each feeding its own 4 ohm sub...

brucek

Sorry Bruce,
I guess it was a bit for me to absorb in all the excitement of planning my build. Ahh, its sinking in now. I had the parallel series thing wrong in my head. Went on an "electrical explained" website with illustrations... now I've got it -Thanks again

**SteveCallas** · **07-31-07, 07:42 PM**

If you have a current sub, measure it close mic'ed and then again at your seat - the difference in gain, ignoring peaks and nulls, is the room gain. You can determine an ideal tuning for yor LLT based on that

**bnw** · **07-31-07, 08:56 PM**

Well, right now I only have the four 7" woofers in my B&W 605's fed by the two 130W plate amps. Do they count? I have a sub demo disk and can get an RatShack spl meter. Is that how you do it?

**brucek** · **07-31-07, 10:08 PM**

Quote:

I have a sub demo disk and can get an RatShack spl meter. Is that how you do it?

No, you would use REW. But the 7" subs won't go down low enough to give you a good indication of room gain at 15Hz for example..... better to just assume 6dB.....

You will need to get REW working though, because you'll require it to set up an EQ when you're done the sub.

brucek

**Blaser** · **08-02-07, 01:08 PM**

Quote:

But the 7" subs won't go down low enough to give you a good indication of room gain at 15Hz

Why? is this sub highly tuned?

**brucek** · **08-02-07, 01:15 PM**

Quote:

Why? is this sub highly tuned?

The small driver would not produce much output at 15hz........

**Blaser** · **08-02-07, 01:29 PM**

well well well

do not underestinate the power of tuning and box volume...Also there are 4 of them... But I don't know... here is a simple room gain similation program...it works pretty accurate with my room.

**brucek** · **08-02-07, 02:44 PM**

Quote:

do not underestinate the power of tuning and box volume

You can only squeeze so much out of it....

Quote:

Also there are 4 of them

Makes them louder - not lower.

brucek

**Blaser** · **08-02-07, 03:25 PM**

Well Bruce if you insist,

I am not talking specially of the drivers above (I don't know them) but

15Hz is reachable by a 7" driver or even smaller (driver parameters will vary from a driver to another depending on which will be how good the driver will produce 15 Hz signal, and not its size).

4 * 7" will have about 36% more cone area compared to a single 12" driver, and if all other parameters are equal, and if the 4* 7" drivers are suitably ported or "LLTed" they will basically put some serious 15 Hz signal.

But again I don't know about the case of this thread

**bnw** · **08-02-07, 04:12 PM**

While this subject is beyond my knowlege, I can add that their FR is rated 20 Hz although I would think they're a bit out of their comfort zone at that point.

**Blaser** · **08-02-07, 04:20 PM**

therefore you have to follow the precious advice of Brucek

**Zene** · **08-02-07, 09:15 PM**

Let's try this ... isobaric (clam shelled) PL-p 18's in Sonotube LLT.
1/2 the size and all the benefits of coupling, guessing around 200 L. Only a 4" port required.
Four of these in a room though rather silly for us cheapies would certainly smooth things out. 200 watts could get the job done?
Zene

**Adam321** · **08-04-07, 10:54 AM**

Just wanted to put my two cents in on the choosing between the d2 and the d4, because this comes up alot. I think it all depends on how many drivers you are going to run. My rule of thumb is to always get a 4 ohm load and run the amp(s) in bridged mono for max output,(as long as the amp you choose can run bridged mono) So, one driver, buy the D2, two drivers buy the D4. I.E. witht the D4 you would wire the coils in series for 8 ohms, and then run the two drivers in parrallel for a 4 ohm overall load. Connect to the amp in bridged mono for maximum output from the amp. With an EP2500 it would be approx. 2000 watts.

**bnw** · **08-04-07, 03:50 PM**

Quote:

Adam321 wrote:

Just wanted to put my two cents in on the choosing between the d2 and the d4, because this comes up alot. I think it all depends on how many drivers you are going to run. My rule of thumb is to always get a 4 ohm load and run the amp(s) in bridged mono for max output,(as long as the amp you choose can run bridged mono) So, one driver, buy the D2, two drivers buy the D4. I.E. witht the D4 you would wire the coils in series for 8 ohms, and then run the two drivers in parrallel for a 4 ohm overall load. Connect to the amp in bridged mono for maximum output from the amp. With an EP2500 it would be approx. 2000 watts.

Thanks Adam, I think now I have an opinion in favor of every combination, LOL
I do see what you mean though. My plan (today) is to go D2 and wire the Vcoils in series and use my Bel Canto bridged mono (600W@4ohms) to start. If I do the second Sono I'll probably get the EP2500 and run it 2 channel, so the D2's will still be the way to go. (right?)

**Adam321** · **08-04-07, 07:36 PM**

Quote:

bnw wrote:

Thanks Adam, I think now I have an opinion in favor of every combination, LOL
I do see what you mean though. My plan (today) is to go D2 and wire the Vcoils in series and use my Bel Canto bridged mono (600W@4ohms) to start. If I do the second Sono I'll probably get the EP2500 and run it 2 channel, so the D2's will still be the way to go. (right?)

Well, not exactly. That is why you really have to decide ahead of time on whether or not you are going to have two drivers. With the one driver you are going the right way. I am surprised the Bel Canto can do bridged mono into 4 ohms. Most consumer amps will only do bridged into 8 ohms or more.

If you are sure you are going to eventually have 2 drivers, get the D4's. You can run the Bel Canto bridged into 8 ohms, until you get your second driver.

**bnw** · **08-06-07, 08:53 PM**

Quote:

Adam321 wrote:

Well, not exactly. That is why you really have to decide ahead of time on whether or not you are going to have two drivers. With the one driver you are going the right way. I am surprised the Bel Canto can do bridged mono into 4 ohms. Most consumer amps will only do bridged into 8 ohms or more.

If you are sure you are going to eventually have 2 drivers, get the D4's. You can run the Bel Canto bridged into 8 ohms, until you get your second driver.

Hey Adam I think you're right. I spoke with Bel Canto today by e-mail and i think thats what they'd like to see as well using the D4. Can you read these and see if it makes sense to you? Its a little bit different type of bridged. Perhaps I should post this in the Amp section.
http://www.stereotimes.com/amp100702.shtml
http://www.belcantodesign.com/prod_evospecs.html

**Adam321** · **08-07-07, 09:43 AM**

Quote:

bnw wrote:

Hey Adam I think you're right. I spoke with Bel Canto today by e-mail and i think thats what they'd like to see as well using the D4. Can you read these and see if it makes sense to you? Its a little bit different type of bridged. Perhaps I should post this in the Amp section.
http://www.stereotimes.com/amp100702.shtml
http://www.belcantodesign.com/prod_evospecs.html

From reading those articles it certainly looks like you can bridge each pair of channels into 4 ohms to get 600 WPC x 2 at 4 ohms. Very impressive. If thats the case I would definitely get the D4. You could bridge each set of channels and run 600 watts to each voice coil. Then if you get a second D4 you could run the each woofer at 300 watts per voice coil. (one channel to each voice coil at four ohms).

**bnw** · **08-08-07, 07:25 AM**

Quote:

Adam321 wrote:

From reading those articles it certainly looks like you can bridge each pair of channels into 4 ohms to get 600 WPC x 2 at 4 ohms. Very impressive. If thats the case I would definitely get the D4. You could bridge each set of channels and run 600 watts to each voice coil. Then if you get a second D4 you could run the each woofer at 300 watts per voice coil. (one channel to each voice coil at four ohms).

OK, one other ? if you don't mind. My PrePro (Emotiva DMC-1) http://www.emotiva.com/expandedpages/dmc1expanded.html
only has one balanced sub output. Do I just get a one to two splitter from say Guitar Center to get the LFE to both sides of the amp, or do I just run the single ended sub1, sub2 outputs? I'd rather run the balanced output with its greater signal strength so as to not have to run the amp quite as hard.

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