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Sonosub - Bottom cone?

post #1 of 18
Thread Starter 
I'm soon starting a sonosub/RL-p15 project and I have a "bottom detail" question.

Check out the attached illustrations. I haven't seen a "bottom cone" on any of the sonosubs around, but I think I've seen such a thing on a couple of non-DIY downfiring subs. Are these cones included just to look cool or do they actually have a purpose acustically?

My guess is that (in theory) you can have less clearance between the driver and the bottom plate with such a construction, but I may be totally wrong...

Maybe it's better to just have good clearance between the driver and the bottom plate. I'm not afraid of heights anyway (as long as I'm at the bottom lookin up, that is ).
LL
LL
post #2 of 18
Polk Audio does this with their "Power port". Im not sure if it would make much difference though.
post #3 of 18
Hi,

Bass frequencies are omni-directional. I can't see any real advantage to doing this except for making the bottom look nice.

Best,
Mark
post #4 of 18
Well, under the assumption that sound waves exhibit wave-like behavior, you might theoretically be redirecting more of the sound and its energy away to the sides, rather than having it reflect back up and push against the driver. ???
post #5 of 18
Thread Starter 
Quote:
Originally Posted by Josuah View Post

Well, under the assumption that sound waves exhibit wave-like behavior, you might theoretically be redirecting more of the sound and its energy away to the sides, rather than having it reflect back up and push against the driver. ???

Yes, I was also thinking along those lines...
post #6 of 18
I have seen them used in conjunction with bottom firing ports which would help reduce turbulence and the infamous "chuffing" of an undersized port. It would help direct the airflow in and out of the port. However, I do not believe it would make a difference redirecting sound at subwoofer frequencies.
post #7 of 18
To expand on robfive's train of thought, not only would the cone affect chuffing it would also affect the port tuning.

As far as helping to alleviate mass loading, I think it would have to be a really sloped cone to help, and then you have to wonder whats really improving things the cone or the extra space. You would then have to choose between the extra height for the cone, or just saying ( add your own expletive!), and having +4in legs.
post #8 of 18
Maybe I should do this on my Baker's dozen.
post #9 of 18
Quote:
Originally Posted by RuneW View Post

I started a separate thread about "sonosub bottom cone". As you can read from that thread, the avs forum users weren't overly enthusiastic about the idea... (but I still think that a bottom cone feels right )



Hope you dont' mind me posting your image here, RuneW. I will impliment both of our ideas with this conical deflector on my Sonosub. I'm almost CERTAIN that there will be a small amount of enthusiasm about this strange project. This was my first post (see #3):

http://www.avsforum.com/avs-vb/showt...&&#post8003152

Separate thread will start once things get rolling. I was able to "sneak" in an order last Tuesday, got my TC-2000 Thursday!




I've already started to machine / build the conical deflector, "layertone" style (as the diyaudio.com & fullrangedriver.com forum users refer my method of lamination). Here is a Bosch router bit 45-degree in a ER-25 tool holder...



6 layers, 15 total...

post #10 of 18
Thread Starter 
Quote:
Originally Posted by layertone View Post

Hope you dont' mind me posting your image here, RuneW. I will impliment both of our ideas with this conical deflector on my Sonosub. I'm almost CERTAIN that there will be a small amount of enthusiasm about this strange project. This was my first post (see #3)

Separate thread will start once things get rolling. I was able to "sneak" in an order last Tuesday, got my TC-2000 Thursday!

I've already started to machine / build the conical deflector, "layertone" style (as the diyaudio.com & fullrangedriver.com forum users refer my method of lamination). Here is a Bosch router bit 45-degree in a ER-25 tool holder...

No problem all!

Congrats with the nice driver (nice picture btw ). And I REALLY envy your power tools!
post #11 of 18
Quote:
Originally Posted by RuneW View Post

No problem all!

Congrats with the nice driver (nice picture btw ). And I REALLY envy your power tools!

Power tools? Gave up my table / jig saw about 4 years ago.... threw it out the back yard from fustration!

you can see some more of it here (most viewed)...

http://fullrangedriver.com/gallery/t...bum=topn&cat=0
post #12 of 18
Very interesting stuff here layertone. Looking forward to watching this project progress.
post #13 of 18
Thinking out loud here... I have my mind set on the bottom cone... and a top one too! For sure I will need multiple standoffs / bolts going inside the sono to support the weight.
post #14 of 18
Thread Starter 
Quote:
Originally Posted by layertone View Post

Power tools? Gave up my table / jig saw about 4 years ago.... threw it out the back yard from fustration!

you can see some more of it here (most viewed)...

http://fullrangedriver.com/gallery/t...bum=topn&cat=0

Wow!
post #15 of 18
Quote:
Originally Posted by meeks32 View Post

Polk Audio does this with their "Power port". Im not sure if it would make much difference though.

The cone at the bottom of a Polk speaker is an integral part of the port design and tuning, it's not in front of the woofer. (I have all the Polk documentation regarding the design and engineering of Power Ports)

Were there any benefit from a cone in front of the woofer you can bet commercial builders would have done this long ago.
post #16 of 18
Quote:
Originally Posted by Thomas-W View Post

Were there any benefit from a cone in front of the woofer you can bet commercial builders would have done this long ago.

Steve stated this in a PM: "the thing is, I have a hard time seeing any commercial audio company selling such a large product."

Not trying to start any fires, but from reading about LLT's and huge benefits, I haven't seen any commercial builders make LLT's.
post #17 of 18
I think layertone works as a costume maker for Madonna...







C'mon...... no one else thought of this one??
post #18 of 18
I'd be a millionaire if I did! LOL, thanks for the humor!
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