Monkey see, monkey do... two RL-P18s for me too! - Page 10 - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #91 of 151 Old 11-05-07, 02:21 PM
Elite Shackster
 
Owen Bartley's Avatar
OJ
 
Join Date: Oct 2006
Location: Toronto, Ontario
Posts: 2,073
My System
Re: Monkey see, monkey do... two RL-P18s for me too!

Bradley, wow. Really really great work on that sub! I hate when I come in late to good build threads because I love watching them step by step. Yours is coming along very nicely! First of all, a dual RL-p18 is a great project in any case, but when someone puts in the attention to detail that you are, it makes it really fun to watch. I love the rounded internal edges (I did the same in my Tempest, but not nearly as nicely as you have) and the port flares. I'll be watching closely from now on for sure!

P.S. Is that an S4? - Nevermind, I just read the last page and it is. Very nice... but keep the MDF dust off it!


- OJ -

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Last edited by Owen Bartley; 11-05-07 at 02:33 PM.
Owen Bartley is online now  
Sponsored Links
Advertisement
 
post #92 of 151 Old 11-05-07, 03:26 PM Thread Starter
Senior Shackster
Bradley
 
Join Date: Aug 2007
Location: Seattleland
Posts: 146
Re: Monkey see, monkey do... two RL-P18s for me too!

Thanks, Owen! I must confess that I haven't update this build thread in a while. The first subwoofer is actually done now. The only thing left is paint which I plan to do later when the second cabinet is completed.

Here are some recent pics:



Subwoofer's view of the room:


Another view of the toys:
Bradley is offline  
post #93 of 151 Old 11-05-07, 03:55 PM Thread Starter
Senior Shackster
Bradley
 
Join Date: Aug 2007
Location: Seattleland
Posts: 146
Re: Monkey see, monkey do... two RL-P18s for me too!

Quote:
blaser wrote: View Post
I am waiting to see some REW graphs man!!!
That is definitely on my "to do" list! I did take some preliminary measurements with the Radio Shack digital SPL meter with C weighting. Here are some of the uncorrected readings I got at 2 meters from the sub in-room:

99 dB @ 12.5 Hz (near clipping)
100 dB @ 13.0 Hz (near clipping)
108 dB @ 20.0 Hz (no sign of clipping on amp)

The amp is a QSC RMX 2450, rated at 750 watts into into 4 ohms stereo at 1 kHz. I'm just running the sub off one channel in stereo mode for now. A bit nervous about slamming the cone at frequencies below tune, so I am very hesitant to run it bridged.

Playing around with the signal generator, I observed cone excursion to reach a minimum right around 13 Hz, so that would appear to be the effective tune of the system. I was shooting for 14.5 Hz but I don't mind it being lower.
Bradley is offline  
 
post #94 of 151 Old 11-05-07, 03:59 PM
Senior Shackster
Ben
 
Join Date: May 2006
Posts: 343
Re: Monkey see, monkey do... two RL-P18s for me too!

Tuning frequency would show almost zero cone excursion - not peak cone excursion
Bent is offline  
post #95 of 151 Old 11-05-07, 04:03 PM Thread Starter
Senior Shackster
Bradley
 
Join Date: Aug 2007
Location: Seattleland
Posts: 146
Re: Monkey see, monkey do... two RL-P18s for me too!

Right. That's why I said it reached a minimum.
Bradley is offline  
post #96 of 151 Old 11-05-07, 04:44 PM
Elite Shackster
 
SteveCallas's Avatar
Steve
 
Join Date: Apr 2006
Posts: 2,398
Re: Monkey see, monkey do... two RL-P18s for me too!

Do be careful with high output sine waves below tuning, that is just asking for trouble. When it comes to real material, you have nothing to fear, go ahead and bridge the amp.

How are you liking it so far? I'll wait to see your in room FR, but I've noticed a trend that orientations with the driver front firing often don't have as smooth a natural FR at the seat as those with it downfiring.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
SteveCallas is offline  
post #97 of 151 Old 11-05-07, 06:06 PM Thread Starter
Senior Shackster
Bradley
 
Join Date: Aug 2007
Location: Seattleland
Posts: 146
Re: Monkey see, monkey do... two RL-P18s for me too!

Quote:
SteveCallas wrote: View Post
Do be careful with high output sine waves below tuning, that is just asking for trouble. When it comes to real material, you have nothing to fear, go ahead and bridge the amp.
I am being VERY careful with the test tones. That's why I didn't go lower than 12.5 Hz with the high SPL measurement. By the time you get down to 12 Hz the cone really starts moving. Oddly enough, the 20 Hz test spooked me more than the 12.5 Hz test did with the high SPL and cone movement.

Quote:
SteveCallas wrote: View Post
How are you liking it so far? I'll wait to see your in room FR, but I've noticed a trend that orientations with the driver front firing often don't have as smooth a natural FR at the seat as those with it downfiring.
Interesting. This sub could be converted to down firing pretty easily, with the only real issue being the location of the speaker terminals.

To answer your question... I'm liking it a lot! I went out and bought a copy of War of the Worlds yesterday and I have to say the LFE output was just totally insane. Good lord... I feared the cone of the RL-P18 might jump right out of the basket. I had to leap up from my seat and lower the gain on the amp about 3 times as the clipping light was going NUTS! That movie easily has more LFE output than anything I've ever seen/heard. And yes, the RL-P18 delivered the goods with great big gooey gobs of infrasonic goodness. Getting the second sub completed will be nice so there's a little more headroom and low end extension.

Getting this sub done and putting it to the test has really enabled me to appreciate the low tune/high displacement combo. After hearing this beast reproduce test tones all the way down to 12.5 Hz and belch out all of the LFE material on WoTW, I can say unequivocably that building a sub capable of going well below 20 Hz was a worthwhile venture! Seriously... the pair of Def Tech PF15TL+ subs I had before simply DID NOT EXIST below 20 Hz. So I am now hearing and feeling things never heard & felt before. The difference in output is truly staggering.

Thanks again to everyone here on the Shack that helped to inspire me and guide me along the way during my build.
Bradley is offline  
post #98 of 151 Old 11-05-07, 07:04 PM
Elite Shackster
 
SteveCallas's Avatar
Steve
 
Join Date: Apr 2006
Posts: 2,398
Re: Monkey see, monkey do... two RL-P18s for me too!

Bridging the amp should eliminate the clipping


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
SteveCallas is offline  
post #99 of 151 Old 11-05-07, 08:33 PM
Senior Shackster
Platinum Supporter
 
Rodny Alvarez's Avatar
Rodny
 
Join Date: Apr 2006
Location: Millbrook AL
Posts: 828
Re: Monkey see, monkey do... two RL-P18s for me too!

Nice work Bradley!!!

What finish are you going with?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Rodny Alvarez is offline  
post #100 of 151 Old 11-05-07, 08:33 PM
Senior Shackster
Ben
 
Join Date: May 2006
Posts: 343
Re: Monkey see, monkey do... two RL-P18s for me too!

My appologies for being assumptive - as well as curt...
my eyes saw what they wanted to see, rather than what was really there.

I was rushed in my needless reply..., but also wanted to say the job looks very good.
Bent is offline  
Reply

Bookmarks

Tags
monkey , rlp18s

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome