12" JBL speaker $29 on black friday at Bestbuy - Page 49 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 938Likes
Reply
 
Thread Tools
post #1441 of 2550 Old 01-31-2019, 02:40 PM
Advanced Member
 
Join Date: May 2016
Location: Chicago, IL
Posts: 741
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 348 Post(s)
Liked: 489
2ohms on an inuke, either the 1000 or 3000 is quite a sweet spot.

I have gotten used 1000dsps for 125 a piece, and getting say 500 watts a channel with dsp at that price is awesome. I have run 4 drivers off a 1000 and a 3000 and it worked great either way.

Dont get hung up on power requirements. At worst you are a bit underamplified that is always an easy fix.
RoboAVS is offline  
Sponsored Links
Advertisement
 
post #1442 of 2550 Old 01-31-2019, 03:03 PM
Member
 
skipford's Avatar
 
Join Date: Mar 2009
Location: Denton Texas
Posts: 156
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 75 Post(s)
Liked: 44
Quote:
Originally Posted by EndersShadow View Post
Agreed, as long as you have enough power on the circuit to make sure the amp gets all it needs, your golden... The only thing larger boxes do is flatten the response, by bringing down the top end.





Yes.. per my sim's 4 of these perform the same as a single Ultimax 18 from about 40hz down, above that they perform BETTER than a Ultimax.

And when I bought them (27 per driver) for a cost of 120 you could get similar performance to a Ultimax UM18 (325 dollars)

Thats a price to performance ratio for sure!
Hi. Appreciate this thread so much. I've read about 10 pages but not the whole thing. I have lumber to begin building a SEALED riser out of T&G plywood (6 sided) and framing lumber. My plan was to install 4 JBLs in the face of the 14" riser. The riser is 12' wide, 6.5' deep, 14" tall. This (I think) is like making an infinite baffle but in a box. So it will be sealed (caulked at all joints, no ports) and a huge volume enclosure, all shared volume among the 4 drivers. My questions are:

1. Is firing the 4 drivers horizontal toward the back of the front row chairs just as good as firing them up underneath the 2nd row chairs?
2. Do I need to put polyfill in such a large sealed enclosure?
3. Is this all futile and am I better off making a smaller sealed enclosure?

Just having some gut checks before the weekend. Thanks for all of this information.
skipford is offline  
post #1443 of 2550 Old 01-31-2019, 03:43 PM
AVS Forum Special Member
 
trhought's Avatar
 
Join Date: Jan 2006
Location: Louisiana
Posts: 1,524
Mentioned: 102 Post(s)
Tagged: 0 Thread(s)
Quoted: 724 Post(s)
Liked: 1238
Quote:
Originally Posted by skipford View Post
Hi. Appreciate this thread so much. I've read about 10 pages but not the whole thing. I have lumber to begin building a SEALED riser out of T&G plywood (6 sided) and framing lumber. My plan was to install 4 JBLs in the face of the 14" riser. The riser is 12' wide, 6.5' deep, 14" tall. This (I think) is like making an infinite baffle but in a box. So it will be sealed (caulked at all joints, no ports) and a huge volume enclosure, all shared volume among the 4 drivers. My questions are:

1. Is firing the 4 drivers horizontal toward the back of the front row chairs just as good as firing them up underneath the 2nd row chairs?
2. Do I need to put polyfill in such a large sealed enclosure?
3. Is this all futile and am I better off making a smaller sealed enclosure?

Just having some gut checks before the weekend. Thanks for all of this information.
For number 1, I'm a big fan of below rather than behind. It all depends if you're on a concrete slab. If you're on a slab, it's more efficient to get tactile when the subs are below you bouncing the riser and isolating you from the concrete. You won't need much power to deliver the tactile sensation you're after. If you're on a flexible floor, horizontal firing will work also and deliver tactile to your chair and the floor below. But, you'll need more power to induce passive vibrating of your chair and floor rather than direct active vibrations you get with the sub below you in a riser.

For number 2, if your cabinet size is already big, no need to make it bigger which is what polyfill effectively does. If you're getting pesky cabinet resonances at higher frequencies, polyfill can be used, but with this sub cabinet being tuned to lower frequencies, that probably won't be a problem.

For number 3, it all depends on how much power you have and how much floor space you want to give up. If you have lots of power already and don't mind giving up floor or aisle space, then smaller cabinets behind will be fine if you're on a flexible floor. Personally, I love seeing the look on guests faces when the earth below them moves and they have no idea what's causing it. That effect is lost when they sit down in a chair and see menacing subwoofers ready to pummel them from behind. At that point, they're expecting to be blown away. I like to be more discreet about things and the LFE experience goes up exponentially with the element of surprise!
skipford, bimmaguy and Pradeep2 like this.
trhought is offline  
Sponsored Links
Advertisement
 
post #1444 of 2550 Old 02-01-2019, 08:38 AM
Senior Member
 
Chris Popovich's Avatar
 
Join Date: Dec 2005
Location: Phoenix AZ
Posts: 388
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 188 Post(s)
Liked: 165
Quote:
Originally Posted by skipford View Post
Hi. Appreciate this thread so much. I've read about 10 pages but not the whole thing. I have lumber to begin building a SEALED riser out of T&G plywood (6 sided) and framing lumber. My plan was to install 4 JBLs in the face of the 14" riser. The riser is 12' wide, 6.5' deep, 14" tall. This (I think) is like making an infinite baffle but in a box. So it will be sealed (caulked at all joints, no ports) and a huge volume enclosure, all shared volume among the 4 drivers. My questions are:

1. Is firing the 4 drivers horizontal toward the back of the front row chairs just as good as firing them up underneath the 2nd row chairs?
2. Do I need to put polyfill in such a large sealed enclosure?
3. Is this all futile and am I better off making a smaller sealed enclosure?

Just having some gut checks before the weekend. Thanks for all of this information.
1: My experiences are that back vs. up firing doesn't matter that much and is definitely room/couch/other speaker input dependent. My dozen are behind the couch, I have a concrete floor, my highest vibes are consistently in the z-axis. I do have a very aggressive house curve down low. I do think that under is a little more tolerant to higher crossover points. Maybe my couch is special. Go figure.
2: I wouldn't bother for that large of an enclosure.
3: IMO total cone area is a powerful thing and as the number of drivers increases and starts to look like an array, you start getting some cool benefits and better acoustic coupling. The only way to do this in the same space is to effectively make smaller enclosures (per driver). What's the "sweet spot" for total number of drivers vs. box volume per driver? You lose un-equalized low end capability when you drop volume but if you have a ton more drivers... it's not that hard to get it back assuming you have the amp/dsp. My gut feel is that the turning point is probably around 8 drivers for the average person, if you're under that number maybe worth while to err on larger enclosure side, if you have much more than 8 it starts to really not matter that much, the better acoustic coupling is NOT shown by sims. Gut guesses based on my own and anecdotal evidence. I would definitely rather have a dozen in tiny enclosures than 4 infinite baffle, again, assuming you have the amplifier and DSP.
bimmaguy likes this.

Last edited by Chris Popovich; 02-01-2019 at 08:44 AM.
Chris Popovich is offline  
post #1445 of 2550 Old 02-01-2019, 09:33 AM
AVS Forum Special Member
 
trilkb's Avatar
 
Join Date: Mar 2017
Location: Cincinnati, Oh
Posts: 1,204
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 655 Post(s)
Liked: 333
Im coming up with that enclosure being 79cuft lol.

What amp are you planning to run? you wont need much power at all.

- 6 BA CR6 array center channel, QSC AD-S82 L/R, 4 jbl 8330a surr , 8 jbl 12" subs w/Inuke 6000. JVC rs420, Denon x4000, Sony x800 -
trilkb is offline  
post #1446 of 2550 Old 02-01-2019, 05:24 PM
Member
 
skipford's Avatar
 
Join Date: Mar 2009
Location: Denton Texas
Posts: 156
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 75 Post(s)
Liked: 44
Quote:
Originally Posted by trilkb View Post
Im coming up with that enclosure being 79cuft lol.

What amp are you planning to run? you wont need much power at all.
I am running a Behringer NX3000D. This is on a second floor with wood framing.
skipford is offline  
post #1447 of 2550 Old 02-01-2019, 05:40 PM
AVS Forum Addicted Member
 
LastButNotLeast's Avatar
 
Join Date: Feb 2007
Location: 08077
Posts: 10,009
Mentioned: 72 Post(s)
Tagged: 1 Thread(s)
Quoted: 2518 Post(s)
Liked: 2151
I feel sorry for the folks on the first floor.


Did you really need to quote that entire post in your reply?
Welcome to AVS - Get out while you still can!
Don't guess, measure: https://www.avsforum.com/forum/91-au...l#post22789786
LastButNotLeast is offline  
post #1448 of 2550 Old 02-01-2019, 08:31 PM
Senior Member
 
bimmaguy's Avatar
 
Join Date: Dec 2012
Location: Winnipeg, Manitoba, Canada
Posts: 380
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 139 Post(s)
Liked: 164
Quote:
Originally Posted by LastButNotLeast View Post
I feel sorry for the folks on the first floor.


You mean the guys downstairs in the Cuban American embassy?


https://www.vox.com/2018/6/8/1743803...k-sonic-weapon

--------------------------------------------------------------------------------------------------------------
Subs are like pizzas: you get way more good stuff with the big ones.
https://www.avsforum.com/forum/155-di...uxl-build.html
https://www.avsforum.com/forum/155-di...-overture.html
bimmaguy is offline  
post #1449 of 2550 Old 02-02-2019, 07:15 AM
AVS Forum Special Member
 
trhought's Avatar
 
Join Date: Jan 2006
Location: Louisiana
Posts: 1,524
Mentioned: 102 Post(s)
Tagged: 0 Thread(s)
Quoted: 724 Post(s)
Liked: 1238
Quote:
Originally Posted by skipford View Post
Hi. Appreciate this thread so much. I've read about 10 pages but not the whole thing. I have lumber to begin building a SEALED riser out of T&G plywood (6 sided) and framing lumber. My plan was to install 4 JBLs in the face of the 14" riser. The riser is 12' wide, 6.5' deep, 14" tall. This (I think) is like making an infinite baffle but in a box. So it will be sealed (caulked at all joints, no ports) and a huge volume enclosure, all shared volume among the 4 drivers. My questions are:

1. Is firing the 4 drivers horizontal toward the back of the front row chairs just as good as firing them up underneath the 2nd row chairs?
2. Do I need to put polyfill in such a large sealed enclosure?
3. Is this all futile and am I better off making a smaller sealed enclosure?

Just having some gut checks before the weekend. Thanks for all of this information.
Skipford....just re-read this and noticed you mentioned sealing the bottom of the riser and using caulk at all joints. With the massive cabinet volume you have, I wouldn't bother with covering the bottom of the riser nor caulking any of the joints. The pressure inside those massive chambers won't be very much to worry about leakage.

Also, placing a cover on the bottom maximizes contact area with the floor which isn't good....with a sub riser, you're trying to minimize contact with the floor when sitting on top of the woofers.

If you decide to have horizontal firing smaller enclosures with more power and DSP, then yes, fully sealed and caulked is recommended as always.
trhought is offline  
post #1450 of 2550 Old 02-03-2019, 04:15 PM
Member
 
skipford's Avatar
 
Join Date: Mar 2009
Location: Denton Texas
Posts: 156
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 75 Post(s)
Liked: 44
Quote:
Originally Posted by trhought View Post

Skipford....just re-read this and noticed you mentioned sealing the bottom of the riser and using caulk at all joints. With the massive cabinet volume you have, I wouldn't bother with covering the bottom of the riser nor caulking any of the joints. The pressure inside those massive chambers won't be very much to worry about leakage.

Also, placing a cover on the bottom maximizes contact area with the floor which isn't good....with a sub riser, you're trying to minimize contact with the floor when sitting on top of the woofers.

If you decide to have horizontal firing smaller enclosures with more power and DSP, then yes, fully sealed and caulked is recommended as always.
Oh well too late. 🙂
Attached Thumbnails
Click image for larger version

Name:	IMG_20190203_175024_1549239284877.jpg
Views:	112
Size:	4.84 MB
ID:	2520090   Click image for larger version

Name:	IMG_20190203_153211_1549239296091.jpg
Views:	104
Size:	6.31 MB
ID:	2520092   Click image for larger version

Name:	IMG_20190202_183037_1549239314653.jpg
Views:	73
Size:	4.60 MB
ID:	2520094  
trhought likes this.
skipford is offline  
post #1451 of 2550 Old 02-03-2019, 04:51 PM
AVS Forum Special Member
 
trhought's Avatar
 
Join Date: Jan 2006
Location: Louisiana
Posts: 1,524
Mentioned: 102 Post(s)
Tagged: 0 Thread(s)
Quoted: 724 Post(s)
Liked: 1238
Quote:
Originally Posted by skipford View Post
Oh well too late. 🙂
Looks awesome....no problems with your design at all! With your horizontal firing arrangement, you'll be fine with sealed....will be much easier to make the cabinets smaller if you eventually want to DSP the low end down the road and not worry about exceeding Xmax on the JBL's.

Plus, for more tactile in the back row, you can still easily raise the riser off the ground to minimize contact area with the floor and maximize tactile for the back row. I'd recommend something like the grommets in the link below to raise the back riser off the floor for awesome back row tactile in addition to the "behind the seat" tactile for the front row.

These grommets are only .5" high and you'll probably be the only one who knows the riser is actually raised off the floor by such a small amount. You'll be amazed with the tactile response improvement in the back row when you raise that riser and separate it from the floor.

https://www.amazon.com/dp/B075KKRJXH...onvert-20&th=1
jeremiahsyoung likes this.
trhought is offline  
post #1452 of 2550 Old 02-05-2019, 10:27 AM
Member
 
skipford's Avatar
 
Join Date: Mar 2009
Location: Denton Texas
Posts: 156
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 75 Post(s)
Liked: 44
Quote:
Originally Posted by trhought View Post
Looks awesome....no problems with your design at all! With your horizontal firing arrangement, you'll be fine with sealed....will be much easier to make the cabinets smaller if you eventually want to DSP the low end down the road and not worry about exceeding Xmax on the JBL's.

Plus, for more tactile in the back row, you can still easily raise the riser off the ground to minimize contact area with the floor and maximize tactile for the back row. I'd recommend something like the grommets in the link below to raise the back riser off the floor for awesome back row tactile in addition to the "behind the seat" tactile for the front row.

These grommets are only .5" high and you'll probably be the only one who knows the riser is actually raised off the floor by such a small amount. You'll be amazed with the tactile response improvement in the back row when you raise that riser and separate it from the floor.

https://www.amazon.com/dp/B075KKRJXH...onvert-20&th=1
thank you!

Ok this is partially off topic but I don't know where to look:

1. What is the best way to connect the speaker wires to the woofer posts. These are mismatched metal tab connectors. The manual doesn't talk about this. Their diagram depicts a configuration that has two tabs on the pos. and neg. of each post.

2. For 4 drivers how would you connect to speakon connector? The Behringer allows you to connect 2 channels to one connector (Speakon 4 pole) but I think I would just connect to two.

3. How do you split the wire when going to a terminal and splitting to the next speaker?

I've made it to post 600 and still haven't found some of this information. I thank everyone for the information they've shared on this thread!
Attached Thumbnails
Click image for larger version

Name:	IMG_20190204_193331.jpg
Views:	40
Size:	704.5 KB
ID:	2520702  
skipford is offline  
post #1453 of 2550 Old 02-05-2019, 10:43 AM
AVS Forum Special Member
 
trilkb's Avatar
 
Join Date: Mar 2017
Location: Cincinnati, Oh
Posts: 1,204
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 655 Post(s)
Liked: 333
Dont mind this post. I had a brain fart.

- 6 BA CR6 array center channel, QSC AD-S82 L/R, 4 jbl 8330a surr , 8 jbl 12" subs w/Inuke 6000. JVC rs420, Denon x4000, Sony x800 -

Last edited by trilkb; 02-06-2019 at 02:41 PM.
trilkb is offline  
post #1454 of 2550 Old 02-05-2019, 01:06 PM
AVS Forum Special Member
 
jcmccorm's Avatar
 
Join Date: Mar 2001
Location: Madison, AL, USA
Posts: 4,523
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 611 Post(s)
Liked: 460
Quick question. I'm almost done with my first boxes for the CS1214's and I'm looking at the mounting holes on the drivers. There's a good bit of overlap of the foam on top covering up the mounting holes. There's not enough room for the screw-head for sure. What do you guys do? Peel back the foam and push it back down after you've mounted the driver? Ream it out with a drill-bit? Thanks...
jcmccorm is offline  
post #1455 of 2550 Old 02-05-2019, 02:44 PM
AVS Forum Special Member
 
Join Date: Aug 2016
Posts: 1,675
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 1012 Post(s)
Liked: 1261
I didn't care what the end result looked like so just screwed directly through the foam. The screws seated down fine.

Sent from my SM-N920V using Tapatalk
Pradeep2 is offline  
post #1456 of 2550 Old 02-06-2019, 02:27 PM
Member
 
skipford's Avatar
 
Join Date: Mar 2009
Location: Denton Texas
Posts: 156
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 75 Post(s)
Liked: 44
Quote:
Originally Posted by trilkb View Post
You are trying to get 2ohm on 2 channels right?

So you'd take the wires from your speakon, take the positive to one woofer and the neg to the other woofer, then run a wire from the negative of one directly to the positive of one.

Or are you trying to get a different ohm load?

Edit: wow, oops. You'd get 2 ohm that way. Fixed
The speakers are 4 ohm so not sure if 2 ohm would overload them. I only have one channel of speaker wire into the box.
skipford is offline  
post #1457 of 2550 Old 02-06-2019, 02:46 PM
AVS Forum Special Member
 
trilkb's Avatar
 
Join Date: Mar 2017
Location: Cincinnati, Oh
Posts: 1,204
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 655 Post(s)
Liked: 333
Hahaha, wow. Noone has caught my stupidity.....twice! Can't get my brain to explain something I've done lol.

If you wire my way you'll get 4 ohm on one channel. But its tricky to explain.

You have to series parallel them. Wire two pairs like I said. Then you need a way to parallel them. Series gets 2 4ohm driver to 8ohm, parallel the 2 8ohm loads back to 4.

So you basically need a distribution block. The easy way I did it was by using binding posts. Run your pos/neg from amp to binding posts, then use the binding posts to parallel each series. I'll draw or find a picture...

- 6 BA CR6 array center channel, QSC AD-S82 L/R, 4 jbl 8330a surr , 8 jbl 12" subs w/Inuke 6000. JVC rs420, Denon x4000, Sony x800 -
trilkb is offline  
post #1458 of 2550 Old 02-06-2019, 02:50 PM
AVS Forum Special Member
 
trilkb's Avatar
 
Join Date: Mar 2017
Location: Cincinnati, Oh
Posts: 1,204
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 655 Post(s)
Liked: 333
My link won't work and I can't attach pictures on my phone or on a computer, sorry man. I go to the website version and hit manage attachments and it just turns it back into the mobile version. My 2nd post on this forum was saying how much this site sucks on an android....and it still does!

Google series parrallel svc subwoofer and hope you find a picture

Edit, maybe success?

So you'll get 8ohm on each pair, then you just have to parrallel that. Twist/connect all three pos wires from amp/speakon and both pairs from the subs together, then same with negative. Binding posts with ring terminals on the wires make it clean, easy, and secure.
Attached Thumbnails
Click image for larger version

Name:	2_subs_SVC_2_ohm_mono_variation1_1549493742382.jpg
Views:	36
Size:	77.5 KB
ID:	2521316  
skipford likes this.

- 6 BA CR6 array center channel, QSC AD-S82 L/R, 4 jbl 8330a surr , 8 jbl 12" subs w/Inuke 6000. JVC rs420, Denon x4000, Sony x800 -

Last edited by trilkb; 02-06-2019 at 02:58 PM.
trilkb is offline  
post #1459 of 2550 Old 02-07-2019, 06:38 AM
Senior Member
 
iconrl's Avatar
 
Join Date: Jan 2007
Location: Oklahoma
Posts: 367
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 120 Post(s)
Liked: 109
If you're running all 4 off a single channel (bridged), you'll probably want this:





If you're running 2 on each channel, you'll probably want this:


Optoma HD37 on 138" DIY AT Screen | Infinity Beta 40s, Infinity Beta C250, Atlantic Technologies 224 SR
DIY Alpine SWS-15 in Cyclops box (LTD02 ported design) | Old Pioneer VSX-521 | Xbox One S
iconrl is offline  
post #1460 of 2550 Old 02-07-2019, 07:16 AM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 4,372
Mentioned: 413 Post(s)
Tagged: 0 Thread(s)
Quoted: 2798 Post(s)
Liked: 11943
Quote:
Originally Posted by trhought View Post
....will be much easier to make the cabinets smaller if you eventually want to DSP the low end down the road and not worry about exceeding Xmax on the JBL's.
Sorry, but I've never understood this logic. Making a cabinet smaller and less efficient just so you can push more power for the same SPL with more distortion just doesn't make any sense to me.

Take the Red Pill (BassEQ) BassEQ Demo Clips
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Custom Tapered Ported Volt-6 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #1461 of 2550 Old 02-07-2019, 08:07 AM
AVS Forum Special Member
 
trilkb's Avatar
 
Join Date: Mar 2017
Location: Cincinnati, Oh
Posts: 1,204
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 655 Post(s)
Liked: 333
at some point a larger cabinet becomes less efficent too though who knows what the happy medium is.

- 6 BA CR6 array center channel, QSC AD-S82 L/R, 4 jbl 8330a surr , 8 jbl 12" subs w/Inuke 6000. JVC rs420, Denon x4000, Sony x800 -
trilkb is offline  
post #1462 of 2550 Old 02-07-2019, 08:09 AM
AVS Forum Special Member
 
trhought's Avatar
 
Join Date: Jan 2006
Location: Louisiana
Posts: 1,524
Mentioned: 102 Post(s)
Tagged: 0 Thread(s)
Quoted: 724 Post(s)
Liked: 1238
Quote:
Originally Posted by aron7awol View Post
Sorry, but I've never understood this logic. Making a cabinet smaller and less efficient just so you can push more power for the same SPL with more distortion just doesn't make any sense to me.
110% agree....that's why I made one of my cabinets IB and the other open baffle.... They're both so efficient I only need about 80 watts per subwoofer for awesome ULF tactile via VNF/PV/shaker/floor isolation arrangements....all on concrete.

Details for each of my cabinets are in my theater build signature link below....Posts 10, 11, 12 and 13 in my build thread.

I've found most folks on AVS get caught up in the "moar power, moar speakers, moar DSP" mentality....especially here in the DIY speaker forum which is understandable. I prefer the less is more approach in stealth mode for that "ninja" sneak-up-and-surprise-you experience when the floor beneath you moves and guests have no idea what just happened

I've also found these efficient cabinet/driver arrangements allow for incredible tactile even at low listening volumes around -25 dB main volume settings. As reference is approached, the smiles only get bigger

As I'm getting more comfortable pushing my new modified open baffle configuration, I nudged the MV up to reference yesterday. Watched the WOW - Pods Emerge scene.....this time at reference which I had never done before since installing the OB mini-riser in the front row. My teeth started chattering and my eyeballs couldn't focus on my iphone when I looked down to read an alert that flashed on it.....freaking awesome! All with 80 watts per subwoofer.

That was insane....we usually listen to movies around -10dB MV and I'm still amazed how punchy the low end is in our theater now....I attribute that to the low cabinet pressures and higher sensitivities even down to 2Hz at relatively low main volumes levels.....loving it!
jeremiahsyoung and Nalleh like this.

Last edited by trhought; 02-07-2019 at 08:47 AM.
trhought is offline  
post #1463 of 2550 Old 02-07-2019, 08:50 AM
Senior Member
 
Chris Popovich's Avatar
 
Join Date: Dec 2005
Location: Phoenix AZ
Posts: 388
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 188 Post(s)
Liked: 165
Quote:
Originally Posted by aron7awol View Post
Sorry, but I've never understood this logic. Making a cabinet smaller and less efficient just so you can push more power for the same SPL with more distortion just doesn't make any sense to me.
I used to agree with you 100%, but I've since shifted my beliefs back to the infamous... "it depends".

Let's take gross examples. A single JBL in an infinite baffle vs a single JBL in 1 cu ft. They both displace the same amount of air. Music isn't sine waves, that IB woofer is going to eat up it's excursion in a hurry with low tones/subharmonics it isn't going to do a good job reproducing anyway, so real-world usage even if you eq the small box quite a bit it'll still play louder with the meat of most music before running into obvious distortion/excursion issues. The car audio guys have known this for years -the way it's usually described is a little off but the real key is to realize that music is comprised of a lot of different frequencies at the same time, not simple sine waves.

This changes if you have enough capability, i.e. much better woofers, a ton of them, or both. It also changes if you're making a true bottom-dweller (I cross mine over at about 30hz), hence the "it depends".

Really though the box is just behaving like a stronger high pass filter. You *could* do pretty much the opposite and have a huge box, then using DSP high pass the woofer until it "handles" just as much power as the same woofer in a tiny box (this would be pointless in 99.9% of applications). It's really just playing with three factors (power availability, DSP, and box size) that all play a role in final capability, box size being the mechanical aspect and controlling the air spring.

It just so happens that having a small box tends to be more useful to most of us in real life. Especially since we're going to need a couple dozen of these JBL's.....
Chris Popovich is offline  
post #1464 of 2550 Old 02-07-2019, 09:51 AM
AVS Forum Special Member
 
trhought's Avatar
 
Join Date: Jan 2006
Location: Louisiana
Posts: 1,524
Mentioned: 102 Post(s)
Tagged: 0 Thread(s)
Quoted: 724 Post(s)
Liked: 1238
^^^^ it all comes back to Hoffman's Iron Law....always tradeoffs with any speaker/cab approach. Small cab, deep bass, high sensitivity....you can only have 2 of the 3....choose which 2 you want and don't look back. 👍

If you choose low sensitivity (i.e. small cab and deep bass from Hoffman's Iron Law), it just costs more for amp power and DSP. There's no clear advantage to any approach. Many just choose small cabs because, hey, it's a small cab...lol.

Those with bigger cabs can get the same results with less money.

Last edited by trhought; 02-07-2019 at 10:04 AM.
trhought is offline  
post #1465 of 2550 Old 02-07-2019, 11:22 AM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 4,372
Mentioned: 413 Post(s)
Tagged: 0 Thread(s)
Quoted: 2798 Post(s)
Liked: 11943
Quote:
Originally Posted by Chris Popovich View Post
I used to agree with you 100%, but I've since shifted my beliefs back to the infamous... "it depends".

Let's take gross examples. A single JBL in an infinite baffle vs a single JBL in 1 cu ft. They both displace the same amount of air. Music isn't sine waves, that IB woofer is going to eat up it's excursion in a hurry with low tones/subharmonics it isn't going to do a good job reproducing anyway, so real-world usage even if you eq the small box quite a bit it'll still play louder with the meat of most music before running into obvious distortion/excursion issues. The car audio guys have known this for years -the way it's usually described is a little off but the real key is to realize that music is comprised of a lot of different frequencies at the same time, not simple sine waves.

This changes if you have enough capability, i.e. much better woofers, a ton of them, or both. It also changes if you're making a true bottom-dweller (I cross mine over at about 30hz), hence the "it depends".

Really though the box is just behaving like a stronger high pass filter. You *could* do pretty much the opposite and have a huge box, then using DSP high pass the woofer until it "handles" just as much power as the same woofer in a tiny box (this would be pointless in 99.9% of applications). It's really just playing with three factors (power availability, DSP, and box size) that all play a role in final capability, box size being the mechanical aspect and controlling the air spring.

It just so happens that having a small box tends to be more useful to most of us in real life. Especially since we're going to need a couple dozen of these JBL's.....
Quote:
Originally Posted by trhought View Post
^^^^ it all comes back to Hoffman's Iron Law....always tradeoffs with any speaker/cab approach. Small cab, deep bass, high sensitivity....you can only have 2 of the 3....choose which 2 you want and don't look back. 👍

If you choose low sensitivity (i.e. small cab and deep bass from Hoffman's Iron Law), it just costs more for amp power and DSP. There's no clear advantage to any approach. Many just choose small cabs because, hey, it's a small cab...lol.

Those with bigger cabs can get the same results with less money.
I wasn't saying there isn't a size benefit to a small box. Of course there is, but that is the only benefit as far as the tradeoffs of small vs. large. I was responding to trhought's statement, "....will be much easier to make the cabinets smaller if you eventually want to DSP the low end down the road and not worry about exceeding Xmax on the JBL's.", referring to making an existing large enclosure smaller, for the sake of being able to push more power into them. And in the case where low frequencies are eating too much excursion, that's exactly why we use HPFs. All this being said, if I were building sealed subs from scratch I wouldn't be trying to build them huge, mostly because diminishing returns start biting you pretty early on. But talking about the case mentioned where you already have a large enclosure, and you have to modify it to make the enclosure smaller (but only the internal enclosure, basically wasting the rest of the space), I don't see the point, just so you can throw more power at it but gain nothing. Really, once you get into these really big enclosure sizes, ported is so incredibly efficient, so that's the direction I'd be going.

Quote:
Originally Posted by trilkb View Post
at some point a larger cabinet becomes less efficent too though who knows what the happy medium is.
At what point does this happen? So you are saying IB is less efficient than large sealed? If that is actually true I bet the difference is negligible.

Take the Red Pill (BassEQ) BassEQ Demo Clips
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Custom Tapered Ported Volt-6 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #1466 of 2550 Old 02-07-2019, 11:40 AM
Senior Member
 
Chris Popovich's Avatar
 
Join Date: Dec 2005
Location: Phoenix AZ
Posts: 388
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 188 Post(s)
Liked: 165
I think you're missing something.

This is not a perfect analogy, so don't get too caught up on the specifics, but the overall principle remains.

Imagine a nice ported box tuned to, say, 35hz or so. No high pass filter. Now compare this to the same box with a high pass filter. Now we put on some music with bass. Which one will play louder, forget your sims, which one will handle more power before bottoming out? The one with the high pass filter. The reason why is that the system is no longer wasting so much excursion with the spectrum that is below the tuning of the box.

Likewise in a huge sealed box, at the lowest frequencies it takes very little power to get full excursion. This is why trhought is getting so much fun out of a handful of watts with his setup. That said, if he wanted the system to play the full bass spectrum loud and deep, and he put 500 watts or so to them, he would bottom the crap out of those poor JBL's unless he did something to curb the extreme excursion way down low (which is not what he'd want to do given the purposes of his system but I digress).

Do not get too caught up in compartmentalizing all the aspects of the system, when it's the program material played through driver in the box with the amp and the dsp in the room as heard from the listening position which defines the end result. A small enclosure is essentially a mechanical subsonic filter as compared to a large enclosure, increasing real-world-final-result loudness capability of the system with material that is most often present (i.e. above 30hz) in most music/etc.

A final note, the large enclosure-less-output-capability thing is invisible on a sim. Why? Sims describe capability given electrical and mechanical properties of the driver. They do not account for real music, and the inescapable fact that music is comprised of a spectrum of frequencies, it is not sine waves. If it's sine waves you want to play, a small box has zero advantages over a large box except size. With real music in a real room with real dsp and a real amp you will play the more-common aspect of the frequency spectrum much louder before running into excursion issues with a smaller box.
Chris Popovich is offline  
post #1467 of 2550 Old 02-07-2019, 11:50 AM
AVS Forum Special Member
 
trilkb's Avatar
 
Join Date: Mar 2017
Location: Cincinnati, Oh
Posts: 1,204
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 655 Post(s)
Liked: 333
Quote:
Originally Posted by aron7awol View Post


At what point does this happen? So you are saying IB is less efficient than large sealed? If that is actually true I bet the difference is negligible.
Im saying free air does nothing lol. Who knows what id get if I just started cutting holes in my drywalled 1700cuft room and used the unfinished part of my basement as the other part of the box. Im saying theres a limit each way. But between 10cuft, 20cuft and 1700cuft, who knows where the cut off is befor it essentially becomes free air (less efficient)

- 6 BA CR6 array center channel, QSC AD-S82 L/R, 4 jbl 8330a surr , 8 jbl 12" subs w/Inuke 6000. JVC rs420, Denon x4000, Sony x800 -

Last edited by trilkb; 02-07-2019 at 11:56 AM.
trilkb is offline  
post #1468 of 2550 Old 02-07-2019, 12:16 PM
AVS Forum Special Member
 
Nalleh's Avatar
 
Join Date: Aug 2014
Location: Norway
Posts: 3,720
Mentioned: 311 Post(s)
Tagged: 0 Thread(s)
Quoted: 2563 Post(s)
Liked: 3451
Quote:
Originally Posted by aron7awol View Post
Sorry, but I've never understood this logic. Making a cabinet smaller and less efficient just so you can push more power for the same SPL with more distortion just doesn't make any sense to me.
Maybe not quite what was meant here, but this is the one post that got me sold on more cheaper driver in small sealed boxes, ie 8 vs 4 drivers:

Quote:
Originally Posted by EndersShadow View Post
Here you go....

8 CS1214 each in a 1 cf box for a total of 8 cf (blue)
4 CS1214 each in a 2 cf box for a total of 8 cf (red)

So here is the thing.... I was right lol...

Excursion


The larger box can only handle 1200 watts COMBINED (300 watts per driver) before it gets close to XMax (I intentionally left some in the tank)
The smaller box can handle 5000 watts COMBINED (625 per driver) before getting around the same amount of cone movement....

However, look at the MASSIVE SPL differences...... especially in the "chest kick area (around 60hz).

@ 60hz: 132 v 123
@ 40hz: 128 v 120
@ 20hz: 115 v 109

PS I put a 4th order lowpass at 80hz since thats what most AVR's tend to set the LFE channel too, and thats what order filter they use as well...
SPL




Keep in mind, these are BEFORE room gain (which if you are super close, you may not get...

Sent from my iPhone using Tapatalk (so ignore any typos grammatical errors because my iPhone predictive text stinks)

Let’s face it: power is cheap, a NU6K is perfect for running these, and doubling up on drivers and these amp will get serious fast. And cheap

Dual Atmos Receivers - Atmos 13.1.8/DTS X 9.1.8/Auro 3D 13.1 - Denon AVCX8500H+AVRX7200WA - Klipsch+KEF - 6xSI18" - 12xJBL 12" w/6xSLAPS M12 downfiring VNF - 3x2 stacked Crowson MA - 4xBK-LFE - 6xNU6K(fan&trig mod) - Minidsp 10x10HD - Oppo UDP203 - XBox OneX - Apple TV4K - JVC RS600 Dreamscreen V2 120"- Philips 65OLED873.
Nalleh’s HT
Nalleh is offline  
post #1469 of 2550 Old 02-07-2019, 12:22 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 4,372
Mentioned: 413 Post(s)
Tagged: 0 Thread(s)
Quoted: 2798 Post(s)
Liked: 11943
Quote:
Originally Posted by Chris Popovich View Post
Imagine a nice ported box tuned to, say, 35hz or so. No high pass filter. Now compare this to the same box with a high pass filter. Now we put on some music with bass. Which one will play louder, forget your sims, which one will handle more power before bottoming out? The one with the high pass filter. The reason why is that the system is no longer wasting so much excursion with the spectrum that is below the tuning of the box.
You're comparing an improperly set up ported box with a properly set up ported box. Those subs have no business trying to play frequencies below tune. That's simply not what they were designed for. The meaningful comparison is a nice proper ported box with a bigger nice proper ported box, both with proper HPFs. The bigger box handles less power before bottoming out, but that excursion is translating to SPL, so that's just efficiency, not wasted excursion. And the benefits of the larger enclosure are huge in other ways, port output and the ability to tune lower and/or have a larger port to reduce or eliminate chuffing. For ported boxes, there is really no contest. Applying a proper filter to maximize output while protecting the driver is just part of proper design.

Quote:
Originally Posted by Chris Popovich View Post
Likewise in a huge sealed box, at the lowest frequencies it takes very little power to get full excursion. This is why trhought is getting so much fun out of a handful of watts with his setup. That said, if he wanted the system to play the full bass spectrum loud and deep, and he put 500 watts or so to them, he would bottom the crap out of those poor JBL's unless he did something to curb the extreme excursion way down low (which is not what he'd want to do given the purposes of his system but I digress).
As I said, sealed boxes are a different story, and diminishing returns kick in quite early, but there is still a significant difference up to a certain point. And really, what the additional size does for you is shift the frequency at which the driver is power-limited vs. excursion-limited (by increasing the efficiency down low). If a driver is power-limited at a frequency, it is not able to maximize excursion, and thus not able to maximize output. By shifting the limitation to excursion, you are unlocking additional SPL. And that's really my point, excursion is output. Maximizing excursion (while of course staying within the mechanical limits of the driver) is really the name of the game. A bigger box is able to strike this balance just as well, it's just a matter of execution, and it has the additional output advantage of being excursion-limited in areas where a smaller sub would be power-limited.

Quote:
Originally Posted by Chris Popovich View Post
Do not get too caught up in compartmentalizing all the aspects of the system, when it's the program material played through driver in the box with the amp and the dsp in the room as heard from the listening position which defines the end result. A small enclosure is essentially a mechanical subsonic filter as compared to a large enclosure, increasing real-world-final-result loudness capability of the system with material that is most often present (i.e. above 30hz) in most music/etc.

A final note, the large enclosure-less-output-capability thing is invisible on a sim. Why? Sims describe capability given electrical and mechanical properties of the driver. They do not account for real music, and the inescapable fact that music is comprised of a spectrum of frequencies, it is not sine waves. If it's sine waves you want to play, a small box has zero advantages over a large box except size. With real music in a real room with real dsp and a real amp you will play the more-common aspect of the frequency spectrum much louder before running into excursion issues with a smaller box.
What I'm saying doesn't only apply to sine-waves, nor have I ever suggested that real content, whether it's music or movie, consists of sine waves. The sine waves are individual components of the complex waveform, so they are still there, there are just many things happening at once. That doesn't change the fact that the system needs to be tuned properly to strike the balance I mentioned of giving maximum output while staying within the mechanical limits. That is true regardless of content. Assuming that has been done, the bigger box has the advantage down low, not the other way around. But like I said, the differences for sealed are minor once you get to reasonable sizes, so it's not that important either way. That's why it's important for me to note again that I was referring to a case where someone would modify an existing large box to enclose the driver in a smaller space, essentially just to put a mechanical filter on it, when they could instead put an electronic filter on it with more control and end up with more output. That is what I said doesn't make any sense to me.

Take the Red Pill (BassEQ) BassEQ Demo Clips
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Custom Tapered Ported Volt-6 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #1470 of 2550 Old 02-07-2019, 12:24 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 4,372
Mentioned: 413 Post(s)
Tagged: 0 Thread(s)
Quoted: 2798 Post(s)
Liked: 11943
Quote:
Originally Posted by trilkb View Post
Im saying free air does nothing lol. Who knows what id get if I just started cutting holes in my drywalled 1700cuft room and used the unfinished part of my basement as the other part of the box. Im saying theres a limit each way. But between 10cuft, 20cuft and 1700cuft, who knows where the cut off is befor it essentially becomes free air (less efficient)
Whoa, whoa, whoa. Free-air where the front wave cancels the back wave is a whole different animal from IB. What you'd get if you cut holes and sent the back wave into your basement is IB. That would super-efficient, not the other way around.

Take the Red Pill (BassEQ) BassEQ Demo Clips
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Custom Tapered Ported Volt-6 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
Sponsored Links
Advertisement
 
Reply DIY Speakers and Subs

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


Forum Jump: 

Posting Rules  
You may not post new threads
You may not 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 code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off