JBL 'M2' Master Reference Monitor - Page 94 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 2257Likes
Reply
 
Thread Tools
post #2791 of 4705 Old 05-19-2017, 10:05 AM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by Mark Seaton View Post
I have rejected dozens of Ultimax drivers over time that don't make our cut. An Ultimax 18 dropped in a typical DIY box won't have the articulation out of the box that a SubMersive has. DIYers will have to use less power, and be cautious of amp or driver overload noises. No one will tell you to use a 2 Ohm rated amp to drive 4 Ultimax 18" drivers, and unless you've measured the result down to how much and what type of stuffing is in exactly what size box, I wouldn't recommend it either. All that translates to probably 2-3dB measured lower peak output to be safe and 6-12dB lower max playback levels per woofer, without a 5 year warranty. I'd also argue our enclosures are better constructed and look nicer than 95% of DIY boxes if aesthetics have any value in your personal equation.
oh cmon, like nobody can hook up an SP or other worthwhile amp to some sealed subs and apply dsp/limiters correctly.... I understand you have a product to sell, but not everyone who DIYs is a moron.
notnyt is offline  
Sponsored Links
Advertisement
 
post #2792 of 4705 Old 05-19-2017, 11:14 AM
AVS Forum Special Member
 
Mark Seaton's Avatar
 
Join Date: Jul 2000
Location: Chicago, IL, USA
Posts: 6,960
Mentioned: 210 Post(s)
Tagged: 0 Thread(s)
Quoted: 906 Post(s)
Liked: 2567
Quote:
Originally Posted by notnyt View Post
oh cmon, like nobody can hook up an SP or other worthwhile amp to some sealed subs and apply dsp/limiters correctly.... I understand you have a product to sell, but not everyone who DIYs is a moron.
There's a lot more there than just the limiter. Unless you've tested many of the drivers, a DIYer has no way of knowing what the expected limits are vs other issues happening before those limits causing either distortions or highly audible sounds of distress. While anyone can, I suspect you would be surprised if you interviewed DIYers to see how many measured the behavior of the sub itself (NF in room to confirm performance is fine), and see similarly surprising responses when asking if they went through testing for any leaks, squeaks, or rattles with a test signal. While a few do, plenty of DIY-favorite amps don't have internal limiting, and a MiniDSP 2x4 does not include any features for limiting. Quick setting of limiters can result in noises that sound similar to hard clipping and just protect from death while still making bad noises. If more optimally dialed in, it's possible to increase useful playback levels by 6-12dB with very minimal audible changes in the first 6dB of that, and nothing offensive well beyond.

You are an experienced builder with a good deal of knowledge. Inside an echo chamber of a small DIY community it may feel like most should know these things and practice them, but that has not been the reality I have observed, where such cases are the exception. It has little to do with what someone *could* do, but rather is all about what people take the time and effort to do, or have the persistence to figure out the issue when things don't behave as expected. Companies producing other subwoofers on the market *could* do many of the things you might in a build, or similar things I do. The reality is that many don't. The reasons vary from feeling it doesn't matter, not seeing it as worth the time and effort, or in fact not knowing any better. Before starting Seaton Sound I thought the relatively elegant/simple sealed subwoofer that wasn't electronically castrated with a useful, starting low frequency extension was too obvious an offering to start out with and I started experimenting with more exotic solutions. Even after a few years of pointing other manufacturers to offer the right combo, almost none bothered, so I did. Fortunately there are many more such offerings available today, but most every manufacturer chooses to do things a bit different. The things I mentioned aren't about cost, they're about polish and refinement of the end product, and willingness to hold things up rather than ship out a an under-performing item.

Mark Seaton
Seaton Sound, Inc.
"Make no little plans; they have no magic to stir men's blood..." Daniel H. Burnham
Mark Seaton is offline  
post #2793 of 4705 Old 05-19-2017, 12:11 PM
Advanced Member
 
Jsin_N's Avatar
 
Join Date: Dec 2009
Posts: 756
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 442 Post(s)
Liked: 195
I don't feel I have the rapport to argue this any further, but engineering a product and protecting your brand/name is a different thing than DIY'ing a capable subwoofer system and standing on your own failure/success. Apples versus apple marketing/quality control
Jsin_N is offline  
Sponsored Links
Advertisement
 
post #2794 of 4705 Old 05-19-2017, 12:46 PM
AVS Forum Addicted Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 12,116
Mentioned: 66 Post(s)
Tagged: 0 Thread(s)
Quoted: 3152 Post(s)
Liked: 3101
Quote:
Originally Posted by notnyt View Post
oh cmon, like nobody can hook up an SP or other worthwhile amp to some sealed subs and apply dsp/limiters correctly.... I understand you have a product to sell, but not everyone who DIYs is a moron.
The assumption that anybody can hook one up is as dangerous as the assumption nobody can IMO. And I do not think either extreme was in Mark's reply.

Quote:
Servo drive is to cover up inadequately designed woofers with an over complex mechanism. Maybe if they used pid control or a smarter algo than just basic feedback it might be better, but still pointless. The extra money you spend on electronics to drive it is better spent on proper equipment.
I used a PID controller with a decent (IRS) woofer over 30 years ago and that started me down the servo path. Nothing offered comparable performance at the time anywhere close to my budget and space constraints. Servo subs have tested well, and not, just like conventional designs. There are many ways to achieve a good design but denigrating everyone else seems to me to be in poor taste.

Whatever - Don
shivaji likes this.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
post #2795 of 4705 Old 05-19-2017, 01:34 PM
AVS Forum Special Member
 
Blackdevil77's Avatar
 
Join Date: Feb 2012
Location: Nassau County, Long Island, New York
Posts: 1,644
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 492 Post(s)
Liked: 228
Cool stuff Mark! My vote goes for F18's, but I think anything you get will likely be fantastic, I'm sure. The S2S-EX's are great to, just a bit more complicated to implement and since you wanted simplicity, the F18's seemed like the best bet. I'm probably gonna replace my Submerisve HP's for F18's eventually, just for size reasons. I'll probably keep one though, I love these things.

Quote:
Originally Posted by AudioJosh View Post
How much plumbing? Plumbing is easy enough to re-route and that might not cost you a lot. I learned to plumb myself, so I have saved costly dollars in the past with upgrades and repairs.
Not much, just one main pipe, and the sewage access under the ground that we need access to.

I'm not too sure about what I'm looking at as far as the plumbing goes, so I took a little video showing what is behind my screen. The room is certainly there for a baffle wall, but the plumbing on one side and electric box on the other complicates things slightly.

Blackdevil77 is online now  
post #2796 of 4705 Old 05-19-2017, 01:53 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by DonH50 View Post
The assumption that anybody can hook one up is as dangerous as the assumption nobody can IMO. And I do not think either extreme was in Mark's reply.



I used a PID controller with a decent (IRS) woofer over 30 years ago and that started me down the servo path. Nothing offered comparable performance at the time anywhere close to my budget and space constraints. Servo subs have tested well, and not, just like conventional designs. There are many ways to achieve a good design but denigrating everyone else seems to me to be in poor taste.

Whatever - Don
I didn't say anybody could. There are plenty of people I wouldn't trust with a saw

That said, there's also the middle ground, like projects Mark worked on with the X21 which are good for people who aren't able to properly build an enclosure.

I'm just saying there are lots of proven designs available, and even decent flat packs like from diysoundgroup...

You have to really screw something up to use the same woofer and have 12db less output...

As for servo subs, I'm not aware of any of them that are outperforming conventional designs around the same price point... You can check figures on data-bass.
notnyt is offline  
post #2797 of 4705 Old 05-19-2017, 02:00 PM
AVS Forum Special Member
 
Mark Seaton's Avatar
 
Join Date: Jul 2000
Location: Chicago, IL, USA
Posts: 6,960
Mentioned: 210 Post(s)
Tagged: 0 Thread(s)
Quoted: 906 Post(s)
Liked: 2567
Quote:
Originally Posted by notnyt View Post
I didn't say anybody could. There are plenty of people I wouldn't trust with a saw

That said, there's also the middle ground, like projects Mark worked on with the X21 which are good for people who aren't able to properly build an enclosure.

I'm just saying there are lots of proven designs available, and even decent flat packs like from diysoundgroup...
Thank you. There are certainly plenty of quality kits and solutions. It's not all that different from various levels of DIY/kit projects around the house. They make perfect sense for some, and none for others. Quite often those on the extremes of that spectrum can't fathom why the other would choose such an option...

Quote:
You have to really screw something up to use the same woofer and have 12db less output...
Please look back where I very specifically mentioned 2-3dB less measured output, which is what you are talking about. The 6-12dB difference is real world playback of demo scenes and typical dynamics. IOW set each to the same level and how high does the owner turn the main volume before having to back off.

Mark Seaton
Seaton Sound, Inc.
"Make no little plans; they have no magic to stir men's blood..." Daniel H. Burnham
Mark Seaton is offline  
post #2798 of 4705 Old 05-19-2017, 02:01 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by Mark Seaton View Post
There's a lot more there than just the limiter. Unless you've tested many of the drivers, a DIYer has no way of knowing what the expected limits are vs other issues happening before those limits causing either distortions or highly audible sounds of distress. While anyone can, I suspect you would be surprised if you interviewed DIYers to see how many measured the behavior of the sub itself (NF in room to confirm performance is fine), and see similarly surprising responses when asking if they went through testing for any leaks, squeaks, or rattles with a test signal. While a few do, plenty of DIY-favorite amps don't have internal limiting, and a MiniDSP 2x4 does not include any features for limiting. Quick setting of limiters can result in noises that sound similar to hard clipping and just protect from death while still making bad noises. If more optimally dialed in, it's possible to increase useful playback levels by 6-12dB with very minimal audible changes in the first 6dB of that, and nothing offensive well beyond.

You are an experienced builder with a good deal of knowledge. Inside an echo chamber of a small DIY community it may feel like most should know these things and practice them, but that has not been the reality I have observed, where such cases are the exception. It has little to do with what someone *could* do, but rather is all about what people take the time and effort to do, or have the persistence to figure out the issue when things don't behave as expected. Companies producing other subwoofers on the market *could* do many of the things you might in a build, or similar things I do. The reality is that many don't. The reasons vary from feeling it doesn't matter, not seeing it as worth the time and effort, or in fact not knowing any better. Before starting Seaton Sound I thought the relatively elegant/simple sealed subwoofer that wasn't electronically castrated with a useful, starting low frequency extension was too obvious an offering to start out with and I started experimenting with more exotic solutions. Even after a few years of pointing other manufacturers to offer the right combo, almost none bothered, so I did. Fortunately there are many more such offerings available today, but most every manufacturer chooses to do things a bit different. The things I mentioned aren't about cost, they're about polish and refinement of the end product, and willingness to hold things up rather than ship out a an under-performing item.
It sounds like you're talking about a first time DIYer without any support or guidance. That I can agree on you with. There are also some people who DIY that are just copying something else or don't really know what they're doing, so again, you have a point there, but it sounded like nobody can get it right from what you were saying..

That said, MiniDSP does in fact have a limiter in some of their plugins, though t's not frequency dependent. The crown amps have a decent DSP built in, and you can route a sidechain to a limiter affecting only a certain frequency range. I'm fairly certain Brian can do some basic dsp programming for the SP amps as well.

I know you make quality subs, yours and Jeff's are the only ones I recommend to anyone looking to purchase prebuilt units.

Last edited by notnyt; 05-19-2017 at 02:06 PM.
notnyt is offline  
post #2799 of 4705 Old 05-19-2017, 02:05 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by Mark Seaton View Post


Please look back where I very specifically mentioned 2-3dB less measured output, which is what you are talking about. The 6-12dB difference is real world playback of demo scenes and typical dynamics. IOW set each to the same level and how high does the owner turn the main volume before having to back off.
Ah, wasn't that clear and was reading from a cell phone.. Yeah, there's a lot of corners cut in DIY and people trying to keep the budget low. Many using the inuke amps which are toys compared to the SP stuff.. though price per watt with DSP on those is still pretty great, just not something I'd use. I still have one on my transducers I'm looking to replace... I like the dynamic eq features in there.... I just don't like the cooling.

Last edited by notnyt; 05-19-2017 at 02:08 PM.
notnyt is offline  
post #2800 of 4705 Old 05-19-2017, 03:09 PM
AVS Forum Special Member
 
Blackdevil77's Avatar
 
Join Date: Feb 2012
Location: Nassau County, Long Island, New York
Posts: 1,644
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 492 Post(s)
Liked: 228
On a side note, these M2's sound fantastic on their own with music and no subs. The way they sound is basically proving to me that I'm having a hell of a time getting the subs to jive with the mains, especially since I can only set one delay for the sub output, and the 2 subs are in different locations. I was playing around with an SPL meter and sine waves with REW to try and get the delays right. I don't think I'm gonna be able to get it right unless I can delay the subs separately. Oh well, another thing on the to do list lol.
Blackdevil77 is online now  
post #2801 of 4705 Old 05-19-2017, 04:34 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by Blackdevil77 View Post
On a side note, these M2's sound fantastic on their own with music and no subs. The way they sound is basically proving to me that I'm having a hell of a time getting the subs to jive with the mains, especially since I can only set one delay for the sub output, and the 2 subs are in different locations. I was playing around with an SPL meter and sine waves with REW to try and get the delays right. I don't think I'm gonna be able to get it right unless I can delay the subs separately. Oh well, another thing on the to do list lol.
minidsp
notnyt is offline  
post #2802 of 4705 Old 05-19-2017, 04:39 PM
AVS Forum Special Member
 
Blackdevil77's Avatar
 
Join Date: Feb 2012
Location: Nassau County, Long Island, New York
Posts: 1,644
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 492 Post(s)
Liked: 228
Quote:
Originally Posted by notnyt View Post
minidsp
Impeccable timing lol, I was just looking at them on their site. I'm guessing one of these

https://www.minidsp.com/products/min...p-balanced-2x4

or this if I just want Dirac to do the work, don't want to hack up my XLR cables and want to part with an additional $675.

https://www.minidsp.com/dirac-series/ddrc-22a
Blackdevil77 is online now  
post #2803 of 4705 Old 05-19-2017, 04:41 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by Blackdevil77 View Post
Impeccable timing lol, I was just looking at them on their site. I'm guessing one of these

https://www.minidsp.com/products/min...p-balanced-2x4

or this if I just want Dirac to do the work, don't want to hack up my XLR cables and want to part with an additional $675.

https://www.minidsp.com/dirac-series/ddrc-22a
I'd go with the 2x4hd over the 2x4.... also, xlr cables are cheap, monoprice has solid ones

Dirac is nice though, if you wanna go that path.
Blackdevil77 likes this.
notnyt is offline  
post #2804 of 4705 Old 05-19-2017, 04:51 PM
AVS Forum Special Member
 
torii's Avatar
 
Join Date: Mar 2015
Posts: 6,703
Mentioned: 47 Post(s)
Tagged: 0 Thread(s)
Quoted: 3325 Post(s)
Liked: 1877
no matter what rew says I adjust by ear in the end
Scotth3886 likes this.

Power: Marantz sr7008, NAD C 275Bee x 2, Video: Oppo 103, Samsung 75un6300
Speakers: Focal aria 948, Focal cc900, Klipsch synergy KSF 10.5, Magnepan LRS
Subs: Rythmik FV25HP, Rythmik FV15HP
torii is online now  
post #2805 of 4705 Old 05-19-2017, 07:39 PM
Member
 
jtwrace's Avatar
 
Join Date: Oct 2013
Location: Orlando, FL
Posts: 133
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Liked: 65
Quote:
Originally Posted by notnyt View Post

I know you make quality subs, yours and Jeff's are the only ones I recommend to anyone looking to purchase prebuilt units.
You don't like the Funk Audio offerings?
jtwrace is offline  
post #2806 of 4705 Old 05-19-2017, 08:14 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by jtwrace View Post
You don't like the Funk Audio offerings?
If you want to overpay for something that has a nice finish, ok I guess... What you can get from JTR or Seaton will stomp anything they offer dollar for dollar. Not even close.
notnyt is offline  
post #2807 of 4705 Old 05-20-2017, 05:15 AM
Member
 
jtwrace's Avatar
 
Join Date: Oct 2013
Location: Orlando, FL
Posts: 133
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Liked: 65
Quote:
Originally Posted by notnyt View Post
If you want to overpay for something that has a nice finish, ok I guess... What you can get from JTR or Seaton will stomp anything they offer dollar for dollar. Not even close.
Yeah I wasn't looking for dollar for dollar cost. I was looking for the "best" and the driver measurements by http://www.data-bass.com/home are hard to argue. My (2) Funk 21.0LX will be in a basic black enclosure since I'm not into the fancy finishes.
jtwrace is offline  
post #2808 of 4705 Old 05-20-2017, 06:10 AM
AVS Forum Special Member
 
Gooddoc's Avatar
 
Join Date: Oct 2004
Posts: 8,658
Mentioned: 181 Post(s)
Tagged: 0 Thread(s)
Quoted: 3687 Post(s)
Liked: 3283
Quote:
Originally Posted by Mark Seaton View Post
You would want 2 powered units for 4 corner positions. As much as I and most other calibrators have tried, I have yet to see a tangible benefit to sending a different signal to subwoofers that are both at the front wall or in front corners. Same for a pair at the rear of the room, or pairs at similar front-back depth on the side walls. Some day I could see separate signals useful if using a tool like Dirac Unison in rooms that aren't structurally symmetrical left-right, such as where one wall has a concrete foundation behind it, and the other is drywall studs to a utility closet or other room, but typically the different interaction vs placement with the boundaries is desired to create a complimentary blend. The whole conceptual benefit of placing a pair of subs in front corners or 1/4 points is based on sending them identical signals. It falls apart if you feed them differently!

I strongly recommend separate signals for the front and rear grouping of subs, with a pair front and rear being a great solution for most rooms. In most cases all that is needed is an appropriate delay applied to the rear group of subs. On rare occasion you might back down the level of the rear subs if they are super close to your seats. In the majority of cases this creates a great platform to deliver great bass to the listening area empirically through measurements and iterative adjustments. The hardest part is taking care to label measurements so you can look back at what you measured. The current versions of our amplifiers even have a delay knob to facilitate this exact configuration if the surround processor is happier or not capable of applying the delay. In small room acoustics, subwoofers operate on total power put into the room. It's near impossible to level match subs with widely varying frequency responses, as you can only average or pick a frequency. With identical subwoofers it is much better to "gain match," where each sub is contributing equally, and thereby one won't run out of gas with the others not contributing equally. A handful of measurements moving your current subs into position could give high confidence or show limitations in such a solution. So long as you are not sitting at the midpoint front-back in the room, and both locations don't produce coincident troughs in the response, you should be good with the 4 corner approach.

You could alternately pay Keith Yates Design for their BassCAMP optimization, but the accuracy is based on the accuracy of the model of the room. It is highly accurate in rooms of their design with well known acoustic properties, with uncertainty increasing as the acoustic properties of the boundaries become less well known or more variable.

The SubMersive HP and F2 packages are still current for a reason, and they will continue on well into the future. The F2 package (dimension drawings here) is the smallest footprint with the trade off of a 35.5" height. The chamfered rear corners also allow it to be tucked tight in a corner if space allows.

I haven't made formal announcements yet, but I did just finish up two new 18" packages which pack the same performance of the F18 into either a much shallower 12" deep package, or smaller front profile of 20" square. I posted some info on these in Art Sonneborn's thread where the first of the DS18-20 was installed. The first of the shallow DS18-12 were just delivered to AVS member Lasalle's home for his "LOGE" project.

Thanks Mark!
Gooddoc is offline  
post #2809 of 4705 Old 05-20-2017, 11:54 AM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by jtwrace View Post
Yeah I wasn't looking for dollar for dollar cost. I was looking for the "best" and the driver measurements by http://www.data-bass.com/home are hard to argue. My (2) Funk 21.0LX will be in a basic black enclosure since I'm not into the fancy finishes.
I think Funk makes a better 18 than they do a 21. The THD measurements for the 21 get up there
notnyt is offline  
post #2810 of 4705 Old 05-20-2017, 12:52 PM
AVS Forum Special Member
 
Kain's Avatar
 
Join Date: Dec 2001
Location: Dubai, UAE
Posts: 4,187
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1933 Post(s)
Liked: 813
What pre/pro would you guys recommend for an M2-based setup for around $5,000? I see the Anthem AVM 60 is widely used here. Is it a good match?
Kain is offline  
post #2811 of 4705 Old 05-20-2017, 02:30 PM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by notnyt View Post
I think Funk makes a better 18 than they do a 21. The THD measurements for the 21 get up there
Which measurements are you comparing to reach this conclusion?

Do realize that distortion of a sealed system depends on a lot more than the driver alone. The internal volume of the box has a major impact on low frequency distortion. The cone size, independent of the motor design, suspension parts, and internal volume, also influences distortion of the end product.
awediophile is offline  
post #2812 of 4705 Old 05-20-2017, 02:46 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by awediophile View Post
Which measurements are you comparing to reach this conclusion?

Do realize that distortion of a sealed system depends on a lot more than the driver alone. The internal volume of the box has a major impact on low frequency distortion. The cone size, independent of the motor design, suspension parts, and internal volume, also influences distortion of the end product.
I'm aware, but compare the 18 to the 21... look at the 120db sweep.

RED



GREEN



Then if you want to compare output capabilities to lesser priced subs... the JTR 4000ULF ($3300) vs the Funk 21.0 ($6050) it's laughable...

notnyt is offline  
post #2813 of 4705 Old 05-20-2017, 02:59 PM
AVS Forum Special Member
 
Kain's Avatar
 
Join Date: Dec 2001
Location: Dubai, UAE
Posts: 4,187
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1933 Post(s)
Liked: 813
@notnyt

What's your opinion on having the side surrounds slightly in front of the MLP in a 7.1.4 setup? I might have to do this due to room limitations. Back surrounds will be where they should be (on the back wall).
Kain is offline  
post #2814 of 4705 Old 05-20-2017, 03:01 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by Kain View Post
@notnyt

What's your opinion on having the side surrounds slightly in front of the MLP in a 7.1.4 setup? I might have to do this due to room limitations. Back surrounds will be where they should be (on the back wall).
They're technically supposed to be directly to the sides to slightly behind, but if its only a little forward, I wouldn't worry.
notnyt is offline  
post #2815 of 4705 Old 05-20-2017, 05:40 PM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by notnyt View Post
I'm aware, but compare the 18 to the 21... look at the 120db sweep.

RED

GREEN


Then if you want to compare output capabilities to lesser priced subs... the JTR 4000ULF ($3300) vs the Funk 21.0 ($6050) it's laughable...
It is *very hard* to compare those distortion plots properly. The problem is that they are output normalized at one frequency, 50 Hz. The measurement with the 21.0 is using the internal amp, which probably uses DSP to boost the low-end. It's producing 3-4 dB more output below 20 Hz than the 18" is for curves that have the same 50 Hz response. That makes a big difference.

Second, going by product specs the internal volumes are very similar. The 21" cone has an inherent disadvantage with distortion measurements in the smaller box because the air spring exhibits more force for the same displacement and this characteristic disproportionately affects low (fundamental) vs. high (harmonic) frequencies. This is probably compensated for, at least partially, by a stronger motor in the 21.0 vs 18.0, but it still affects measured performance as moderate levels.

Of course, if you push them to their limits, the 21.0 will easily beat the 18.0 in total low frequency output by 2-3 dB because it has about 2-3 dB worth more overall displacement. This is confirmed by measurements of both CEA burst and long-term output.

Then there's the 21.0 LX, which uses a high Xmax, high motor strength under-hung driver, which is likely hard to beat for lowest distortion in small boxes. Of course, Josh Ricci hasn't measured one yet, so we'll have to wait and see how they look.

The only thing "funny" about your comparison between the JTR4000ULF and Funk 21.0 is the fact that they are two completely different kinds of subs. The original post concerned the need for *small* subs that fit in corners. IIRC, sealed 15s were being considered, and you bring a JTR4000ULF into the conversation?

Last edited by awediophile; 05-20-2017 at 06:01 PM.
awediophile is offline  
post #2816 of 4705 Old 05-20-2017, 05:57 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by awediophile View Post
It is *very hard* to compare those distortions properly. The problem is that they are output normalized at one frequency, 50 Hz. The measurement with the 21.0 is using the internal amp, which probably uses DSP to boost the low-end. It's producing 3-4 dB more output below 20 Hz than the 18" is for curves that have the same 50 Hz response. That makes a big difference.

Second, going by product specs the internal volumes are very similar. The 21" cone has an inherent disadvantage with distortion measurements in the smaller box because the air spring exhibits more force for the same displacement and this characteristic disproportionately affects low (fundamental) vs. high (harmonic) frequencies. This is probably compensated for, at least partially, by a stronger motor in the 21.0 vs 18.0, but it still affects measured performance as moderate levels.

Of course, if you push them to their limits, the 21.0 will easily beat the 18.0 in total low frequency output by 2-3 dB because it has about 2-3 dB worth more overall displacement. This is confirmed by measurements of both CEA burst and long-term output.

Then there's the 21.0 LX, which uses a high Xmax, high motor strength under-hung driver, which is likely hard to beat for lowest distortion in small boxes. Of course, Josh Ricci hasn't measured one yet, so we'll have to wait and see how they look.

The only thing "funny" about your comparison between the JTR4000ULF and Funk 21.0 is the fact that they are two completely different kinds of subs. The original post concerned the need for *small* subs that fit in corners. IIRC, sealed 15s were being considered, and you bring a JTR4000ULF into the conversation?

Both of the funk plots were run off the internal amp. The fact that the 18 had LOWER distortion at the same output level while being asked for more excursion and fed more power was the point.


If you follow along with the thread, funk was only mentioned in response to talking about seaton and jtr, hence the comparison while I was already on data-bass.
notnyt is offline  
post #2817 of 4705 Old 05-20-2017, 06:16 PM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Both of the funk plots were run off the internal amp [/QUOTE]

Sorry, you're right that both of those were run off the internal amp. However, Josh Ricci also measured the 18.0 using his own (more powerful) amp, which is labeled 18.0 (passive).

Quote:
Originally Posted by notnyt View Post
The fact that the 18 had LOWER distortion at the same output level while being asked for more excursion and fed more power was the point. If you follow along with the thread, funk was only mentioned in response to talking about seaton and jtr, hence the comparison while I was already on data-bass.
No! My point is that they weren't running at the same output level for those sweeps, *except* at 50 Hz, so the first bolded words are false. The part about more excursion on the 18" for the same output level is true. The part about the 18" being fed more power is un-comfirmed, at least until I look look carefully at the data. The larger cone of the 21" gives it an efficiency disadvantage with regard to small box at low frequencies, even though a larger cone (assuming equal mass and same motor Le, of course) is more efficient at high frequencies. In any case, the stronger motor in the FW21.0 driver may make up for some or all of the disadvantage of the cone size on low frequency efficiency.

Please re-read my post and this previous paragraph carefully and note that what I say about cone size and small sealed box efficiency is not widely well known. Indeed, I doubt most driver designers are aware of it. It's a conclusion I reached using careful mathematical analysis of the model problem, but it's born out in real world data. It is as I stated above, that a larger cone need more force to overcome the box air spring for the same volume displacement. If the driver otherwise has the same motor and suspension parts, this typically leads to higher Qtc for the larger cone, which leads to a response shape that amplifies harmonics relative to fundamental more than a lower Qtc response shape does.

Edit: Sorry, I meant Qtc not Qts here.

Last edited by awediophile; 05-20-2017 at 07:14 PM.
awediophile is offline  
post #2818 of 4705 Old 05-20-2017, 06:36 PM
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,197
Mentioned: 315 Post(s)
Tagged: 0 Thread(s)
Quoted: 3731 Post(s)
Liked: 3705
Quote:
Originally Posted by awediophile View Post

Sorry, you're right that both of those were run off the internal amp. However, Josh Ricci also measured the 18.0 using his own (more powerful) amp, which is labeled 18.0 (passive).

No! My point is that they weren't running at the same output level for those sweeps, *except* at 50 Hz, so the first bolded words are false. The part about more excursion on the 18" for the same output level is true. The part about the 18" being fed more power is un-comfirmed, at least until I look look carefully at the data. The larger cone of the 21" gives it an efficiency disadvantage with regard to small box at low frequencies, even though a larger cone (assuming equal mass and same motor Le, of course) is more efficient at high frequencies. In any case, the stronger motor in the FW21.0 driver may make up for some or all of the disadvantage of the cone size on low frequency efficiency.

Please re-read my post and this previous paragraph carefully and note that what I say about cone size and small sealed box efficiency is not widely well known. Indeed, I doubt most driver designers are aware of it. It's a conclusion I reached using careful mathematical analysis of the model problem, but it's born out in real world data. It is as I stated above, that a larger cone need more force to overcome the box air spring for the same volume displacement. If the driver otherwise has the same motor and suspension parts, this typically leads to higher Qts for the larger cone, which leads to a response shape that amplifies harmonics relative to fundamental more than a lower Qts response shape does.
You're right about the output levels not being the same, save for 50hz, however the rest is wrong for this comparison. I was looking at the max burst levels, which track very closely, instead of the response.

You can see the 18 is even less efficient at lower levels than the 21. There's anout 3db difference at 50hz, and about 7db difference at 20hz...




The UH21v1-D3 does look kind of nice, but I don't see it offered in any of their prebuilt subs. That's a driver I'd actually consider using, but the price is kind of silly.

Last edited by notnyt; 05-20-2017 at 06:44 PM.
notnyt is offline  
post #2819 of 4705 Old 05-20-2017, 06:49 PM
Member
 
jtwrace's Avatar
 
Join Date: Oct 2013
Location: Orlando, FL
Posts: 133
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Liked: 65
Quote:
Originally Posted by notnyt View Post

The UH21v1-D3 does look kind of nice, but I don't see it offered in any of their prebuilt subs. That's a driver I'd actually consider using, but the price is kind of silly.
Nathan just hasn't updated the website but that's what I got. The sub 21.0LX uses the UH21V1 driver. That's what I purchased (2) of to integrate with the my M2's.
jtwrace is offline  
post #2820 of 4705 Old 05-20-2017, 07:49 PM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by notnyt View Post
You're right about the output levels not being the same, save for 50hz, however the rest is wrong for this comparison. I was looking at the max burst levels, which track very closely, instead of the response.

You can see the 18 is even less efficient at lower levels than the 21. There's anout 3db difference at 50hz, and about 7db difference at 20hz...

No I can't. Both of those responses were measured with the internal amps and whatever internal processing they were configured with. The two systems may use different amounts of bass boost. What they do reveal is that the 21" is putting out 4 dB more @ 20 Hz and 8 dB more @ 10 Hz than the 18" is during the distortion sweeps that are normalized for the same level at 50 Hz. In your picture above, the difference at 50 Hz is < 3 dB. The differences at 20 Hz and 10 Hz are 7 dB and 11 dB, respectively. That's a *huge* difference.

Only the "FW18.0 (passive)" measurements, which were done with Josh's amp, show actual voltage sensitivity of the sealed sub + cabinet, without DSP. Then you have to adjust the voltage sensitivity data using impedance to get the actual power efficiency.

Quote:
Originally Posted by notnyt View Post
The UH21v1-D3 does look kind of nice, but I don't see it offered in any of their prebuilt subs. That's a driver I'd actually consider using, but the price is kind of silly.
I think Funk would sell them to you if you emailed him about it. You might have to wait a bit though. I won't argue that the price is on the high side.

I have four UH-21v1-D3. They work well for me because I had about 24" height to work with and not enough mounting depth to accommodate something like the Rockford Fosgate T3S-19. Subs using 18" drivers would be less capable in the same footprint. Less efficient 21" drivers would require even more than a single SpeakerPower SP2-12k to power to full excursion, and considering how much those amps cost, the price of the UH-21v1 didn't look so intimidating anymore. Indeed, no other driver on the market could give me as much low frequency output from within the space I have available than these could.

Overall though, I'd recommend subs from JTR, Seaton Sound, or Funk over what JBL has to offer. That's not to say that JBL subs are bad at all. And indeed, I'd have no trouble recommending Hsu Research, Power Sound Audio, SVS, or Rhythmic to most people. But seeing as this is a thread dedicated to what may be the "best speaker in the world" whose up-front cost is quite a bit higher than any of these budget brand subs, it only makes sense to recommend products from the top-tier, of which JTR, Seaton, and Funk are probably strongest, in my mind.
awediophile is offline  
Sponsored Links
Advertisement
 
Reply Speakers

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