Help with LMS Ultra 5400 Enclosure with "practical" LFE Extension - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #1 of 55 Old 04-25-2013, 05:41 AM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
I'm building a PR enclosure for an LMS Ultra 5400. I'm looking for the practical point of LFE extension without overly affecting other frequencies. I'd like to get the most LFE impact of movies like Tron Legacy, U-571, War of the Worlds, and King Kong etc. This is my first real subwoofer and I don't really have a frame of reference for what is sufficient SPL in the these frequencies. My room is likely going to reinforce frequencies only above 25 Hz, so the subwoofer needs to do all the LFE work.

Below are three enclosure variants I'm considering... Blue has the most at 20 Hz and the least at 10 Hz, while Yellow has the least at 20 Hz and the most at 10 Hz, with green in between. They're all the same in the middle around 14 Hz. I'll be using RoomEQ to flatten the in-room response with a FBQ2496, and to filter LFE frequencies to match driver excursion limits.

Blue: 8.125 ft3 tuned to 16.79 Hz with 3 PRs (+3dB@20Hz / -6dB@10Hz compared to Yellow)
Yellow: 8.125 ft3 tuned to 13.84 Hz with 2 PRs (-3dB@20Hz / +6dB@10Hz compared to Blue)
Green: 7 ft3 tuned to 14.85 Hz with 2 PRs (In Between)

When looking at the responses, is it better to give up some 20 Hz to get more 10 Hz content for the most impact in these types of these movies, or is it better to retain the 20 Hz region?

Thanks in advance.

Mr. Neverbicker is offline  
Sponsored Links
Advertisement
 
post #2 of 55 Old 04-25-2013, 07:27 AM
AVS Special Member
 
lukeamdman's Avatar
 
Join Date: May 2011
Location: Burnsville, MN
Posts: 1,274
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked: 96
Here a link to one I built:

http://www.avsforum.com/t/1338760/funky-waves-18-lms-5400-2-pr-build

Great sub with good efficiency!
lukeamdman is offline  
post #3 of 55 Old 04-25-2013, 09:49 AM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Thanks, I just read the thread.. I see you went all out for 20 Hz and nothing toward 10 Hz. I'm just concerned that by going all out at 20 Hz, I'd miss out on 10 to 14 Hz, which some movies can have a lot of. I've read that you don't know what you're missing until you dig into those frequencies. I see you did a quad sealed, which should hit hard at 10-14 Hz, albeit consuming a lot more power and costing lots more money than I have. I'll read that thread as well.

What I might do is build the enclosure for both the blue and yellow, by making the cabinet 8.25 ft3, and making a removable 3rd PR with a bolt on "plug" over the 3rd PR hole when operating with 2 PRs.
Mr. Neverbicker is offline  
post #4 of 55 Old 04-25-2013, 11:09 AM
AVS Special Member
 
lukeamdman's Avatar
 
Join Date: May 2011
Location: Burnsville, MN
Posts: 1,274
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked: 96
Quote:
Originally Posted by Mr. Neverbicker View Post

Thanks, I just read the thread.. I see you went all out for 20 Hz and nothing toward 10 Hz. I'm just concerned that by going all out at 20 Hz, I'd miss out on 10 to 14 Hz, which some movies can have a lot of. I've read that you don't know what you're missing until you dig into those frequencies. I see you did a quad sealed, which should hit hard at 10-14 Hz, albeit consuming a lot more power and costing lots more money than I have. I'll read that thread as well.

What I might do is build the enclosure for both the blue and yellow, by making the cabinet 8.25 ft3, and making a removable 3rd PR with a bolt on "plug" over the 3rd PR hole when operating with 2 PRs.

I think the final tuning frequency for the dual PR build was 17hz, so it was solid to 15hz or so.

In my room, anything under 14hz pretty much doesn't exist, even with quad sealed 5400s with 4kw each.

With my latest horns I'm back to that 16-17hz tune with solid output to 13-14hz. Losing that 10-13hz range really doesn't change anything for me in my room.

There are movies with 15-20hz bass, but the list of movies with bass near 10hz is way way less.
lukeamdman is offline  
post #5 of 55 Old 04-25-2013, 12:09 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Ah thanks for the very helpful info. Looks like I should shoot for 14+ Hz and not worry about anything below.
Mr. Neverbicker is offline  
post #6 of 55 Old 04-25-2013, 01:05 PM
Advanced Member
 
yelnatsch517's Avatar
 
Join Date: Nov 2006
Location: Los Angeles, CA
Posts: 980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
I don't understand PR builds. What is the allure for these? LMS 5400 PRs cost so much, wouldn't it be more better to just stick with 2 sealed 5400 builds?
Unless of course, you are like lukeamdman and absolutely don't need anything under a certain frequency.
yelnatsch517 is offline  
post #7 of 55 Old 04-25-2013, 01:32 PM
AVS Special Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: East side of NW Cascades
Posts: 2,601
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Liked: 304
Quote:
Originally Posted by lukeamdman View Post

In my room, anything under 14hz pretty much doesn't exist, even with quad sealed 5400s with 4kw each.
Losing that 10-13hz range really doesn't change anything for me in my room.

I get "usable" output to 12hz with just two sealed LMS-18's (6cubes) with 4kW each; and high woofer excursion down to 5hz (with less usability).
However I will say that a lot of the output at those frequencies are from harmonics, which is to be expected.

I could easily bottom out the LMS at any frequency at or below 30hz if I really wanted to (which I don't tongue.gif).

I don't run a high-pass filter (most of the time) and I'm boosting below 20hz by 6db and running the subs hot. Which usually isn't a problem, unless I'm listening to ULF-heavy bass music or movies at loud levels.

I went for the, extension with multiples, option.
BassThatHz is offline  
post #8 of 55 Old 04-25-2013, 01:33 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: AZ
Posts: 3,980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 102
Quote:
Originally Posted by yelnatsch517 View Post

I don't understand PR builds. What is the allure for these? LMS 5400 PRs cost so much, wouldn't it be more better to just stick with 2 sealed 5400 builds?
Unless of course, you are like lukeamdman and absolutely don't need anything under a certain frequency.

The allure is zero noise and compression compared to a port, along with not wasting any cabinet volume, and achieving very low tunes in relatively compact cabinets.

Value is definitely not there vs PVC pipe or a slot port. I jumped on my PRs when they were randomly on sale for 1/2 off.
Jay1 is offline  
post #9 of 55 Old 04-25-2013, 01:38 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
BassThatHz, do you feel that <14Hz is that beneficial for movies like Tron Legacy, U-571 etc?
Mr. Neverbicker is offline  
post #10 of 55 Old 04-25-2013, 02:32 PM
AVS Special Member
 
lukeamdman's Avatar
 
Join Date: May 2011
Location: Burnsville, MN
Posts: 1,274
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked: 96
Quote:
Originally Posted by Mr. Neverbicker View Post

BassThatHz, do you feel that <14Hz is that beneficial for movies like Tron Legacy, U-571 etc?

I'm not sure Tron dips down much below 20hz if at all. U-571 doesn't.

Also, just because my room has zip response below 14hz doesn't mean your won't either. You might have some nice room gain at that point, so tuning lower or going sealed might be well worth it. You have REW or other measurement software?
lukeamdman is offline  
post #11 of 55 Old 04-25-2013, 02:33 PM
AVS Special Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: East side of NW Cascades
Posts: 2,601
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Liked: 304
Quote:
Originally Posted by Jay1 View Post

not wasting any cabinet volume

I wouldn't say that, per se. PR's can take up quite the space when you factor in their mounting depth and required WxH.
The other disadvantage is that they produce lots of harmonic noise from all that moving mass that is trying to move and then trying to stop, in a non-linear way. Like a piano where all the strings are just a little bit off tune, in an unpredictable way.
Quote:
Originally Posted by Mr. Neverbicker View Post

BassThatHz, do you feel that <14Hz is that beneficial for movies like Tron Legacy, U-571 etc?

Yes it can be beneficial; and Yes it is a waste of money. It is also not worth trying unless you plan on running 4 or 8 subs and 2 or 4 amps.
I could live without it on movies and be happy.
But that never stopped us from trying, regardless. tongue.gif
BassThatHz is offline  
post #12 of 55 Old 04-25-2013, 02:45 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Got it. As far as PR vs ported, I'm open to doing either. I'm looking into it again and I may be able to fit the port in the room without too much hassle. I'm seeing a decent compromise in tube size that wouldn't be too large or noisy when tuning this to 15 Hz.
Mr. Neverbicker is offline  
post #13 of 55 Old 04-25-2013, 04:54 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: AZ
Posts: 3,980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 102
Quote:
Originally Posted by BassThatHz View Post

I wouldn't say that, per se. PR's can take up quite the space when you factor in their mounting depth and required WxH.
The other disadvantage is that they produce lots of harmonic noise from all that moving mass that is trying to move and then trying to stop, in a non-linear way. Like a piano where all the strings are just a little bit off tune, in an unpredictable way.
Yes it can be beneficial; and Yes it is a waste of money. It is also not worth trying unless you plan on running 4 or 8 subs and 2 or 4 amps.
I could live without it on movies and be happy.
But that never stopped us from trying, regardless. tongue.gif

A PR is a resonating mass, which is coupled to the enclosures air spring. This is functionally the same as the air inside of a port. What is this "harmonic noise" you speak of?

The volume eating by a PR is extremely negligible compared to a large long port
Jay1 is offline  
post #14 of 55 Old 04-25-2013, 04:55 PM
Advanced Member
 
cookieattk's Avatar
 
Join Date: Jun 2011
Posts: 524
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Liked: 56
http://aespeakers.com/shop/catalog/product_info.php?cPath=24&products_id=39 u could use some of these they will tune to more like 11 hz at 8cf and they cost 1/2 as much only draw back in how long he takes to ship orders i would contact them and ask for a firm date they could have them done by if u went with them . also psi makes pr

also
http://www.data-bass.com/data?page=content&id=82
cookieattk is online now  
post #15 of 55 Old 04-25-2013, 05:30 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
With low tuning, the ports get massive, but since the <15 Hz frequencies have to be attenuated to prevent over excursion, the port can be smaller without noise.
Mr. Neverbicker is offline  
post #16 of 55 Old 04-26-2013, 02:13 AM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
How well would this SPL response fill a 3000 cubic foot room?

Mr. Neverbicker is offline  
post #17 of 55 Old 04-26-2013, 04:51 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
I read through much of the Master List Bass Thread and see that the vast majority of bass is above 20 Hz, with some dipping down to 15 Hz, and very few under 15 Hz. I think I should be okay with optimizing for 15 Hz+. The lighting strikes in War of the Worlds hit down to 5 Hz, although the sound ranges well above 20 Hz, so there'd still be plenty impact I would think.
Mr. Neverbicker is offline  
post #18 of 55 Old 04-26-2013, 05:29 PM
AVS Special Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: East side of NW Cascades
Posts: 2,601
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Liked: 304
Quote:
Originally Posted by Mr. Neverbicker View Post

I read through much of the Master List Bass Thread and see that the vast majority of bass is above 20 Hz, with some dipping down to 15 Hz, and very few under 15 Hz. I think I should be okay with optimizing for 15 Hz+. The lighting strikes in War of the Worlds hit down to 5 Hz, although the sound ranges well above 20 Hz, so there'd still be plenty impact I would think.

That too. Beneficial but wasteful.
Quote:
Originally Posted by Jay1 View Post

A PR is a resonating mass, which is coupled to the enclosures air spring. This is functionally the same as the air inside of a port. What is this "harmonic noise" you speak of?
The volume eating by a PR is extremely negligible compared to a large long port

Have you ever tried pulling a bowling ball with a slinky before?
What happens when you pull a snow sled with a car and slam on the brakes? The kids crash into the car at 20mph, that's what.
It's a delayed reaction of the conversion of potential energy into kinetic energy.

It's 2 lbs undergoing 100 g-forces. When the signal stops or changes frequency that energy has to go somewhere. It goes back into the woofer(s) as a modulation (distortion).

The air has far less density and viscosity and frictional forces, it's more lossy, and thus damps faster than a moving-mass does.

It's easier to stop 100 Newton's of Air, than 100 Newton's of Lead, because the air will bend and deflect and give way. The lead won't. That's why shotguns shoot lead, not air.
BassThatHz is offline  
post #19 of 55 Old 04-26-2013, 05:34 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: AZ
Posts: 3,980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 102
It sounds like you formed an opinion based on how you think it works.

Link? Measurements?
Jay1 is offline  
post #20 of 55 Old 04-26-2013, 06:37 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
The PRs moving mass dampening is adjusted to be equivalent to the air compression dampening of a vent. I've read a lot that group delay is indicative of SQ, namely transient response, which doesn't vary according to vent vs PR.

Also, something about the AE PRs makes them more capable of lower frequency SPL than the VMPs, and they each consume just 0.05 cubic feet. However, PRs are still limited by excursion, whereas ports are not. Even with 3 PRs, there is still a portion of the max SPL clipped off when compared to ported with the same volume and tuning. When I carefully optimize the tuning, enclosure size, and vent size to the smallest vent volume possible without too much air flow noise, the same PR configuration is still 25% smaller overall. But then I found, at least with the LMS Ultra, that when tuned low enough, they become equal in overall size. Eight cubic feet tuned to 15 Hz consumes a net 10.6 cubic feet when adding vent volume. Equivalent response with PRs requires 3 PRs with the same net 10.6 volume, and would still have some of the response clipped due to PR excursion. So I'm probably just going to go ported with 8 cubic feet tuned to 15 Hz. Keep in mind, I'm carefully minimizing the port volume by keeping the air flow around 20 m/s at 116db@20Hz, and around 35 m/s at 120db@20Hz, assuming the higher air speed would still remain inaudible when the sub is hitting louder.
Mr. Neverbicker is offline  
post #21 of 55 Old 04-26-2013, 06:44 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: AZ
Posts: 3,980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 102
While it's easy to see when the pr output compresses, the models wont show port compression. That's going to be your only real variable.
Jay1 is offline  
post #22 of 55 Old 04-26-2013, 07:41 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
It was my understanding that the moving mass of the PR becomes the equivalent of the compression of the air in the port, but I could be incorrect about this. In any event, I don't think the PR begins to lose some response due to compression, but instead due to excursion limit.

My real question at this point is how much SPL @20Hz should I be giving up to get more LFE output considering I'd like it to be loud in a 3000 cubic foot room. I have no direct experience to know what I'd like the SPL to be in the audible range. I'm not talking about house damaging loud by any means. I just don't want to sacrifice too much in the audible range, and I don't know how much is enough for a really engaging experience. How much SPL should I be shooting for at 20 Hz to get that kind of sound in a 3000 cubic foot room?
Mr. Neverbicker is offline  
post #23 of 55 Old 04-26-2013, 08:12 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: AZ
Posts: 3,980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 102
Quote:
Originally Posted by Mr. Neverbicker View Post

, I don't think the PR begins to lose some response due to compression, but instead due to excursion limit.

Yes, this is what I was referring to with PR compression. It is compression of the signal when the PR stops contributing to the systems output.

It's really going to be hard to say what you need when you dont know what you need tongue.gif One rarely mentioned benefit to a PR system is the ability to change the tuning point. You could start out with the 15hz setup, and remove mass for more output higher up to compare with little effort. Of course, thats a lot of extra money for that option.
Jay1 is offline  
post #24 of 55 Old 04-26-2013, 09:35 PM
Advanced Member
 
yelnatsch517's Avatar
 
Join Date: Nov 2006
Location: Los Angeles, CA
Posts: 980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
Doesn't unibox show everything or are the graphs in unibox not very accurate?
yelnatsch517 is offline  
post #25 of 55 Old 04-26-2013, 09:49 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Unibox matches very well with WinISD with what I've tried so far. As Jay1 said, It's really going to be hard to say what I need when I don't know what I need. I'm reading around trying to get an idea of how much subwoofer SPL I should be shooting for.

EDIT: I'm a dunce! I just realized I have room gain backwards, so this changes things. Notwithstanding nodes, room gain boosts the lower frequencies. Duh! I should be getting in room gain starting around 25 Hz or so. I do have tons of sporadic wideband absorption which should help smooth things out before EQ.
Mr. Neverbicker is offline  
post #26 of 55 Old 04-27-2013, 12:49 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Quote:
Originally Posted by lukeamdman View Post

I think the final tuning frequency for the dual PR build was 17hz, so it was solid to 15hz or so.

In my room, anything under 14hz pretty much doesn't exist, even with quad sealed 5400s with 4kw each.

With my latest horns I'm back to that 16-17hz tune with solid output to 13-14hz. Losing that 10-13hz range really doesn't change anything for me in my room.

There are movies with 15-20hz bass, but the list of movies with bass near 10hz is way way less.

If you're not noticing under 14 Hz with the quad sealed 5400s with 4kw each, there's no point in tuning that low with a single bass reflex because it still wouldn't come close to the quad sealed under 14 Hz.. I'll just tune to 16 Hz. I'm sure this will give me more than enough SPL. I just want to be able to hear the entire dynamic range of movies as recorded, and maybe a touch extra for good measure.

Thanks for the help everyone.. I'll post how well this meets my expectations, one way or the other.
Mr. Neverbicker is offline  
post #27 of 55 Old 04-27-2013, 09:48 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Something's very wrong with the LMS spec... two issues actually.

The port lengths for a given tune on the TC Sounds website (Enclosures Tab) are much longer than in WindISD and Unibox. For instance when tuning to 15 Hz with an 8 cubic foot enclosure, the website calls for a 6"x4" port 90" long. WinISD and Unibox call for the same port to be just 31.69" long. That's 1/3 the port length. Am I doing something wrong or is the website completely wrong?

Also, I've read here that the maximum excursion for the LMS Ultra 5400 is the exact same as it's xmax at 33.655mm, so there's no room for pushing it beyond linear. Yet the website list 70% BL at 38mm, and Xmech at 44mm.

This is extremely frustrating.
Mr. Neverbicker is offline  
post #28 of 55 Old 04-27-2013, 10:50 PM
AVS Special Member
 
audiovideoholic's Avatar
 
Join Date: Mar 2008
Location: Murray KY
Posts: 2,297
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Liked: 50
^
I've posted this before but.....

NOT member posted his test results that the xmax/mech was a little shy of TC specs if I'm not mistaken. I remember his tests and there was more to it than just the xmax and how he would have made smaller enclosures since had to modify them from the DEAD Mal 18s he went through.

Pretty sure you can search his build and find the xmax results pretty easy as it was a big convo in his thread.

Sorry cant comment on anything else but having correct xmax will still help when modeling.

Edit.
Disregard the man behind this post as I now see you linked exactly what I was talking about. Wasted 1 minute of each readers time that didnt click "here" in the post above biggrin.gif
audiovideoholic is offline  
post #29 of 55 Old 04-27-2013, 11:56 PM - Thread Starter
Member
 
Mr. Neverbicker's Avatar
 
Join Date: Feb 2011
Posts: 166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Thanks. I'll start bolding and underlining links. Yes I do read up until I run into a dead end before posting questions. I'd have to believe the guy that basically the LMS is linear to xmax with absolutely no room for more excursion.

I also found a post that the port specs on the enclosures listed on the TC website are way off. I gotta say for this caliber of driver, TC should have gotten these two specs right before publishing.

Back to ported versus PR for this driver.. I read up some more about port compression and now I better understand what Jay1 was saying. It's a loss that passives don't have, and not accounted for in SPL graphs. I'd wager that port compression at higher SPL is a fair trade for a passive's transition from linear at higher SPL.

I just might be underestimating the passive. I'm wondering if I should be entering the passive's one-way excursion for xmax in WinISD/Unibox to fairly compare against port compression. With this in mind, what is a safe maximum non-linear xmax I could use for the PSI passive and the AE passive? (PSI lists 3.5" usable excursion and AE lists 3" peak to peak)
Mr. Neverbicker is offline  
post #30 of 55 Old 04-29-2013, 10:35 AM
AVS Special Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: East side of NW Cascades
Posts: 2,601
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Liked: 304
The LMS has about 3.1 inches of excursion before bad things happen.



This here is as far as I usually push the LMS, because it starts to get very mechanically non-linear beyond this point (heavily distorted).
BassThatHz is offline  
Reply DIY Speakers and Subs

User Tag List

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