+ Reply to Thread
Results 1 to 14 of 14

Thread: Effect of enclosure. . . .

  1. #1
    Dis Member mikebake's Avatar
    Join Date
    Apr 2003
    Location
    Lima, Ohio, USA
    Posts
    2,623

    Effect of enclosure. . . .

    I'm trying hard not to have this be a "well, DUH!" kinda post, but I gotta say that it is still amazing to me how much we are listening to the BOX, as opposed to the driver. Okay, I know that is why they call it a system, and that is why we spend so much time talking about the all-important cabinet and it's construction, but STILL, I have to remind myself how much of the character of the sound is determined by the box.

    I think that many peoples perceptions, even those who have been into audio for quite some time but perhaps never done any DIY or component swapping, is to underappreciate what role the enclosure has.

    Okay, so you start with a driver with certain parameters, which then tend to suggest the best enclosure alignment/type, and then work within the practical restraints to build such an enclosure. Or you you work the other way, starting with a favored enclosure design and seeking drivers that work well within. Basic stuff, I know.

    The point I have been pondering is how far some manufacturers go to (at least brag of) create a "resonance free" box. I'm all for inertness, at least that is what I have been told I should want, but I wonder how far we want to really go in that direction.
    There seems to be some efforts that go to ridiculous and expensive lengths. (Again, many people have to be educated about the labor costs of constructing a proper enclosure, and how much of the price of the final product resides in the cabinet). So how important is it, and where is the point of diminishing returns? (some drivers probably wouldn't even sound good without box coloration!!)

    Most large format JBL monitor cabs, for example, are nice heavy beasts, well constructed, but not slaves to the nth degree of inertness.

    Give me a really good driver and a reasonably constructed box.

    So, from whence came the epiphany?
    I, like many of you, have taken a mainstream driver, in this case a 2226, and listened to it in direct comparison with 5-6 different configurations;
    a)front loaded horn, (still a nice sound)
    b)a 3 cu ft direct radiator, ported
    c) a 6 cu ft direct radiator, ported
    d) a 23.5 cu ft direct radiator, ported, multiple drivers
    e) 3.5 cu ft sealed
    f) rear loaded scoop
    g)probably a few I have forgotten

    Every time, I shake my head and say "it's the damn BOX; to hell with the driver, we're hardly listening to it!" An exaggeration, of course, but it seems like the truth.

    There are some corollaries that emerge, and some drivers do perform better in a wider variety of enclosures than others, but IT'S THE DAMN BOX!!
    Some of YOUR thoughts?


    Okay, I'm done.


    Except for infinite baffle....................

    Last edited by mikebake; 04-19-2004 at 06:54 PM.

  2. #2
    RIP 2009
    Join Date
    Feb 2004
    Location
    Rohnert Park, CA
    Posts
    3,790
    So which box did you prefer?

    John

  3. #3
    Dis Member mikebake's Avatar
    Join Date
    Apr 2003
    Location
    Lima, Ohio, USA
    Posts
    2,623
    It depends, of course, on the application. Overall I prefer fully horn loaded systems, at least from 80 hz and up, and lower if the real estate allows.
    Two words keep coming back about horns......power and control, power and control...................

  4. #4
    Junior Member gonefishin's Avatar
    Join Date
    Sep 2003
    Location
    Joliet, Illinois
    Posts
    14
    Hi Mike,


    What a cool experiment!


    Even tho I have listened to various enclosures. I haven't set anything like this up...where the same driver was used in ALL enclosures.

    What did you use for the crossover? (I'm just guessing an active)


    Was it set the same for each of the enclosures...or did you adjust it to "suit" each.

    Did you perform this test with NO midrange driver/horn? (or did you have the midHorn also hooked up, to see how each "matched" up with the midrange)


    Could you give some more thoughts on YOUR description of each enclosure?

    I may be building some new boxes for some 416's...it would be great to go Horn loaded...but I'm not sure if the room is large enough (this will be my brothers pair of speakers...not mine)


    ...I'd love to hear your thoughts!


    thanks, dan
    Last edited by gonefishin; 05-06-2004 at 01:04 PM.

  5. #5
    Senior Member
    Join Date
    Jan 2004
    Location
    Pensacola, Florida
    Posts
    131

    ABC’s …

    … of Loudspeaker Design

    MB,

    Some notes in brief follow:

    a) It is only the performance that is worthy of a ‘listen’, nothing else. If the focus is not there, then something is wrong and needs fixing.

    b) The enclosure (‘box’) can be no better than the driver you put in it. Some enclosures degrade driver performance while others enhance it. All enclosures perform a baffle function the specifics of which are determined principally by the driver(s) used.

    c) A good loudspeaker system design is dependant on the marriage of four things that are determined entirely by the venue in which they are used:

    1) The driver(s)
    2) The enclosure
    3) The crossover/equalizer
    4) The power amplifier(s)

    d) There other constraints imposed on loudspeaker design that have nothing to do with the Acoustics of the matter. They are related to the market (venue) forces that are mostly based on economics.

    e) The hardest to design, is a good, cheap loudspeaker system. By comparison, design of an expensive one is a ‘cake-walk’.

    Regards,

    WHG

  6. #6
    Dis Member mikebake's Avatar
    Join Date
    Apr 2003
    Location
    Lima, Ohio, USA
    Posts
    2,623
    Originally posted by gonefishin
    Hi Mike,


    What a cool experiment!


    Even tho I have listened to various enclosures. I haven't set anything like this up...where the same driver was used in ALL enclosures.

    What did you use for the crossover? (I'm just guessing an active)


    Was it set the same for each of the enclosures...or did you adjust it to "suit" each.

    Did you perform this test with NO midrange driver/horn? (or did you have the midHorn also hooked up, to see how each "matched" up with the midrange)


    Could you give some more thoughts on YOUR description of each enclosure?

    I may be building some new boxes for some 416's...it would be great to go Horn loaded...but I'm not sure if the room is large enough (this will be my brothers pair of speakers...not mine)


    ...I'd love to hear your thoughts!


    thanks, dan
    Hi Dan;
    About the crossovers; I have listened to them in each box with both active and passive. (except the 23.5 cu footer), and with and without the accompanying mid/hi drivers.
    As for adjusting the crossover, in the front horn I have run them as two way up to 1200, and as three way to about 440 hz, ans sometime with some cut around 220 and a bit of boost below 60.
    In the 3 cu ft, a two way run again to 1200, and in the 6 cu ft as a three way run to about 380. In the big box they were filtered below 30 hz and rolled out about 280. In the scoop they were run as subs and rolled out, if I recall, about 220hz.
    Concerning the 416's, there certainly is a bunch of experience out there with them, but other than having heard them a good bit, I haven't owned any to mess around with. Some people swear by their sound, but don't expect much deep out of them. It DOES seem like the newer, higher power handling 15's like the 2226 don't come into their own until you push them a little, unlike the older variants, and apprently give up some transient response to boot.
    Still a good driver, though.
    Horn designer Bill Woods, who works for a company building pro sound speakers, has designed and is building a very interesting, thick conical aluminum horn (on his own, not for the company he works for) that looks to make a very nice midrange horn. I think I may look into them at some point.
    From an email he sent me.

    Yes It will work on any driver from 2" on down to a .625" ( 555w) Driver.
    Since this a conical horn, the wavefront is never curved by the horn as in
    an exponential. Since there are no slits. or mis-shaping the wavefront- the
    wave is always in phase until the first breakup mode of the driver. it does
    not have that "horn like" sound, which is in part caused by non- straight
    horns.
    The mouth size sets the low cutoff frequency. The throat size sets the upper
    cut off frequency.

    The AH! 700 has a 60 degree pattern and is very smooth on and off axis. the
    mouth size was set to capture 900Hz and up to match the articulation of
    human speech. As a result it has a ver clear lifelike sound.

    The design is made so it can be bolted in, or sit on top of the bass
    enclosure- kind of like a sculpture thus it does not appear humongous in a
    living room.

    It will be sold as a finished unit with stand, or the raw horn with the O.D. of
    the throat ready for a flange. the customer would have it sand blasted and
    make a throat of choice. The price will be from $400.00 to $750.00 US$ each
    depending on model.
    Each horn will come with a schematic for the intended driver and curves.

    All of this will be on a website as soon as I can get it up and running.
    Hope this helps, Bill

    PS Jonathan just got the first two- you can talk to him about his
    impressions of the sound.

    Best, Bill

    Sounds interesting, eh Dan?? Supposed to give all the other home audio mid horns a real run for the money.
    MBB

  7. #7
    Dis Member mikebake's Avatar
    Join Date
    Apr 2003
    Location
    Lima, Ohio, USA
    Posts
    2,623

    Re: ABC’s …

    Originally posted by whgeiger
    … of Loudspeaker Design

    MB,

    Some notes in brief follow:

    a) It is only the performance that is worthy of a ‘listen’, nothing else. If the focus is not there, then something is wrong and needs fixing.

    b) The enclosure (‘box’) can be no better than the driver you put in it. Some enclosures degrade driver performance while others enhance it. All enclosures perform a baffle function the specifics of which are determined principally by the driver(s) used.

    c) A good loudspeaker system design is dependant on the marriage of four things that are determined entirely by the venue in which they are used:

    1) The driver(s)
    2) The enclosure
    3) The crossover/equalizer
    4) The power amplifier(s)

    d) There other constraints imposed on loudspeaker design that have nothing to do with the Acoustics of the matter. They are related to the market (venue) forces that are mostly based on economics.

    e) The hardest to design, is a good, cheap loudspeaker system. By comparison, design of an expensive one is a ‘cake-walk’.

    Regards,

    WHG
    Hi Bill, thanks for the reply.

    a) right!
    b) yeah, I wasn't contemplating the baffle function as much as I should. I understand the effect, but have only absorbed a few conclusions, and not the math preceding it.
    c) My conclusions have been that many people underappreciate the costs involved in delivering a very good enclosure and underestimate the percentage of the final price that the cabinet represents. Ditto for the crossover, but much of the $ here seems to be in paying for the brainpower to design and test and refine. I'm told that the crossover is the hardest aspect to get right and is where success often lies, or fails.
    d) and the resulting interesting tradeoffs that people make in their designs
    e) great point, and apparently why some many DIY guys have a ball pursuing it. I have heard some really nifty CHEAP systems, but actually if you figure in how much time and learning and thought are behind some of these DIY'ers, the money is in their knowledge and not always the materials.
    Thanks again for your reply, I always enjoy your pithy replies.
    Last edited by mikebake; 05-10-2004 at 09:01 AM.

  8. #8
    Junior Member
    Join Date
    Apr 2004
    Location
    Bellingham, WA
    Posts
    10
    You might be surprised how low that 416 will go in the right enclosure. It was known as a combination woofer, working in both a bass reflex and a horn loaded system. I have had both the 416 (of course) as well as the JBL (15" 2526 J- did I correctly recall the model?) and my perception (though I did not a/b them or check specs was the 416 had more bottom end.

  9. #9
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    8,499
    I think you mean the JBL 2226J. It is a fine woofer for upper bass and low mids but it will not produce deep bass unless several are used per channel and there is both room gain and added EQ.

    The Altec 416 is used in the Model 19. In that bass reflex cabinet it produces lower bass than the 2226 typically does, but it could still use the help of a subwoofer if you are trying to reproduce the bottom end of contemporary recordings.

  10. #10
    Dis Member mikebake's Avatar
    Join Date
    Apr 2003
    Location
    Lima, Ohio, USA
    Posts
    2,623
    Originally posted by Mr. Widget
    I think you mean the JBL 2226J. It is a fine woofer for upper bass and low mids but it will not produce deep bass unless several are used per channel and there is both room gain and added EQ.
    Probably semantics here, but without EQ and minimal room gain, I get response from about 40-45 hz and up in a 6 ft vented cab from the 2226. They're decent if asked to do midrange duty, but I'd rather not hear them above about 380hz.

    http://www.jblpro.com/pub/obsolete/venue/vs3115.pdf

  11. #11
    Webmaster Don McRitchie's Avatar
    Join Date
    Apr 2003
    Location
    Winnipeg, Canada
    Posts
    2,040
    Now that I have a pair of Model 19's, my experience is that the 416 will get down relatively flat to the mid 40's but rolls off after that. I have mine eq'd with 4db gain centered at 40hz which seems to give reasonable bass response. However, it would definitiely benefit from a sub.
    Regards

    Don McRitchie

  12. #12
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    8,499
    Originally posted by mikebake
    Probably semantics here, but without EQ and minimal room gain, I get response from about 40-45 hz and up in a 6 ft vented cab from the 2226. They're decent if asked to do midrange duty, but I'd rather not hear them above about 380hz.

    I think we are saying the same thing. Some people are happy with 40Hz as the low end of a system. If you listen primarily to music recorded in the mid 70's and earlier, that is probably all you need. Contemporary music, though has significant content to 30Hz and below. I am not talking about the stuff you hear driving down the street either. Contemporary Jazz and Rock have significant amounts of deep bass that was not recorded a few decades ago.

    Widget

  13. #13
    Senior Member Steve Schell's Avatar
    Join Date
    Jun 2003
    Location
    Long Beach, CA
    Posts
    1,426
    Hi Mike,

    Getting back to your original post, I think it is important to make one distinction. In a bass reflex box, the volume of air in the box in combination with the port area will resonate at a certain frequency. The goal, at least in early designs, was to tune the box to resonate at the same frequency as the cone resonance. These two bodies resonating out of phase would cancel one another, turning one huge impedance peak into two smaller ones, smoothing and extending system response. There is a lot of resonatin' goin' on here, but it is entirely proper and key to the design. In the late 1930s, Jim Lansing referred to his enclosure for the Lansing Iconic as a "resonated baffle."

    Enclosure panel resonances are another thing entirely, and few would argue that they are detrimental and best avoided to the extent possible- brace it, fill it with sand, pour it from concrete!

    I have seen horns referred to as "broadband resonators". Hmmm, don't like the sound of that much.

  14. #14
    Dis Member mikebake's Avatar
    Join Date
    Apr 2003
    Location
    Lima, Ohio, USA
    Posts
    2,623
    Originally posted by Mr. Widget
    I think we are saying the same thing. Some people are happy with 40Hz as the low end of a system. If you listen primarily to music recorded in the mid 70's and earlier, that is probably all you need. Contemporary music, though has significant content to 30Hz and below. I am not talking about the stuff you hear driving down the street either. Contemporary Jazz and Rock have significant amounts of deep bass that was not recorded a few decades ago.

    Widget
    I've not really measured in room response for a 2226 system, bujt figured room gain is helping me; that, and I've been running two 2245's lately, and they give me the bottom.
    Anyway, it is suprising what is below 45 on some recordings. Most of the stuff I'm listening to has been recorded in the last 15 years.
    Tonight I am working on another bastard rig scenario. It'll probabably take a few days to sort out. I moved most of the crap out of the workshop into the garage, and am putting an old loveseat in the workshop for warm weather listening.
    I'm going to go three way horn, and then to one 28 cu ft box in summed mono with four 2226's for the sub. The efficiency of the lowest unit is 103db and goes up from there. Fun. The midbass and higher horns can run a little freer now! Photo soon, perhaps.
    Last edited by mikebake; 05-11-2004 at 05:16 PM.

+ Reply to Thread

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. JBL Enclosure Plans
    By boputnam in forum Lansing Product Technical Help
    Replies: 5
    Last Post: 02-09-2014, 01:23 AM
  2. Double Woofers in Single Enclosure Question
    By stevem in forum Lansing Product Technical Help
    Replies: 9
    Last Post: 12-02-2004, 09:37 PM
  3. JBL 1500 Sub enclosure
    By Tom Loizeaux in forum Lansing Product DIY Forum
    Replies: 10
    Last Post: 04-30-2004, 07:38 AM
  4. C37 as a Subwoof Enclosure
    By John Y. in forum Lansing Product DIY Forum
    Replies: 5
    Last Post: 06-03-2003, 11:35 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts