Professional Concert Loudpseakers

Discussion in 'Home Theater Projects' started by Matthew Will, Dec 16, 2003.

  1. Matthew Will

    Matthew Will Stunt Coordinator

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    Hello,
    I'm interested in Hometheater obvisously but I am really interested in Professional loudspeakers. Here are my questions.
    1. What is the difference between the build of a speaker they use at a concert and one you find in your home theater? I am talking about the actual speaker itself, not the enclosure. Are professional speakers beefier? Are speakers like the Adire Audio Tempest worthy of being a concert loudspeaker?
    2. What is the difference between enclosure design of a concert loudspeaker and one found in a home theater?
    3. How do concert systems produce the high frequencies? If the concert is a sold out 60,000 seat stadium I doubt they will be using 1" tweeters to produce high frequencies. If they use 4" or 5" speakers then how do they get them so loud without distorting and eventually destroying them?
    4. What would be my first step towards DIYing my own concert style loudspeaker system?

    It's hard to say what I am asking. Are these systems that are just ridiculously loud? I'm not sure. Someone help. Thanks. Matt
     
  2. Brett DiMichele

    Brett DiMichele Producer

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    Matt,

    Concert speakers are designed for longevity and SPL output
    but not always "accuracy" across the frequency range.
    Consider that most of this stuff is used for Rock Concerts
    where they just pump the bass and trebbel to ear bleeding
    levels.

    How do they get longevity? PA/Concert drivers rarely have
    the amounts of excursion that home drivers do. So in that
    respect a good home sub woofer for example is usually built
    to take more punishment than a PA Low Frequency Driver.

    They get the output by using either Folded Bass Horns and
    Horn Loaded Tweeters (JBL, Selenium etc.) which all cost a
    fair amount of change.

    [​IMG]
    This is an example of a JBL Compression Horn Driver and the
    cost is $490.00 each. Then you have to add a Horn Throat
    onto the compression driver:

    [​IMG]
    JBL Bi-Radial Compression Horn Throat $279.50 each..

    And then you need a good set of low frequency drivers like
    a set of Eminence Lab12's that need to be Horn Loaded as
    well. The enclosures are some of the most complicated to
    build..

    These items "can" be made into a home theater/home audio
    version that can yeild accurate sound but the concert stuff
    rarely does.. Most concert low frequency drivers don't even
    play below 30-40Hz... In a good HT you would tune a sub as
    low as 17Hz..
     
  3. Joseph Sabato

    Joseph Sabato Stunt Coordinator

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    I agree with what Brett said but I understand what you might like about concert systems. BTW, Movie Theatres pretty much use horn loaded drivers across the board too, and for the same reason.

    Find yourself a local Klipsch dealer and ask to hear the RF7,RC7 and RS7 HT system (This is the Reference Series, not the Synergy Series that Best Buy carries), this will get you pretty close to what you are looking for. They are very dynamic, will play very loud with low distortion and are pretty accurate to boot. They usually have a sub with this system, but the RF7 towers go fairly low on their own, it depends on how much of a bass head you are ( I would want the sub!)
     
  4. Allen Ross

    Allen Ross Supporting Actor

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    One thing that i have to disagree on with Brett is, the LF drivers, sure they aren't going to be pushing 30mm xmax but what they do have that no HT sub i have seen is Amazing sensitivity.

    Take the tempest as an example okay we all know its a kick as HT sub that loves to be played at 16-20 hz, its SPL is 89 w/m. Now take SELENIUM 15SW1P-SLF, its a 15 PA sound reinforcement loud speaker, it can handle 800 watts RMS, and at 96 db w/m meaning that you would need to give the tempest 4 times the power as that Selenium in order to reach the same levels.

    Also if you have a Tempest of any such DIY HT sub, play some rock music, turn it up real loud, does it hit you in the chest? not really, now play a 20 hz sine wave, it doesn't hit you in the chest but it sure as hell shakes the house down. Now in any given concert when they hit that bass drum you feel it in your chest, it hits you hard. why is that? group delay, and the tightness of the driver, the tempest can hit low but has almost ungodly bad group delay, mine it upwards of 25ms, around 30 you will start to notice it, now that Selenium's group delay won't even come close to that more on the order of 8-10 ms, resulting in a very tight and chest slamming driver.

    If you want to see some PA sytle designs head over to parts express and look up Selenium and with any of their drivers they have a slew of sugested alignments where some range from two 18 subs, two 12 mid bass and one 440 Ti which is a massive 2" compression driver thats 9 inches around an weighs is much as a tempest [​IMG]

    As for sound quality, i think you can make one hell of a kick ass speaker that will sound phenomenal, and will break 120 db, granted it won't have supper amazing detail, such as the AV-3's but if done correctly you can get amazing dispersion and a pretty flat response thats just made to play loud, and slap you around while at it.
     
  5. Brett DiMichele

    Brett DiMichele Producer

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    Allen,

    While I do agree completely about the sensitivity that is
    generaly due to the materials used in the PA Drivers. If
    you look at most "pro" LF drivers they have very low Xmax
    Limits and usually use an Accordian Cloth or other low loss
    surround since they don't need as much suspension as the
    higher excursion driver. Likewise the pro drivers rarely
    play what HT buffs consider "Low Frequency" and they don't
    need nearly as stiff of a cone and that's why you usually
    see simple treated papers which weigh less.

    Group Delay isn't the reason the Pro Venue LF drivers "HIT"
    you hard in the chest it's simply because they are tuned
    way higher.. I would assume most pro LF setups are tuned to
    30Hz if not higher.. And that is where you get "Slam"..
     
  6. Jason_Me

    Jason_Me Stunt Coordinator

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  7. Mike Keith

    Mike Keith Second Unit

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    Also one other main difference is the Crossovers, a pro speaker stack almost never has any passive crossovers of any kind, all Active. No power wasted with active and that’s where some of the hit comes from, much better dampening between the amp and speaker.
     
  8. Matthew Will

    Matthew Will Stunt Coordinator

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    Here are some more questions

    1. Does the loudspeaker design cookbook talk about PA style designs or is it mainly for car audio and home theater?
    2. How do the PA style woofers produce higher SPL if their xmax is smaller?
    3. How do I know which design will produce the most insane bass? Something tells me I would be a lot more impressed with my home stereo/theater system if it can hit 120-125 db's than it hitting 20 Hz and below. Hell, if I get crazy and build several enclosures stacked with 18's and I hit 130 that would be some serious kick ass.
    4. Would the selenium drivers be comparable in quality to adireaudio products? When I go to partsexpress.com I just get the feeling that the products may be decent but not great. They remind me of what JC Whitney is for cars. Not the best product quality but good enough to last.
    5. Any other suggestions? Maybe answer some typical questions I'm forgettin? I dunno. Matt
     
  9. Brett DiMichele

    Brett DiMichele Producer

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    1. Does the loudspeaker design cookbook talk about PA style designs or is it mainly for car audio and home theater?

    Not sure...

    2. How do the PA style woofers produce higher SPL if their xmax is smaller?

    Higher Tuning requires less excursion and Horn Loading increases
    the SPL Output.


    3. How do I know which design will produce the most insane bass? Something tells me I would be a lot more impressed with my home stereo/theater system if it can hit 120-125 db's than it hitting 20 Hz and below. Hell, if I get crazy and build several enclosures stacked with 18's and I hit 130 that would be some serious kick ass.

    If you want insane output in the 30-40Hz region that's easy
    with a Folded Horn.

    4. Would the selenium drivers be comparable in quality to adireaudio products? When I go to partsexpress.com I just get the feeling that the products may be decent but not great. They remind me of what JC Whitney is for cars. Not the best product quality but good enough to last.

    PE is nothing like JC Whitney. PE carries the best Pro Sound
    and Home Drivers and Selenium, JBL are two of the best in
    the business.


    5. Any other suggestions? Maybe answer some typical questions I'm forgettin? I dunno. Matt

    Someone else may be of more help here.. I am sure others
    will chime in. But I can tell you this much. You are choosing
    one of the hardest designs for a DIY person to make. Folded
    Bass Horns and Horn Loaded Midrange and Tweeters are some of
    the most complex setups there are.. Some guys choose to make
    thier own Horn Lenses for the Midrange and Tweeters this
    requires a Lathe and precision measuring instruments as well
    as lots of wood working knowledge. You need to speak with
    the guys who have "been there done that" with horns.
     
  10. Allen Ross

    Allen Ross Supporting Actor

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    Brett

    if you break a signal in the LF region down into fourier components and look at the phase plot of the speaker's transferfunction, and extrapulate the time delay curve, then you see these Forier comenents aren't produced at the same instance in the time domain, and thus: they don't superimpose properly to give you the same signal, with the same dynamics as the input.

    Sound reinforment speakers are tuned higher- theres no getting around that- however the argument that tuning a speaker higher gives better "punch" seems to break down, i believe- because as as the tuning frequency gets lower, and lower- the response approaches that of a sealed speaker of the same volume, and we all know 2nd order (sealed) loading has better delay response and has a characteristic tight punch.
     
  11. Brett DiMichele

    Brett DiMichele Producer

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    Allen,

    I understand and agree with what you state about group dely
    and it's importance on the accuracy of the reproduced signal.

    I am just "adding" that the higher tuning produces more
    output in the octaves that produce what we refer to as "punch"
    Kickdrums, Bass Guitar etc. That's all 30-40Hz information
    and those are the instruments generally refered to as having
    "Punch" associated with them.
     
  12. Dave Milne

    Dave Milne Supporting Actor

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    Matt,
    How large is your room? If you are trying to achieve "concert" levels outdoors or in a large venue (>5000 cu.ft.), then, yes, you will need to resort to pro gear. However, you can achieve "insane" levels in a typical listening room with normal home equipment. For example, my DIY mains with Dynaudio drivers are roughly 91dB @ 1 watt/1meter. With 400W (Bryston 4BST @ 4 ohms) each will put out 117dB. A closely-coupled pair would theoretically put out 123dB.
    [​IMG]
    True, the inverse square law suggests that you lose 6dB with each doubling of distance... but the room tends to compensate for this. So overall, they are still able to achieve 115dB+ peaks in my 3000 cu ft. listening room. This is as loud as any concert, and louder than I ever care to listen, except for brief blow-your-socks-off demos. If you want even more, you can look into the line arrays discussed at length in this forum. A pair of the GR Research LA's, fed with, say, Bryston's 7BSST monoblocks (~1KW) and you're well into ear-bleed territory.
     
  13. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I think that pro audio speakers have different design issues. One is wide dispersion to cover a larger "sweet spot". This can actually be a bad thing in a home when a single person wants to listen although there are some omnipolar speakers that come to mind. (ick) Another difference is how loud they are meant to play. Home speakers are in a small room and situated near the listener while pro audio speakers must play long distances and sometimes in open air. So since the listening position is closer, I believe it is easier for home speakers to have better sound quality at the same volume level.

    I think enclosures are heavy duty for touring speakers while home speakers have more aesthetics in mind. Size is also an issue since most pro audio speakers can be big. Home speakers can have more detail involved such as spikes, adjusting the toe-in, x-y distances, etc. all for a single listening spot while pro audio is adjusting the speakers to compromise balanced sound for the venue.

    If you want to build yourself a pro audio system I would first look at high sensitivity speakers like perhaps line arrays or horns.

    OR perhaps you like the sound quality attributes with pro audio equipment which I would describe as a somewhat grainy/metallic sound. Pro sound usually does have a decent frequency response because it's usually setup with EQs so maybe you prefer that. Highs can have a "sizzle" to them which I know that there are people who prefer that.

    Another Idea is to go to a place that sells real studio speakers and audition some studio monitors. They have their own unique "revealing" sound that you may find appealing. I'd describe them as "mini" pro audio speakers... Perfect for pro-audio sound in a small room.
     
  14. Greg Monfort

    Greg Monfort Supporting Actor

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    >Sound reinforment speakers are tuned higher- theres no getting around that- however the argument that tuning a speaker higher gives better "punch" seems to break down, i believe- because as as the tuning frequency gets lower, and lower- the response approaches that of a sealed speaker of the same volume, and we all know 2nd order (sealed) loading has better delay response and has a characteristic tight punch.

    ====

    Actually, for prosound apps, you have it backwards, IOW they design some distortion in to increase the 'punch/slam' factor, which refers to its dynamic range capability over 'x' BW. The average concert uses slightly underdamped (ringing) alignments tuned to between 40-55Hz to maximize the 60-80Hz BW and 'lift up' the efficiency to maintain it through 300Hz to cover kick drums, etc. and blend to a HE mid horn, so depending on room size you'll need from one-four HE 15" suitable for XOing to a 300-500Hz horn/mains chnl (or equal) if you want to go 'live'. [​IMG] BTW, 40hz is typically > -24dB WRT 60Hz after EQing the LF stack to maximize 'punch/slam' and minimize overdrive.

    That said, speakers at a concert are making music, whereas in the home the speaker is a signal reproducer, so should be as accurate as practical and where low GD, etc., comes into play.

    Anyway, for this to be semi-relevant for HT, we're back to needing to accurately meet the DD reference peak levels (105dB/mains, surrounds, 115dB/LFE at the listening position) in the 20-20kHz BW to get the proper 'punch' for movies.

    ====

    >So overall, they are still able to achieve 115dB+ peaks in my 3000 cu ft. listening room. This is as loud as any concert, and louder than I ever care to listen, except for brief blow-your-socks-off demos.

    ====

    Nice Dynadios! It broke my heart when they left the DIYer high n' dry. I don't do concerts anymore, but when I was involved with them they were averaging 115dB at the FOH console and limited to a 10-15dB dynamic headroom, though the speaker stacks were calculated based on 30dB to hopefully keep from blowing any up during a performance. Regardless, sustained >100dB average in our acute hearing BW is a recipe for early hearing loss so I recommend keeping the average to
     
  15. Dave Milne

    Dave Milne Supporting Actor

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    Brett,
    I cut them out myself from two layers of 1/8" foam.

    Greg,
    Yeah, it's a bummer that Dynaudio exited the retail raw driver business. I don't have the disposable income to spring for the $30K - $80K "Evidence" line. Of course, the Confidence C4s are not bad at "only" $16K...[​IMG]

    Matthew,
    I don't know how much equipment auditioning you have done, but if you haven't heard a well-set-up, high-end system, you should pay a visit to your local hi-fi boutique. You may find out that you prefer quality over quantity.
     
  16. Paul Spencer

    Paul Spencer Stunt Coordinator

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    Matthew Will,

    One thing to remember about PA speakers is that they have tradeoffs that aren't acceptable to most in a home environment. PA speakers are very large, very efficient and have less bass extension. A 6.5" hifi midbass driver is designed to handle from 40Hz - 3 khz. A 12" PA driver will do perhaps 80 Hz - 2 kHz with 4 x the power handling while it requires 10% of the power to achieve the same SPL, so the max output is about 16db greater. But it needs a larger box as well as a subwoofer to fill in the bass. A subwoofer based around a PA driver with high efficiency would be 18" and require a very big box. It's extension would go to 30 Hz and it would be louder than a Hifi sub, more likely to give you chest pounding bass, even louder than a sub with a driver like the Shiva which might move more air, but the Shiva has the advantage below 30 Hz.

    PA drivers are also designed for low power compression and low distortion. Good PA drivers are also very expensive. Good PA drivers like JBL and PHL can cost more than some high end drivers like Seas, Scan Speak and Focal, although it's difficult to compare as they are not really doing the same job.

    It all comes down to what you want to achieve. If you want to reproduce a rock concert at home, PA drivers are worth considering if you have the budget, the space and the time to get it sounding right. But also consider that hifi drivers can be easier to work with (flatter response), and you can get high SPL out of them by using multiple drivers.

    eg. construct a tower speaker using 4 x Peerless HDS 8" with 2 x Morel MDT 37 tweeter (a dome with quasi horn loading). Such a system would have a sensitivity of 96 db and a very high power handling, at least 400 watts rms. Add a pair of high output subwoofers (eg. Stryke AV15 or Adire Tempest) and you will have a system that will give you 110 - 120db, rock concert levels (if you have an amp that is up to the task). NOT suitable as a PA system, but appropriate to bring rock concert levels into your home.

    It can be done, but whether or not it SHOULD be done. If you want a system like this, factor in the cost of sound proofing your room as well! (did I mention hearing aids)

    PA systems based on hifi drivers:

    18" sub for home use

    A home theatre based around PA drivers ... follow the link to "loudspeakers"

    The bass pigs lair

    You might also find Cowan's speakers interesting - PA drivers used extensively for high output

    Also check out the LDSG, a great DIY resource ... the DIY bible!
     
  17. Paul Spencer

    Paul Spencer Stunt Coordinator

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    One more thing:
    I would avoid compression drivers for hifi. The good ones are very expensive, most of them that are affordable have nasty coloration. That's why I suggest using a few tweeters for high output instead.
     

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