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Thread: Biamp crossover question

  1. #31
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    Quote Originally Posted by edgewound
    A real live orchestra does not use EQ...so why should precision monitors?


    Is it live or is it Memorex?

    I always get a kick out of those drips that think they can recreate an orchestra in their 20 x 14 x 9

  2. #32
    Senior Seņor boputnam's Avatar
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    Two examples

    Steve:

    Here's two examples of home EQ.

    First, is the 4345's. Measured at about 17.5-ft - not optimum for the cabinets, but it is the family room listening position. EQ is a Klark Teknik DN370. Channel 1 (upper) is L. The two knobs with glowing halos are -18dB notch filters (Q=32) at approx ~30Hz (upper knob on each) and ~165Hz (lower knob on each channel) - nodes of excitation in my room. I've been through four EQ's in this signal path over time - this EQ has the best sound, and requires the least correction (adjustment) in the fewest places (Hz), all else being unchanged. This has proportional Q - the Q increases (i.e., narrows) with increasing adjustment, focussing the affect of the adjustment.

    I posted a review a year ago (Review: KlarkTeknik DN370 graphic equalizer), or so. I use this same EQ in my FX roadrack - it wields incredible control to the engineer...

    Second, is the Alesis Monitor One's in my study. Measured at 4.5-ft. EQ is the Ashly GQX3102.

    Both these curves were established using laptop with SmaartLIVE 5.0 and Pink Noise, and the Transfer function (FFT). We have posted on this elsewhere, but in-short, Smaart takes a signal BEFORE the EQ (the reference signal) and compares it to a measured signal from a mic (Earthworks M30BX). In Smaart, the reference signal is time-delayed to synch with the measured signal. As a FFT, the two signals are subtracted, and the difference plotted as a line. Where there are peaks, the singal path / room has added dB / resonance; where there are troughs, the signal path / room has cut dB / absorbed.
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    bo

    "Indeed, not!!"

  3. #33
    Senior Seņor boputnam's Avatar
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    Quote Originally Posted by edgewound
    I disagree Bo...

    A real live orchestra does not use EQ...so why should precision monitors?
    Ah, but they do, man!!

    Why do you think they ALWAYS spend such dough during construction, and then are often having to refurbish and add acoustic panels in those halls? They try (and try, and try...) and physically tame the room.

    Take a look around any symphonic concert hall - those really interesting panels are not there for looks - they need to be there to improve the balance, reduce nodes, enhance dispersion, reduce resonance, etc.
    bo

    "Indeed, not!!"

  4. #34
    Senior Member edgewound's Avatar
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    I figured that would get a response.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  5. #35
    Senior Seņor boputnam's Avatar
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    Quote Originally Posted by edgewound
    I figured that would get a response.
    Dammit, edgewound!!

    I shoulda know you were just tossing a grenade... How'd I do...?
    bo

    "Indeed, not!!"

  6. #36
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by boputnam



    If you don't correct for the room excitations, you are not hearing a "neutral" sound (assuming I understand what you mean by that... ). All rooms behave differently - one must make adjustments since the speakers were not designed for their room.
    Fix the room!

    No, you missed the meaning of my comment... I was suggesting that most people who apply EQ to their systems probably screw up the sound more by "fixing" it.

    Widget

  7. #37
    Senior Seņor boputnam's Avatar
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    Yea, I know. Just tossing a grenade, you know!!

    But, you are exactly correct. To much fussing with EQ introduces hoards of undesireable (and unintended...!!) phase perturbations. Littlest is best.
    bo

    "Indeed, not!!"

  8. #38
    Steve Gonzales
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    E.Q.

    Thanks for all the great info. You guys crack me up with the way you bust each others balls

  9. #39
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Giskard

    I always get a kick out of those drips that think they can recreate an orchestra in their 20 x 14 x 9
    Damn! You mean I can't get the sound of a 75 piece orchestra in my apartment? Why did I buy all of this Stereophile recommended equipment?


    Widget

  10. #40
    Steve Gonzales
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    Quote Originally Posted by Mr. Widget
    Damn! You mean I can't get the sound of a 75 piece orchestra in my apartment?


    Widget
    Not according to B*se

  11. #41
    Senior Member edgewound's Avatar
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    Quote Originally Posted by Mr. Widget
    Damn! You mean I can't get the sound of a 75 piece orchestra in my apartment?
    Widget
    No...but it is possible to to get the sound of a guitar, piano, bass and drums....jazz club style. But y'already knew that.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  12. #42
    Senior Member Ian Mackenzie's Avatar
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    What was this thread about?

    Incidentally there is an outfit in the States marketing a switchable 3 way passive crossover for speaker builders. I understand they have been seen at the CES. That might give your more joy than screwing about with an active system if you are just trying out ideas for kicks. As I recall they are only $200-300 bucks and you can dial in 6/12/18 db slopes and a range of crossover points with quality parts. Sorry I don't recall the Brand.

    I think Steve would do well to visit Elliotts Sound pages. There are some excellent articles on crossover network fundermentals right up to advanced passive and active systems.

    About the 4345, its sounds better in the mids and upper mids not just because of the diamond surround diaphragm. The breakup modes of the 2122H are far less annoying than the 2121, the baffles are offset giving smoother response in the critical midrange and the 3145 crossover is miles better than the 3143.

    I've heard the 4343 and it sounds harsh and strident in its original form, particularly if it has not been carefully set up. Come to think of it I could also say the same thing about any uncoated diaphragm

    I don't think Eq is the answer to domestic listening room and loudspeaker design issues but if it makes you feel better use it. The devil is in the details and unless used by an expert they and a nightmare.

    Meaning no disrespect but Bo's room is far from the ideal and yes the Eq he had in there when I heard it did help the balance and the imaging.
    I understand he now uses less and better Eq. (Also never let visitors screw with your graphic..you'll be sorry!)

    The bottom line is your system is ony has good as your room. If the room sucks your rooted. Sell the flaming house or get divorced or go buy some top of the range AKG headphones and a Benchmark headphone amp.

    Of course how many really top notch HiFi's systems use or need a 1/3 active graphic? Sweet Bugger all. If your system sounds like a PA then its probably a good idea.

    Perhaps we are not talking Hifi here.

  13. #43
    Senior Member edgewound's Avatar
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    Wow...BTW...Sorry to go OT Ian.

    I didn't really toss a grenade Bo, I surely got your opinion, and that's cool.

    From a hifi listening standpoint I've discovered throughout the years that my greatest satisfaction has come from the minimalist approach, equipment-wise. The more inherently accurate and natural sounding the speakers are, the less tweaking needs to be done with EQ. Honestly...I like no EQ, no preamp...just disc player through a volume control straight into a good amp and then the speakers. For me, that really uncovers good or bad recordings with less stuff in between the disc and the music.

    I'm just talking 2 channel stereo, not home theater, but that might work well too...DVD direct from the analog outputs to amps...haven't tried that yet.

    I think most home listening rooms that aren't dedicated would do fine with wall to wall carpeting and some drapes or other soft coverings to quell wall reflections in addition to upholstered sofas, chairs, etc.

    Ok...that's my opinion...from the "less-is-more" school of thought...the speakers should required very little...if none at all...electronic "fixing".

    Have a Happy Easter
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  14. #44
    Steve Gonzales
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    Thank you

    Well, I've been running a tri-amped system for some time now, so I'm fairly familiar with the basics. I'm not doing this for kicks, I've got some 136a's that have been completely, professionally rebuilt, some 2123H's, 2397/2441's and about 4 pairs of 076's, so I'm serious about building a four way. I just wanted to get some advice about the crossover choices. I figured that I could go total active 4 way, tweeked bi-ampable 4way passive or custom 4 way passive. I admit that my questions are fuzzy but believe it or not, the answers would allow me to connect some dots about my final choice. I also might choose the 2235H for the bottom and I can get some 2122H's also, so I really need to figure this all out, looks like I'm leaning towards full active. Thank you, gentlemen, great info.

  15. #45
    Senior Seņor boputnam's Avatar
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    continuing off topic...

    Quote Originally Posted by edgewound
    ...I surely got your opinion...
    Wasn't so much opinion, as reality. I was classically trained on bass trombone, and my sister is an opera singer, so I've spent ample time in many halls, nationwide as many of us have.

    Acoustic architecture is critical to allowing for a "natural" sound to be heard by both the audience and the artists. Many stages are dead - so dead the orchestra cannot hear themselves. Others are too loud.

    Anyway, following are a few things to make the point.

    First, the acoustic engineer who has done great things for the Boston Symphony Orchestra, Dr. Beranek, and second, a quote relating to renovations at Davies Symphony Hall in San Francisco - renovations that cost nearly half the original capital cost. But this problem is almost universal to big halls.

    ----------------------------

    Louise M. Davies Symphony Hall, the concert hall component of the San Francisco War Memorial and Performing Arts Center, was built in 1980 at a cost of $28 million to give the San Francisco Symphony a permanent home. Previously, the Symphony had shared the neighboring War Memorial Opera House with the San Francisco Opera and San Francisco Ballet. Its construction allowed the symphony to expand to a full-time year-round schedule.

    Designed by Skidmore, Owings & Merrill and Pietro Belluschi along with acoustical consultants Bolt, Beranek and Newman, its modern design is visually elegant both inside and out. A "cloud" of movable convex acrylic reflecting panels over the stage enables the acoustic space to be adjusted to suit the size of the orchestra and audience, while adjustable fabric banners around the auditorium can alter the reverberation time from approximately one to 2.5 seconds. Howevever, the hall's large volume and seating capacity and the relatively immature knowledge of acoustics at the time initially resulted in less than ideal results. Acoustical renovations under the direction of Kirkegaard Associates were completed in 1992 at a cost of $10 million, resulting in substantial improvement.

    The modifications included narrowing and shaping the walls above the stage to reduce the volume of space and increase useful reflections, replacing the cloud of reflector discs with a more effective array that covers a larger area and is computer adjustable, pulling in the walls of the floor-level seating to make the audience area narrower and more rectangular, adding aisles to replace the former continental seating, adding diffusing elements in various parts of the hall, and increasing the "rake" of the floor seating to provide better sightlines. In addition, risers were installed on stage to allow the musicians to both see and hear each other better. These and other improvements enhanced not only the acoustics but also the hall's beauty. The current seating capacity is 2,743.

    --------------------------------

    Support local music!
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    bo

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