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Thread: 4345 power requirements

  1. #31
    Senior Member markd51's Avatar
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    As for the wants of going bi-amp, I'm quite sure a pair of these beautiful "Hernia Makers" would be the cat's meow, and look quite lovely sitting between a pair of the majestic 4345's! The price of admission is a shocker though!

    Maybe one day they'll come with a smaller brother, and a more sane price. LOL

    https://www.youtube.com/watch?v=fTWjZz5Zgug

    https://www.youtube.com/watch?v=GOOASnJ5D9g

    For many decades, I always felt the McIntosh-JBL pairing was a match made in heaven!
    I don't think too many here will dispute my claims!

  2. #32
    Administrator Mr. Widget's Avatar
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    Since I think we have pretty well answered the original topic I’ll continue this OT discussion about multi-amping vs. going with a single amp channel per speaker.

    There are very good reasons to choose either route. I first biamped my system in the late ‘70s and have had many different bi, tri, and quad amped systems since. Along the way I have learned a lot. There can be very real benefits going the multi-amp route. On the other hand, tearing apart a well designed system and going multi-amp is a very easy way to spend a ton of money and sonically take a giant step backwards. You don’t need to know how many volts are required from the power supply to generate a specific power level with a given amp/speaker combination, but if you aren’t willing to do your homework, you should find a really good full range amp and use the passive network.

    Nelson Pass wrote in the introduction to his XVR-1 analog active crossover owner’s manual:

    Some audio products are designed for anybody who can put batteries in a flashlight. This product is not like that.

    Some audio products are designed so that you don’t have to study the manual. This product is not like that, either.

    Some audio products are designed so that you plug them in and you don’t have to fool around with them for a year before the system is greatly improved....

    His description is specifically about his rather complicated crossover, but it holds true for going active with any active crossover.

    The bottom line is that at the theoretical level a multi-amped system with very short cables between the amps and individual drivers is without a doubt the best way to go. That said, in the real world this is not always a possibility and a pair of well designed speakers with a high quality amp can also exceed your expectations.


    Widget

  3. #33
    Senior Member markd51's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    Since I think we have pretty well answered the original topic Iíll continue this OT discussion about multi-amping vs. going with a single amp channel per speaker.

    There are very good reasons to choose either route. I first biamped my system in the late Ď70s and have had many different bi, tri, and quad amped systems since. Along the way I have learned a lot. There can be very real benefits going the multi-amp route. On the other hand, tearing apart a well designed system and going multi-amp is a very easy way to spend a ton of money and sonically take a giant step backwards. You donít need to know how many volts are required from the power supply to generate a specific power level with a given amp/speaker combination, but if you arenít willing to do your homework, you should find a really good full range amp and use the passive network.

    Nelson Pass wrote in the introduction to his XVR-1 analog active crossover ownerís manual:

    Some audio products are designed for anybody who can put batteries in a flashlight. This product is not like that.

    Some audio products are designed so that you donít have to study the manual. This product is not like that, either.

    Some audio products are designed so that you plug them in and you donít have to fool around with them for a year before the system is greatly improved....

    His description is specifically about his rather complicated crossover, but it holds true for going active with any active crossover.

    The bottom line is that at the theoretical level a multi-amped system with very short cables between the amps and individual drivers is without a doubt the best way to go. That said, in the real world this is not always a possibility and a pair of well designed speakers with a high quality amp can also exceed your expectations.


    Widget

    What you say makes great logical sense, and I basically linked such a Milionaire's state of the art system for mostly giggles and amusement purposes only.

    A true reference system within more sane end costs could be put together-accomplished for a lot less money, take up a lot less real estate, and a lot less back strain also. This then leaves money to be used elsewhere in a system.

    Which as many would say, such is only as good as its weakest links-components.

    Let's say within the McIntosh Line-Up, and going single and simpler Stereo Amps, or Monos driving the 4345 Full Range. Such could be a McIntosh SS MC-452, with a respective 450 wpc on tap, various Monoblock Amps they have made, and if tubes are your preference, and you're not looking to wake the dead, a simple MC-275 could do the trick?
    Or their more massive and powerful MC-2301 Tube Monoblocks. Or older MC-501 Monoblocks.

    This list could be endless, and I'd probably be correct that running full range with a very good quality Amp and PreAmp just might net much greater sonic gains and pleasure as you touch upon rather than running the gamut with separate and an incompatible mix of various "dopey Musician's Friend" Amps, external crossovers, wiring, and all sorts of complications, which might defeat the end goals, and be a cluster you know what mess that in the end got you going backwards.

    I have zero doubt, that my "lowly" bought new pair of Bryston 7BSST2 Monoblocks, while not looking very imposing like some Amps, and like the ones I link to above, would very pleasingly drive a pair of perfect condition 4345's with aplomb, just like they do with my pair of 4430's.

    When I first got those Amps, they were a major disappointment, coming from McIntosh Amplification. I sure didn't know that those new Amps would need a good 200 hours of break-in time to strut their stuff. They were quite thin, lean and cold. Like I almost took the bass drivers out of the 4430's.

    No, I won't ever claim Bryston is the best Amp of all, but I will say they have worked out much better than very well, control those 2235H Bass Drivers with clean, tight uncolored definition, and non-muddied response, the mids and highs have excellent uncolored clarity-precision, and focus, these are not warm amps, but IMO very accurate and very quiet-clean amps. An with an unbeatable 20 year warrantee.

    No, there's no big blue eye candy meters like McIntosh, and akin to like what Ashley Roachclip once said on a Cheech and Chong Record-Acapulco Gold Commercial. "Hey Man, whatayou want, Good Grammer, or Good Taste"? LOL

    Same holds true with Audio gear, what do you want, good looks, or good sound?

    I've been slowly but surely working my system up piecemeal, state of art cabling here and there, and soon I think a dedicated line service and a nice Shunyata Power Conditioner for source components will be in my future.

    I'm now running a $900 Phono Cable to phono stage and a $900 Cable from Phono Stage to PreAmp, both pure OCC Silver, compliments of Audio Sensibility in CA.

  4. #34
    Senior Member Ian Mackenzie's Avatar
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    One of the reasons people can come un stuck with a passive to active crossover conversion is the assumption the passive network is textbook design. In a quality designed passive loudspeaker the crossover filters are custom calibrated to the specific drivers and placement on the baffle.

    The engineer then voices the crossover in a real room listening situation and makes further adjustments. Sometimes this will involve a panel of golden ear people to advise on system at various stages of the final iteration.

    So plugging in an active crossover with only text book crossover settings is going to be a step backwards.

    So how do you go about accurately setting up an active version of a loudspeaker?

    That will be the topic of a series of Webinars l will be hosting in a few months time.

  5. #35
    Administrator Robh3606's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    So how do you go about accurately setting up an active version of a loudspeaker?
    All you have to do is match the voltage drives to the individual drivers. So you measure the output of the passive crossover, create a target curve from that measurement and set-up an active curve to match it. As long as you can get a good measurement of the curve you should be good to go.

    Rob
    "I could be arguing in my spare time"

  6. #36
    Dang. Amateur speakerdave's Avatar
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    Quote Originally Posted by Robh3606 View Post
    All you have to do is match the voltage drives to the individual drivers. So you measure the output of the passive crossover, create a target curve from that measurement and set-up an active curve to match it. As long as you can get a good measurement of the curve you should be good to go.

    Rob
    The voltage drive of the passive crossover is calibrated into an eight ohm load. What load is used in setting the active crossover? Do you drive through an amp into an eight ohm load?
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

  7. #37
    Senior Member Ian Mackenzie's Avatar
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    Quote Originally Posted by Robh3606 View Post
    All you have to do is match the voltage drives to the individual drivers. So you measure the output of the passive crossover, create a target curve from that measurement and set-up an active curve to match it. As long as you can get a good measurement of the curve you should be good to go.

    Rob
    Hi Rob,

    Thatís the basics but doing it by Joe Citizen is a leap of faith. At least the was the view of Nelson Pass and Greg Timberís when we met to talk about an active crossover for specific loudspeakers,

    Greg was quite specific on how to go about it.

  8. #38
    Senior Member Ian Mackenzie's Avatar
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    Quote Originally Posted by speakerdave View Post
    The voltage drive of the passive crossover is calibrated into an eight ohm load. What load is used in setting the active crossover? Do you drive through an amp into an eight ohm load?
    Come along to the webinar

  9. #39
    Administrator Robh3606's Avatar
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    Quote Originally Posted by speakerdave View Post
    The voltage drive of the passive crossover is calibrated into an eight ohm load. What load is used in setting the active crossover? Do you drive through an amp into an eight ohm load?

    Take a look here. Curious to hear what Greg has to say about how to do it.

    Rob

    http://www.audioheritage.org/vbullet...del-1400-Array
    "I could be arguing in my spare time"

  10. #40
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    Quote Originally Posted by markd51 View Post
    Rock Concerts, I've been to quite a few. An ELP concert with the introduction of their Brain Salad Surgery release will make 20 pairs of those 4345 Speakers sound like a 9V Battery Pocket Transistor Radio. Ask me how I know!

    https://www.youtube.com/watch?v=wz6Mj8cROJw

    I was there for that concert as well as the one ELP did at the Long Beach Arena a couple weeks before. Did you spot me in the audience?

  11. #41
    Senior Member Ian Mackenzie's Avatar
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    On the subject of voltage drives there are several challenges

    1. Accurate data collection
    2. Curve fitting the active voltage drive
    3. Design of the active filter

    It might look straight forward but itís not once the effect of the passive crossover is fully investigated.
    A passive crossover interacts with the drivers as they are electro mechanical devices When the loudspeaker engineer/ designer finalises the passive loudspeaker design these interactions are accounted for.

    If you remove passive crossover you will find with professional test equipment that the passive crossover was contributing to the end result due to the behaviour of the filter elements and their impact on the drivers behaviour. Some of the effects are not so much voltage but effects on the dynamic behaviour of the drivers.

    This is where the skill of a engineer is required to interpret and make the correct decisions in the design of the active system.

    Typically the passive crossover has some problems and you donít want to make the mistake of copying those problems. But then you need to address what changes need to be made.

    We went through that exercise with the DD65000, DD67000, DD66000.

    The challenges are unique to each loudspeaker such as the 4345, 4343 and the 4344mk11.

    As mentioned this is a great topic for a webinar which l will look at a bit later in the year.

  12. #42
    Dang. Amateur speakerdave's Avatar
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    I think you mean one translates a curve from one system to another, guided by reference to new raw data, but not sure. There was a time, after a year or so of reading literary theory, I thought I would eventually be able to penetrate anyone's patois, if I wanted to bad enough, but no. I still hold out hope that I will eventually understand Don Lancaster and Douglas Self, but this is kind of like reading Helena Petrovna Blavatsky.

    As Giskard, Lancer, 4313B said more than once: "It's beyond the scope of these forums." Or maybe just me. But still, it's remarkable that you would take a shot at it.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

  13. #43
    Senior Member Ian Mackenzie's Avatar
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    Itís a case of what you donít know you donít know.

    There is a difference between an audio amateur (a dangerous one) and a world class engineer like Greg Timberís. I trust you respect that.

  14. #44
    Dang. Amateur speakerdave's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    It’s a case of what you don’t know you don’t know.

    There is a difference between an audio amateur (a dangerous one) and a world class engineer like Greg Timber’s. I trust you respect that.

    Oh yeah. That's certain. If I could buy his work, I would.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

  15. #45
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    Hi Ian,

    thanks a lot for your very detailed answers, really appreciate the time you put into it!

    Quote Originally Posted by Ian Mackenzie View Post
    The approach taken at the time was a 300 hertz crossover point was a 50/50 split in the amplifier power rating and a 800 hertz crossover point was a 75/25 in the power rating.
    This answers my question to 100%, thanks!
    Using 300hz as a crossover it is an even power-distribution on both sides. The difference in the required power is only caused by a difference in sensitivity.
    Your example of the 800hz crossover and 75/25 power split is what I had expected as well for the 300hz crossover. But 300hz seems to be to energy-intensive, great you brought this example up!

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