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Thread: Strident sound with movies soundtrack

  1. #11
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by davef View Post
    Yes I am sure... Remember, Dolby Reference is 105dB peaks from EACH speaker. In that calculator, you must put in 1 speaker and since your room is treated, you must choose "Away" from walls. You will see you are nearly 3dB short, an additional 3dB of output requires double the amplifier power.

    I'd also recommend a class A/B amplifier...
    Dave,

    I have seen in this thread and, at least another, about what seem to be your misgivings about class-D amplification. What do you see as the most notable differences in behavior and/or clipping between class-D and class A/B that would lead to one being less desirable (accurate?) than the other for use with loudspeakers? I think your insights would be very educational.

    David

  2. #12
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by Ascend0577 View Post
    Dave,

    I have seen in this thread and, at least another, about what seem to be your misgivings about class-D amplification. What do you see as the most notable differences in behavior and/or clipping between class-D and class A/B that would lead to one being less desirable (accurate?) than the other for use with loudspeakers? I think your insights would be very educational.

    David
    I believe that if Morris Kessler from ATI stopped the 2000 series and replaced it with the class D then he was confident in the results of the hypex N-Core model or else the other line would have survived.

  3. #13
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by Ascend0577 View Post
    Dave,

    I have seen in this thread and, at least another, about what seem to be your misgivings about class-D amplification. What do you see as the most notable differences in behavior and/or clipping between class-D and class A/B that would lead to one being less desirable (accurate?) than the other for use with loudspeakers? I think your insights would be very educational.

    David
    Class D amplifiers produce switching noise, it is just how they work. Perfectly fine for most loudspeakers out there as most simply can not produce frequencies up that high. However, RAAL ribbons can and do produce these frequencies and even though we can't actually "hear" them, they can lead to fatigue.

    https://en.wikipedia.org/wiki/Class-D_amplifier
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  4. #14
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by joblain View Post
    I believe that if Morris Kessler from ATI stopped the 2000 series and replaced it with the class D then he was confident in the results of the hypex N-Core model or else the other line would have survived.
    Class D amplifiers offer rather significant manufacturing savings over class A/B by eliminating the challenge and expense of how to dissipate all of that heat. They absolutely have their place in the market and the technology is indeed getting better and better.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  5. #15
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by joblain View Post
    I believe that if Morris Kessler from ATI stopped the 2000 series and replaced it with the class D then he was confident in the results of the hypex N-Core model or else the other line would have survived.
    ATI still offers class A/AB amps. Comparing the cost/watt of the ATI 5 channel class A/AB and class D 200W/Channel offerings:

    AT4005 ATI Sig 200W x 5 class A/AB amp = $4795 Cost/Watt ~ .48 Cents/Watt
    AT525NC ATI N-Core 200W x 5 calls D amp = $2995 Cost/Watt ~ .30 Cents/Watt

    While the power output is the same the N-Core has features that the Sig amp does not have and the Sig amp has features that the N-Core does not have but it can't be denied that the AB amp cost more, runs hotter, weighs more, consumes more energy and rack space.

    Distortion in the higher frequency ranges introduced by class D amplifier design has been substantially remediated with N-Core design technologies but if the gap were 100% remediated why would anyone buy Class AB with all of the the deficits noted above? We know that the class AB market space is healthy and we see that ATI has some very fine AB offerings to complement their new class D product lines.

    ATI's 200W AT2000 AB has been replaced by 200W AT4000 AB & 200W AT52NC Class D
    ATI's 300W AT3000 AB has been replaced by 300W AT6000 AB & 500W AT54NC Class D

    ATI's class D offerings tell us N-Core improvements made it possible for them to embrace class D for use with primary hifi amplification. ATI's class AB offerings tell us that N-Core is not for everyone.

  6. #16
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by davef View Post
    Class D amplifiers produce switching noise, it is just how they work. Perfectly fine for most loudspeakers out there as most simply can not produce frequencies up that high. However, RAAL ribbons can and do produce these frequencies and even though we can't actually "hear" them, they can lead to fatigue.

    https://en.wikipedia.org/wiki/Class-D_amplifier
    The evidence that ultrasonics can be sensed ("heard") and can lead to fatigue is tenuous at best. There's that one Japanese study that used MRIs, but I don't think it has been reproduced by anyone else. I would say that ultrasonics "might" lead to some form of listening fatigue or stress, but the evidence that they really do is thin.

    I would think a bigger potential issue with class D amps is their higher output impedance, compared to class A/B amps, which can alter a speaker's frequency response. This is becoming less of an issue with modern class D amps.

  7. #17
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by dfurry View Post
    ATI still offers class A/AB amps. Comparing the cost/watt of the ATI 5 channel class A/AB and class D 200W/Channel offerings:

    AT4005 ATI Sig 200W x 5 class A/AB amp = $4795 Cost/Watt ~ .48 Cents/Watt
    AT525NC ATI N-Core 200W x 5 calls D amp = $2995 Cost/Watt ~ .30 Cents/Watt

    While the power output is the same the N-Core has features that the Sig amp does not have and the Sig amp has features that the N-Core does not have but it can't be denied that the AB amp cost more, runs hotter, weighs more, consumes more energy and rack space.

    Distortion in the higher frequency ranges introduced by class D amplifier design has been substantially remediated with N-Core design technologies but if the gap were 100% remediated why would anyone buy Class AB with all of the the deficits noted above? We know that the class AB market space is healthy and we see that ATI has some very fine AB offerings to complement their new class D product lines.

    ATI's 200W AT2000 AB has been replaced by 200W AT4000 AB & 200W AT52NC Class D
    ATI's 300W AT3000 AB has been replaced by 300W AT6000 AB & 500W AT54NC Class D

    ATI's class D offerings tell us N-Core improvements made it possible for them to embrace class D for use with primary hifi amplification. ATI's class AB offerings tell us that N-Core is not for everyone.
    Excellent post... Also do not forget the ATI 1800 series, with the 5 channel configuration available for $2395 which equates to ~ .37 per watt.

    As I have mentioned, I have nothing against Class D (I was promoting and selling B&O's ICEPower before it even hit the mainstream). Just not a fan of Class D in combination with RAAL ribbons, and that is based on feedback from the designer of these ribbons, many hundreds of customers, and personal experience.

    I'll share an interesting story... My father suffered from a horrible case of tinnitus. There was one room in the old house I grew up in that aggravated his condition to such a degree, that he couldn't even be in this room for more than 5 minutes. To the rest of my family, we couldn't sense anything and it became a mystery to me. I set out to determine what was the cause of this (his tinnitus acted up even if we had music playing in the room).

    For one of my visits, I brought with me some measurement gear capable of reading up to 40kHz. Sure enough, compared to other rooms in the old house, there was quite a bit of noise in the 30kHz region. Our dog Willie also avoided this room... I quickly realized my father wasn't imagining this, it was indeed measurable.

    Turned out the culprit was an old CRT TV that while plugged in behind a mess of wires, was never even used. I am not an audiologist, but the one my father was seeing agreed that this was very likely the cause and he had come across issues like these many times - even though on the surface, with hearing loss, it doesn't make much logical sense.

    We ended up throwing that old TV out and sure enough, my father had no more issues in this particular room compared to other rooms in the house...
    Last edited by davef; 09-18-2018 at 06:49 PM.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  8. #18
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by davef View Post
    Excellent post... Also do not forget the ATI 1800 series, with the 5 channel configuration available for $2395 which equates to ~ .37 per watt.

    As I have mentioned, I have nothing against Class D (I was promoting and selling B&O's ICEPower before it even hit the mainstream). Just not a fan of Class D in combination with RAAL ribbons, and that is based on feedback from the designer of these ribbons, many hundreds of customers, and personal experience.

    I'll share an interesting story... My father suffered from a horrible case of tinnitus. There was one room in the old house I grew up in that aggravated his condition to such a degree, that he couldn't even be in this room for more than 5 minutes. To the rest of my family, we couldn't sense anything and it became a mystery to me. I set out to determine what was the cause of this (his tinnitus acted up even if we had music playing in the room).

    For one of my visits, I brought with me some measurement gear capable of up reading to 40kHz. Sure enough, compared to other rooms in the old house, there was quite a bit of noise in the 30kHz region. Our dog Willie also avoided this room... I quickly realized my father wasn't imagining this, it was indeed measurable.

    Turned out the culprit was an old CRT TV that while plugged in behind a mess of wires, was never even used. I am not an audiologist, but the one my father was seeing agreed that this was very likely the cause and he had come across issues like these many times even though on the surface, with hearing loss, it doesn't make much logical sense.

    We ended up throwing that old TV out and sure enough, my father had no more issues in this particular room compared to other rooms in the house...
    Thank you, Dave and everyone else! That RAAL ribbons are a specific case due to their ability in the very high frequencies makes more sense to me than a blanket condemnation of class-D, with the generally very high switching frequencies involved.

    David

  9. #19
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by davef View Post
    Class D amplifiers offer rather significant manufacturing savings over class A/B by eliminating the challenge and expense of how to dissipate all of that heat. They absolutely have their place in the market and the technology is indeed getting better and better.
    Dave, now I know that ribbon and class d is not a good match, i feel sad that i invest almost 3.5k$ in amp that should not go together. Did you have a chance to listen the ribbon with the ati D model? If would like to have your opinion on this. Maybe the hypex ncore500 doesn't have the issue with your speakers, i think they sound pretty well in my room. Strident sound is felt only with very high references volume. I would like to watch movies with same impact than in theater without to drop down volume offently with friends because it's to loud and missing the bass and surround impact.

  10. #20
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    Default Re: Strident sound with movies soundtrack

    Quote Originally Posted by joblain View Post
    Dave, now I know that ribbon and class d is not a good match, i feel sad that i invest almost 3.5k$ in amp that should not go together. Did you have a chance to listen the ribbon with the ati D model? If would like to have your opinion on this. Maybe the hypex ncore500 doesn't have the issue with your speakers, i think they sound pretty well in my room. Strident sound is felt only with very high references volume. I would like to watch movies with same impact than in theater without to drop down volume offently with friends because it's to loud and missing the bass and surround impact.
    Your situation is different, you are trying to achieve reference levels without having enough power to do so. This is why when you are at these volume levels, when you turn on Dolby Volume, it sounds better because Dolby Volume equalizes volume levels and limits the peaks.

    Are you using a subwoofer?
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

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