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JBL SDP-55 Audio/Video Processor Review

Francis Vaughan

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The highest quality music releases available anywhere are Blurays with Atmos/Auro3D recordings such as those produced by Morten Lindberg's 2L(whether or not you enjoy the genre, the recording and production is unmatched).
This really exemplifies the problem. These are really good, and are trying to deliver the experience. A pity few others are matching them. I can't get the vast majority of the music I enjoy in this format. The company reminds me a bit of Mercury, and their Living Presence recordings. A very eclectic set of perfomers and music, some fantastic stuff, and a lot of very niche stuff, and a pile of stocking stuffers. But a repertoire that is dwarfed by mainstream companies. It is great if you want a HiFi experience, but if your prime interest is music and not HiFi you are not so well served.
I basically dream of a time when I can listen to my favourite composers, favourite performers, in a manner that isn't some form of constrained HiFi format. Multi-channel sound has the potential, but other than niche players, we still, in 2020, have nothing.
I fear the problem is simply that there is no money in it.
 

audioBliss

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HTP-1 has serious difficulty as far as output level. It could barely get to 4 volts and above that would distort heavily. The SDP-55 is far superior on that front going up to 8 volts out.

Yes but who needs 8 volts? Basically the rare minority that would be running 16 channels Purify amplification. And in that case the performance of those amps would be ruined by the poor performance of the SDP-55 anyway.

Next best thing are the Hypex amps and I don’t know of any module needing above 3.5V. In fact most are around 2V.

The HTP-1 will give >100dB SINAD for Hypex amps and many advanced users have verified that Dirac and Dirac Bass Control works. Bass management works, actually everything seems to work on those processors.

I’ve read reports of Dolby Atmos with Dirac does not even work on the JBL/Arcam/Emotiva. Which is the number one use case of these units. It’s the first thing a customer of one of these would play. And that does not even work. Just to put things into perspective.
 

audioBliss

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@Francis Vaughan what are you even talking about? 2-channel music has vastly inferior recording and mastering compare to movies. The delivery format is also worse. If you try to listen to modern recordings on anything else that a Bluetooth speaker it’s horrible.
 

TimoJ

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HTP-1 has serious difficulty as far as output level. It could barely get to 4 volts and above that would distort heavily. The SDP-55 is far superior on that front going up to 8 volts out.
What practical everyday use has 4V output? As I mentioned, most home power amps use way below 2.7V voltage, many seem to use 1.5-2.0V. Is it like car's maximum speed, it's nice to know you can go 200mph?
 

Francis Vaughan

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@Francis Vaughan what are you even talking about? 2-channel music has vastly inferior recording and mastering compare to movies. The delivery format is also worse. If you try to listen to modern recordings on anything else that a Bluetooth speaker it’s horrible.
What sort of music? This is a how long is a piece of string issue. Modern pop music is crud. We all know that. I think a lot of recording studios would be quite miffed to be told that they are vastly inferior to movies. By what metric are they inferior? In what manner does movie production use vastly superiour recording processes? What particular technology is vastly superior?
 

audioBliss

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What sort of music? This is a how long is a piece of string issue. Modern pop music is crud. We all know that. I think a lot of recording studios would be quite miffed to be told that they are vastly inferior to movies. By what metric are they inferior? In what manner does movie production use vastly superiour recording processes? What particular technology is vastly superior?

I think it would be enough to mention dynamic range.
 
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amirm

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What practical everyday use has 4V output?
Just about every desktop DAC with balanced output produces 4 volts or higher. By following that standard, you are assured that you can drive just about every amplifier with balanced input to its max power. Bring that down and all of a sudden you have to play the match game of which amp can produce its max power with whatever the processor produces.

It is not like the AV industry has created its own voltage output standard and gotten the amp companies to follow. Each seems to have picked some random output voltage as their spec.

A $6000 processor will get compared to pro audio DACs which produce well above 4 volts. To struggle to get to 4 volts makes little sense.
 
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amirm

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With DACs, DSP and computer, a ground loop produced a low-level whistle of a few kilohertz in my system. It was cured by separating the mains earth from the DC output of a power supply. Protective earth remains intact, but no longer forms a loop. I use optical interconnects to the DACs, but the whistle still entered through the PSU ground. The high frequency of the whistle remains a mystery.
And this is the problem with this design. One has to design knowing that HDMI connection and bring with it, its own source of noise. My computer USB port is also very noisy but we don't see that impacting hardly any DAC I test. Here, I have had tons of other processors and AVRs on the same setup with no noise issue over HDMI. Yet all of these Arcam based products suffer from this problem. And the company on purpose avoids testing them this way by using a portable, floating HDMI source.

As an aside, their portable HDMI generator can't produce the J-test signal I use for testing. So they don't test for jitter over HDMI!

Let's remember that no one in the industry tests for how much noise your HDMI source has. The expectation is that the AVR/AVP doesn't care.

Here we have a very embarrassing situation where "bits are not bits!" Two digital paths from the same source produce different analog performance. This needs to be investigated and fixed.
 

anibal66

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I welcome the bipolar panther. It can better reflect the nuances in the conclusion of the review.
In other previous reviews, the product was flawed as a whole, but competitive for a particular appication.
For example, an AVR with a poor digital section, but good amp measurements when used through the analog inputs.
 

audioBliss

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Purifi amps without the buffer board. And the people who believed monoprice's spec that said they could produce such!

I even brought up that example. But it’s useless when the preamp performance is worse than the amps?

Don’t get me wrong all these should be able to deliver like 12V but they don’t.
 

Francis Vaughan

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I think it would be enough to mention dynamic range.
Sort of. Modern pop music is compressed, although we hear it isn’t as bad as it was. To some extent compression is an artistic tool, and back in the days of what I would call the glory days of rock and roll recording producers would be using devises like a LA-2 or a Fairchild 670 to liven up the sound. They still do. A local star oboe player was telling me that the final mastering of her latest chamber recording was going to go through one. But these steps are not the stupid steps that wreck the dynamic range of modern pop recordings.
The lack of dynamic range in many modern recordings clearly has nothing to do with the medium or the technology as there exist wonderful recordings. The problem is entirely down to production directed at a perceived target market. Many artists hate the final result but are told it is what is needed to succeed in the market. If your favourite artists are subject to such indignities it isn’t the fault of the technology.
Moreover there exist genres of music where idiotic dynamic compression is not applied and never has been.
 

digicidal

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Sort of. Modern pop music is compressed, although we hear it isn’t as bad as it was. To some extent compression is an artistic tool, and back in the days of what I would call the glory days of rock and roll recording producers would be using devises like a LA-2 or a Fairchild 670 to liven up the sound. They still do. A local star oboe player was telling me that the final mastering of her latest chamber recording was going to go through one. But these steps are not the stupid steps that wreck the dynamic range of modern pop recordings.
The lack of dynamic range in many modern recordings clearly has nothing to do with the medium or the technology as there exist wonderful recordings. The problem is entirely down to production directed at a perceived target market. Many artists hate the final result but are told it is what is needed to succeed in the market. If your favourite artists are subject to such indignities it isn’t the fault of the technology.
Moreover there exist genres of music where idiotic dynamic compression is not applied and never has been.

That's all tangential to the point. There are numerous reasons for better DR in theater applications. Few (if any) audio only recordings are mastered with the expectations that they will only be listened to at reference volume in a silent room - or at least as silent as possible. On the other hand, music is mastered to sound good when played in cars, on the radio, in restaurants, clubs, over phone lines, etc. As a result only a small portion of largely classical music is allowed to have much DR at all - due more to the target consumer's playback conditions than anything else.

So when mastering digital soundtracks, silence needs to be silent (or better yet having some ambience but still feeling "empty") and explosions, screams, etc. need to be ear-splitting. If you did that with an album... there will be more complaints than accolades most likely. So technically there should be more of everything in a SSP or AVR than you would have in an audio-only device... because it will likely be required at some point.

That ties in to @amirm's criticism of the HTP-1 and a lower output level than specified (which I actually missed in the review the first time). That's a non-issue in a desktop DAC IMO, which is likely to be used with headphones only or near-field monitors with wide gain adjustments. However in a theater context - it's a much more daunting to deal with component matching amps when you possibly need ~12 of them and they're already in the rack by the time you realize you needed a bit more output from the processor. ;)
 

Krobar

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Hi @amirm

Interesting review. The HDMI performance drop seems to explain the Arcam results vs yours for the AV40. Did you take any measurements from the RCAs? Just interested in how the RCAs perform as these units are effectively single ended and use a conversion chip for the XLR outputs.

Also are the reported issues with stereo vs multichannel in the AV40 review now confirmed asthe same misconfiguration as the Denon tested within a few weeks of it?
 

Koeitje

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It's mind boggling how badly designed these processors are. I can understand not hitting the same targets are stereo DACs, but there are always clear bugs in the firmware. Doesn't anyone give a shit? Is it really that hard? You'd think they would run these tests are sort out all the shit. Such as isolating the HDMI noise and filter roll-off. For $6000 this is a joke.
 

digicidal

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It's mind boggling how badly designed these processors are. I can understand not hitting the same targets are stereo DACs, but there are always clear bugs in the firmware. Doesn't anyone give a shit? Is it really that hard? You'd think they would run these tests are sort out all the shit. Such as isolating the HDMI noise and filter roll-off. For $6000 this is a joke.

I'm afraid even at these levels the attitude is that the device is a disposable product which will be obsolete by the time it's produced and will be replaced with the next version as soon as they figure out how to sell "voice of Satan" speakers and convince people to start drilling holes in their floors as well as their ceilings.

Unfortunately the days of nearly any technology being "built to last" or be "trouble free" are long over. Even the most disastrous AVR/PrePro is a bit more reliable than every other release of the iPhone. Heck, I've had my car for less than a year (and it cost almost 10X as much as the SDP-55) and it's already had 3 firmware updates, two recalls, and still has a few features that are "eventually going to get worked out"... and it's a collaboration between Toyota and BMW - so it's not like you can write it off to a lack of capital or experience. :rolleyes:
 
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