Pulling Good Analog Sound out of Severe HD "Self Noise"?

[Clark2]

I just found out my local classical station "uses the Extended Hybrid Mode for HD Radio, which allows us to allocate up to 120 kbps total for all our digital channels combined. We currently only broadcast two channels, our main (HD-1) at 64 kbps, and our secondary channel Viva la Voce (HD-2) at 48 kbps." This must be the worst case for cramping the bandwidth of the analog channel and is almost certainly killing my old tuner with "HD self noise."

I'm looking for guidance on two questions:

1) Is it even possible to get really good sound from the analog channel of such a station?

2) If so, what are the best tuners for the job? I'd guess the IF band-pass would have to have very steep edges -- a digital tuner might be indicated -- but doesn't this imply higher distortion? Other factors? -- Clark2

[W9TR]

1.) Yes
2.) Look for a tuner with a good post-detection filter. Narrow IF's with steep slopes will help but also add to distortion as you've noted.

Some of the best performing tuners are :

Sony XDR-F1HD
Sangean HDT-1

They use DSP stereo decoding and have very good HD self noise rejection.

Brian Beasley has a lot of good information on HD self noise on his website:

http://www.ham-radio.com/k6sti/


Did you run FMFool to see if you have a strong adjacent channel HD station?

If you have a strong HD adjacent, it will impact your tuner choices as you'll need a tuner with a lot of IF stages and sharp cutoff ceramic filters. Something like the MR 80 or Sansui TU-X1 will fill the bill. The Magnum Dynalab tuners, as good as they are, just won't work as well in that specific situation.

[Formerly YB-2]

While Brian Beasley has done about all that can be done with HD he cannot defy the laws of physics. There is no way to obtain high fidelity from HD radio broadcasts with the available bit-rates. Brian is pretty much a 'voice in the wilderness' in his opinions on the SQ of HD (though I admit to having stopped reading his treatise some years ago - :beatinghorse:).

[cleeds]

I just found out my local classical station "uses the Extended Hybrid Mode for HD Radio ... " This must be the worst case for cramping the bandwidth of the analog channel and is almost certainly killing my old tuner with "HD self noise."

I'm looking for guidance on two questions:

1) Is it even possible to get really good sound from the analog channel of such a station?

Yes, it is.

If so, what are the best tuners for the job? I'd guess the IF band-pass would have to have very steep edges -- a digital tuner might be indicated -- but doesn't this imply higher distortion? Other factors?

I'm not sure that a digital tuner offers any automatic advantage here. W9TR's suggestion of the McIntosh MR80 is a good one, and the MR80 is very much an analog tuner even though it has a digital readout. My MR80 still sounds great after all these years.

But having a strong adjacent channel with HD isn't imo the biggest problem, because the HD on your desired signal is likely to be just as big a problem.

Quality FM reception has always hinged a lot on location and the antennas, and that's still true. The better the receiving antenna, the higher the gain. The higher the gain, the less you'll notice the distortion inherent in a higher selectivity tuner.

[nicoff]

If you are open to other options, have you considered streaming non-local classical radio stations that are streaming at higher rate bps? KDFC for example, streams at 128k. Or subscribing to a music service and create your radio stations based on music that you like?

[Clark2]

...The higher the gain, the less you'll notice the distortion inherent in a higher selectivity tuner.

That's interesting! I never would have guessed it. Why would that be the case; not enough gain in the internal RF stages? -- Clark2

[Clark2]

...
2.) Look for a tuner with a good post-detection filter. Narrow IF's with steep slopes will help but also add to distortion as you've noted.
...
If you have a strong HD adjacent, it will impact your tuner choices as you'll need a tuner with a lot of IF stages and sharp cutoff ceramic filters...

About (2), can you then use a wide IF pass-band if the post-detection filtering is good enough, and get rid of the self-noise without increasing distortion?

I don't think there's any problem with adjacent HD. The nearest that I know of is 2.4 MHz away. Will check...

Thanks for the good information. -- Clark2

[Clark2]

...If you have a strong HD adjacent, it will impact your tuner choices as you'll need a tuner with a lot of IF stages and sharp cutoff ceramic filters.

Don't the HD sidebands actually overlap the bandwidth of an adjacent channel? Is it possible to overcome that even with a narrow IF? -- Clark2

[cleeds]

Don't the HD sidebands actually overlap the bandwidth of an adjacent channel? Is it possible to overcome that even with a narrow IF? -- Clark2

Yes, there is overlap into the first adjacent. The extent to which narrow IF filters will help that hinges on a lot of variables - that's the nature of FM reception. But consider that while the first adjacent channel is just 200 kHz away, the FCC typically spaces stations in any market by 400 kHz. To be fair, with today's crowded FM band (in the US), that doesn't always quite work in practice.

[W9TR]

Don't the HD sidebands actually overlap the bandwidth of an adjacent channel? Is it possible to overcome that even with a narrow IF? -- Clark2

Correct - the sidebands of first adjacent HD channels can become 'on channel' interference. Which is why it is so important to understand your local listening conditions. If you have any first adjacent channel issues then the problem is really hard to fix because of the on channel interference.

Narrow IF's help here, as does a directional antenna used to put the offending station in a null.

The easiest test to see if you have HD self noise is to switch your tuner to mono. If the noise goes away in mono, you have HD self noise or the signal you are receiving is not full quieting in stereo anyway. You need about 20 dB more signal strength to get full quieting in stereo vs mono. That's exclusive of HD self noise.

Tom

[Clark2]

...The easiest test to see if you have HD self noise is to switch your tuner to mono. If the noise goes away in mono, you have HD self noise or the signal you are receiving is not full quieting in stereo anyway. You need about 20 dB more signal strength to get full quieting in stereo vs mono. That's exclusive of HD self noise.

Tom -- Yes, I'm pretty sure I have HD self noise on one station, especially since another station of similar strength (at the tuner) without HD sounds quiet.

But you had seemed to imply (in your earlier post) that good post-detection filtering (or a better stereo decoder?) could compensate for a wide IF pass-band. That was the reason for my question about (2). Did I misunderstand, or can you get rid of the self-noise by post-detection filtering without increasing distortion by using a narrow IF?

The answer to this question would seem important for choosing a tuner to get great analog sound on a station with HD channels... -- Clark2

[W9TR]

Clark,
Narrow IF bandwidth and good post detection filtering both work to eliminate HD self noise.

Tuner implementations of wide and narrow IF’s and post detection filtering vary widely so it’s hard for me to make a generalization.

I think the only way to see if a tuner works for you is to try it out in your system. The proof is in the listening.

Tom

[cleeds]

... I think the only way to see if a tuner works for you is to try it out in your system. The proof is in the listening ...

+1. This is often true in audio, but especially so when evaluating a tuner. Reception conditions vary greatly and it's difficult to predict results with any accuracy.

[Formerly YB-2]

+2. Can do all reading of theory and analysis you want, but plugging in a proper tuner & antenna provides the correct answer.

[Clark2]

+2. Can do all reading of theory and analysis you want, but plugging in a proper tuner & antenna provides the correct answer.

I accept what you folks are telling me, but aren't you at all curious about how HD works and what specific artifacts it produces?

(Interestingly, the HD Radio group on Yahoo! appears to be dead -- the last post before mine is dated Feb. 20, 2014, and the moderator does not respond to email!)

I hear you telling me that HD does not sound as good as analog FM, but I don't hear any details about how it falls short. I know from my car-radio listening that it's much better than Sirius/XM. I presume that it's adequate in some situations (and it is certainly quiet). I suppose I'll have to find out for myself... -- Clark2

[Macuser]

^^^^I've had several very good tuners over the years and still have a couple of good vintage Mac tuners. My thoughts are no matter how good those tuners sound they cannot make up for the lack of programming, constant commercials or compression that is today's fm. Putting the same effort into a streaming set up will yield much better results and that's probably the reason Yahoo HD Radio group is no longer around

[cleeds]

I accept what you folks are telling me, but aren't you at all curious about how HD works and what specific artifacts it produces? -- Clark2

I've heard HD broadcasts more than a few times, and that's about all I need to know how well it works (not very) and what artifacts result (low fidelity).

(Interestingly, the HD Radio group on Yahoo! appears to be dead -- the last post before mine is dated Feb. 20, 2014, and the moderator does not respond to email!)

That doesn't surprise me - HD is essentially dead in the US.

I know from my car-radio listening that it's much better than Sirius/XM.

I'd say the net sound quality of HD and XM (via the satellites) is about the same. If you've found otherwise, it may be a result of the specific tuner you're listening to, and not the potential of the technology itself.

[rnrmf1971]

I've had 3 different HD tuners at my residence. The sound quality has widely varied between these 3 tuners but comparing to satellite radio, in my experience, isn't even close. The high frequency "swirling" sound that I've always heard in satellite radio isn't present on HD1 broadcasts, by and large. That sound on satellite radio literally makes me uncomfortable.

My issue with HD tuners has been how unforgiving they sound. The little Sony was very round sounding but had a higher noise floor than the HD tuner implemented in the Marantz AV8802A processor that I currently use and enjoy, and would think is as good as HD radio can sound.

There was a Sony on Audiogon, yesterday, btw.

[W9TR]

Clark, you asked about some of the specific artifacts HD radio produces and how it falls short.

From my listening with a Sony XDR-F1HD forced to analog only (no blend) vs HD1:

1. HD1 was unable to accurately reproduce massed strings on MPR 99.5 KSJN classical concerts.

2. On MPR A Prairie Home Companion I was unable to tell the difference between a new Martin guitar and a 50 y.o. Martin guitar both played by the company’s president. Both guitars sounded the same. On the analog main carrier the difference was clearly audible and I had a preference for the sound of the older guitar.

3. On HD1 I was unable to hear the hall sound on familiar classical recordings where it was clearly audible on the analog main carrier.

I sold the Sony XDR-F1HD and never looked back. HD radio is not a Hi-Fi medium.

HD radio is also the Camel’s nose under the tent in that Ibiquity has proposed an all-digital future with no analog main carrier - effectively obsoleting all of our analog tuners and removing the only hi-fi radio alternative we have.

Tom

[Clark2]

I've had 3 different HD tuners at my residence. The sound quality has widely varied between these 3 tuners but comparing to satellite radio, in my experience, isn't even close. The high frequency "swirling" sound that I've always heard in satellite radio isn't present on HD1 broadcasts, by and large. That sound on satellite radio literally makes me uncomfortable.

My issue with HD tuners has been how unforgiving they sound. The little Sony was very round sounding but had a higher noise floor than the HD tuner implemented in the Marantz AV8802A processor that I currently use and enjoy, and would think is as good as HD radio can sound..

Thanks, rnrmf1971 -- That's quite helpful. I have yet to hear good (that is, single-channel) HD in a quiet background on a good system. Sirius/XM, on the other hand, exhibits serious artifacts even in the car. I notice particularly on solo violins, and sometimes on solo piano, a high-frequency noise band that appears over the higher notes but that doesn't vary in frequency with the pitch of the notes -- some kind of peculiar processing artifact that, as you say, is quite unpleasant. I would not expect HD to sound that bad, based on the better codec they appear to be using, but the proof is in the listening... -- Clark2

[Clark2]

...HD is essentially dead in the US...

Not so in the markets where I normally listen. In the metro areas of both the Washington, DC, and Albuquerque, NM, more than half the stations I listen to (including university stations) have one or two HD channels. (Not statistically meaningful -- perhaps I'm just more aware of it now that my car has HD.) This is the reason I need to acquire a tuner that can work around it, if not receive it. -- Clark2

[Clark2]

...From my listening with a Sony XDR-F1HD forced to analog only (no blend) vs HD1:

1. HD1 was unable to accurately reproduce massed strings on MPR 99.5 KSJN classical concerts.

2. On MPR A Prairie Home Companion I was unable to tell the difference between a new Martin guitar and a 50 y.o. Martin guitar both played by the company’s president. Both guitars sounded the same. On the analog main carrier the difference was clearly audible and I had a preference for the sound of the older guitar.

3. On HD1 I was unable to hear the hall sound on familiar classical recordings where it was clearly audible on the analog main carrier...

Tom

Thank you, Tom, for your insights. Even though that Sony is not known for hi-fi analog-FM sound (something about actively adjusting the IF bandwidth to reduce noise on quiet passages, I think, though that probably wouldn't affect the HD sound), the comparison should be valid. -- Clark2

[rnrmf1971]

The comments about the Sony are accurate - it's very warm sounding and will not differentiate details and has a high noise floor by comparison to better tuners.
That said, for me, it was enjoyable for what it was - a cheap $129 Hd tuner. I wouldn't consider it audiophile by any measure, though. It's fun.

It's likely that the least expensive "audiophile" Hd tuner option, these days, is the Sangean digital out into your choice of DAC. Otherwise you're limited to the used market.

[Formerly YB-2]

Not so in the markets where I normally listen. -- Clark2
I wonder if this isn't the result of the station mgmt being sold a "bill of goods" (HD radio) with a contract covering a certain time-frame (10yr?) so they continue on until the contract is up. My local 'go-to' station used to go on & on about HD's 'CD quality' until enough of us serious listeners pointed out what a crock that was. Rarely hear about their HD theses days other than it is available for alternate programming.

[cleeds]

I wonder if this isn't the result of the station mgmt being sold a "bill of goods" (HD radio) ... My local 'go-to' station used to go on & on about HD's 'CD quality' until enough of us serious listeners pointed out what a crock that was. Rarely hear about their HD theses days other than it is available for alternate programming.

The history of HD radio in the US is one of repeated missteps that overshadow whatever potential the technology might have had.

Things started to go wrong from the moment iBiquity branded its in-band, on-channel digital scheme. The assumption, of course, is that "HD" stands for high-definition. But, as licensor iBiquity (and its successor, DTS) explain, HD radio stands for ... nothing at all. And it certainly never stood for High Definition, the company says. Someone should have told them that launching an entirely new product based on a deceptive trade name just isn't smart.

HD promoters touted the technology as CD quality on FM, and FM quality on AM. Neither claim was quite true, of course, even under ideal conditions. And given that one of radio's greatest benefits is its portability, that's quite a handicap, because when you're mobile, reception conditions are constantly changing.

The technology arrived just as the US broadcasting industry began entering a free fall, a consequence of consolidators such as Clear Channel overpaying for stations, and then struggling to cut costs in an effort to stave off bankruptcy. That meant there wasn't much money to invest in HD programming, further limiting HD appeal. At the same time, cost cutting on the FM and AM sides cheapened those products, too. Data shows that while people still listen - radio reaches about 93 percent of US adults every week, Nielson says - the time spent listening is down. Some of that is almost certainly because listeners have more choices today, and that only creates a vicious circle of declining quality.

And it gets worse.

The additional noise HD helped spew into the AM band limited the coverage area of many stations. And HD contributes noise on FM, too, which of course is the topic of this thread. Just as there were cuts in radio programming budgets, there have been cuts in engineering budgets. So maintaining tricky things such as keeping the timing of the analog and digital signals synchronized (which is no small feat, and which is needed because a radio will switch back and forth as the HD signal fades) are likely to go unattended. Any HD signal problem - including things as simple as a computer lock-up that interrupts the programming - can go on and on and on for days. The engineer and programmers are too busy to listen. Or maybe they don't care. I've seen this happen even at major stations.

Many stations have turned off their HD encoders. Of course, many still use HD because it has marketing appeal to have "HD" attached to the end of a station's call letters.

But remember, even when it works: HD isn't high definition.

[nicoff]

The history of HD radio in the US is one of repeated missteps that overshadow whatever potential the technology might have had.



Things started to go wrong from the moment iBiquity branded its in-band, on-channel digital scheme. The assumption, of course, is that "HD" stands for high-definition. But, as licensor iBiquity (and its successor, DTS) explain, HD radio stands for ... nothing at all. And it certainly never stood for High Definition, the company says. Someone should have told them that launching an entirely new product based on a deceptive trade name just isn't smart.



HD promoters touted the technology as CD quality on FM, and FM quality on AM. Neither claim was quite true, of course, even under ideal conditions. And given that one of radio's greatest benefits is its portability, that's quite a handicap, because when you're mobile, reception conditions are constantly changing.



The technology arrived just as the US broadcasting industry began entering a free fall, a consequence of consolidators such as Clear Channel overpaying for stations, and then struggling to cut costs in an effort to stave off bankruptcy. That meant there wasn't much money to invest in HD programming, further limiting HD appeal. At the same time, cost cutting on the FM and AM sides cheapened those products, too. Data shows that while people still listen - radio reaches about 93 percent of US adults every week, Nielson says - the time spent listening is down. Some of that is almost certainly because listeners have more choices today, and that only creates a vicious circle of declining quality.



And it gets worse.



The additional noise HD helped spew into the AM band limited the coverage area of many stations. And HD contributes noise on FM, too, which of course is the topic of this thread. Just as there were cuts in radio programming budgets, there have been cuts in engineering budgets. So maintaining tricky things such as keeping the timing of the analog and digital signals synchronized (which is no small feat, and which is needed because a radio will switch back and forth as the HD signal fades) are likely to go unattended. Any HD signal problem - including things as simple as a computer lock-up that interrupts the programming - can go on and on and on for days. The engineer and programmers are too busy to listen. Or maybe they don't care. I've seen this happen even at major stations.



Many stations have turned off their HD encoders. Of course, many still use HD because it has marketing appeal to have "HD" attached to the end of a station's call letters.



But remember, even when it works: HD isn't high definition.


Very good post. Your last sentence:
“But remember, even when it works: HD isn't high definition” makes it clear that you can’t polish a turd.

[Clark2]

...The assumption, of course, is that "HD" stands for high-definition. But, as licensor iBiquity (and its successor, DTS) explain, HD radio stands for ... nothing at all...

I though it stood for "Hybrid Digital," which at least makes sense. -- Clark2

[Formerly YB-2]

From iBiquity's standpoint it is "H"and us the "D"ollars. Have yet to read anything good about the company.

[Clark2]

Update: Setting aside HD for the moment and leaning toward modern digital tuners for my closely spaced, HD-blighted, public-radio band, I approached DaySequerra again. Through their local dealer they are willing to send me a demo M4.2Si (which incidentally has HD and AM) to try out in my situation. (I can't afford the M4FM, which is now only available with HD and is more than 4X the price. For comparison, the MD90T new is approaching twice the price.)

I will fire it up when it gets here and report on reception, sound quality (heavily dependent on local programming of course), and usability. Unfortunately I have no direct comparisons here (except the ancient Yamaha CT-800, which can't cope with the HD noise), so you'll just have to trust my aging ear and dulled sensibilities. Should be an interesting experiment for only the cost of round-trip shipping... -- Clark2

[cleeds]

... they are willing to send me a demo M4.2Si ... I will fire it up when it gets here and report on reception, sound quality ... and usability ...

I'll be interested in your results! Will you also please share some of the other details, such as the antenna you're using, how it's mounted, and your distance from the station transmitters?

[Formerly YB-2]

Sounds like a plan (a good one). If you want to try a refurbished Yamaha T-85 at the same time, I'll make the same deal.

[cleeds]

... If you want to try a refurbished Yamaha T-85 at the same time, I'll make the same deal.

What an offer! Ya' gotta love AA!

[Clark2]

I'll be interested in your results! Will you also please share some of the other details, such as the antenna you're using, how it's mounted, and your distance from the station transmitters?

cleeds -- These details were previously posted at https://www.audioaficionado.org/showthread.php?t=45191&page=3 (Post #26). A bit more information from fmfool: The "ft AGL LOS" is 217.0. I suppose that is telling me I would need a mast 217 ft high to get LOS!?

I have been playing with the MD205. It does help some with the ancient Yamaha tuner. I can tune it to WBJC and then increase the gain to get more quieting. There's a sweet spot; if I increase the gain too much, the noise level increases again, not surprisingly.

More observations on this station with this tuner, in case you can interpret them:
1) The signal level (as reported by the un-calibrated meter on the Yamaha) increases significantly at night (and the sound gets quieter).
2) I can occasionally hear fading (flutter?), perhaps as airplanes produce multi-path at my site. (The Washington, DC, metro area has four major airports -- five if you count Baltimore -- and everywhere is under a landing pattern some of the time.)
3) The background noise is sometimes just varying hiss, but sometimes it sounds like low "static." From the cryptic descriptions of multi-path distortion that I've found, I gather that static is one of its manifestations. Since I'm in a residential area with no metal structures and no large buildings in sight, however, it seems unlikely that any multi-path is coming from a local source.
4) The station engineer tells me that they do have a single HD channel -- I'm looking forward to comparing that to their analog -- but that it's currently turned off. So I think the noise I'm hearing is not HD self-noise, though it might be coming from a stronger alternate-channel HD signal... -- Clark2

[Clark2]

Sounds like a plan (a good one). If you want to try a refurbished Yamaha T-85 at the same time, I'll make the same deal.

That's certainly a tempting offer -- sounds like a wonderful tuner! -- but before I take you up on it, I should play with the demo a while and see if there's any point in such a comparison in my situation. -- Clark2

[Clark2]

I'll be interested in your results!...

OK, you asked for it. Here follows a semi formal comparison between the Yamaha T-85 and the DaySequerra M4.2Si. -- Clark2


Motivated by "Weirdcuba"'s "Can I have it all?" [Tuners thread 29983], I searched for a tuner in current production that might provide both great analog FM sound and FM-HD (when available) and came up with the DaySequerra M4.2Si. This sleek little rack-mount is a fully digital tuner that costs about $1100 and offers both DSP decoding of the analog channel and proprietary decoding any HD channels available on either AM or FM broadcasts. It has an Ethernet connector (and expects to be on a LAN, although this is not absolutely neccessary) and both analog and digital outputs. It's most conveniently controlled through its Web page with a smart phone or other computer connected to the same LAN, although manual control is possible from a three-button panel interface. Since no audiophile reviews were available -- it's mainly intended as a station monitor for broadcast engineers -- DaySequerra was kind enough to lend me a demo unit to audition, and I ran Ethernet and RG6 cables through the walls to feed it from my LAN and an in-attic 4-element yagi.

I really wanted to like this tuner. My main goal is good analog reception in the presence of HD sidebands (no problem for an HD tuner, right?), but I also wanted to try out FM-HD itself, since both classical stations in my area have HD, one using the full ~120 kbps for a single channel -- maybe worth listening to. To make my audition more meaningful, "Formerly YB-2" kindly offered to loan me his refurbished Yamaha T-85 for a direct comparison.

Conditions for Comparison:

I fed the RG6 from the antenna through a Magnum Dynalab MD 205 antenna tuner/amplifier/attenuator (both to make up for the splitter insertion loss and to give the M4.2Si enough signal to switch to stereo on both stations) to a splitter and thence to the two tuners. Their analog outputs (plus the coax digital output from the M4.2Si) were fed to separate inputs of my Yamaha A-S501 integrated amplifier and on to either a Stax SR-5 electrostatic "earspeaker," driven from the speaker outputs of the amp via a Stax SRD.6 adapter, or a pair of Beogram M 70 main speakers. I have no convenient way of equalizing the levels between the two tuners, which therefore required minor volume adjustments on switching between them. (In practice the differences were obvious enough that I don't believe this caused a major confusion, as you will see below.)

Caveat: I'm nearly 72 years old, and the highs in one ear are nearly gone above about 4000 Hz. (The other ear is at least as good as most people's my age.) I can also no longer be considered the discriminating listener that I once was. (I've been ignoring hi-fi for quite a few years.) It's primarily the failure and ongoing replacement of several ancient components that's brought back my interest recently.

Listening Impressions (Short and Not So Sweet):

The T-85 provides MUCH more high-frequency range than the DS M4.2Si (forced to analog). It also produces a more open lower mid-range/upper base. The overall effect is a cleaner, more realistic sound, noted on both stations.

Based on the above observations I wondered if DS had skimped on their D:A and audio outputs, so I compared the audio out with the digital out through the A-S501. If there are any differences, they are not obvious, so the lack of highs and muddly lower mid-range seem to originate in the DSP, not the audio section. It's not a matter of choosing the wrong de-emphasis setting either. The M4.2Si comes with a 75 microsecond default (which I verified). Changing that to 50 microseconds increases the highs somewhat, but not nearly enough to equal to the T-85. (Conversely, a possible European setting on the T-85 could not fully explain its much "hotter" high end -- see below.)

On my main speakers the T-85 sound seems rather "hot" at the high end, but this can be adjusted down successfully with the amp's treble control. (Have others had the same reaction to this tuner?) For some reason I did not have this reaction to the T-85 on the "earspeaker" -- I hope the Stax isn't the next component to fail! The M4.2Si still seems rather dull in the highs and generally lacking in "presence" on the mains. Unfortunately I have no "absolute" standard with which to compare each tuner.

Functional Impressions:

The T-85 seems to require the "very narrow" IF bandwidth setting and the "direct" RF mode setting on both stations -- probably a result of those HD side-bands and/or weak signal strength and/or multi-path -- but there's no audible trace of HD self-noise -- perhaps a result of the true analog multiplier in the stereo decoder? Not surprisingly the M4.2Si has no self-noise, but as mentioned above, it isn't sensitive enough on its own to get full stereo on the weaker station without gain from the MD 205. As set up, both tuners suffer about the same degree of noise on the weaker station, which I assume from the sound is due to multi-path -- it's 1Edge, not LOS -- rather than insufficient signal.

One other comment may be significant to many (like me with my apparent multi-path problem): The M4.2Si offers no convenient means of displaying signal strength for antenna adjustments, etc. (Yes, it gives a "CdNO" -- carrier over noise -- value in dB, but this is only valid on HD stations since it's apparently the HD carrier that they are referring to. Numerous other data are available on a separate Web page but not explained. (In fact there's been a major software (?) upgrade and the manual hasn't caught up yet.) Most or all of these data may come from some internal iBiquity chip and in any case do not seem useful for analog broadcasts.

Yes, I really wanted to like the M4.2Si, but in the end the T-85 proved much better both sonically and functionally. -- Clark2

[W9TR]

The T-85 is an excellent tuner. It has a good post detection filter and a dynamic variable blend circuit that will help reduce hd self noise on weak stations. If you found this tuner to be to your liking then a number of vintage high end tuners should work well for you.
Tom

[cleeds]

... I really wanted to like the M4.2Si, but in the end the T-85 proved much better both sonically and functionally. -- Clark2

Thanks for posting this review! I am disappointed with your results using the DaySequerra, but not really surprised. Making a first class FM tuner has always been a pricey undertaking. I know that some tuners rely on DSP for processing, which should reduce complexity and cost, but there doesn't yet seem to be any shortcut to getting top performance from FM.