Sirius radio audio quality is getting to be amazingly bad. I like the Real Jazz channel. But cymbals and pianos sound all warbly and swishy. It sometimes is so amazingly bad that I am sure something is wrong with the whole system.

For me my favorite channel has become un-listenable and I am planning on canceling.

But before I do, I wanted to see if you know what their problem is. I mean maybe they need some technical help? Maybe we can recommend something to them?

I thought that it was related to the car being in motion, but I am not sure of that anymore.

Am I right in thinking that Sirius is some kind of satellite or digital radio system? If so, they're probably trying to cram too many stations into one multiplex and having to lower the bit rate of each station. It is also possible that the stations have to pay more if they want a higher bit rate and the station that you want to listen to doesn't want to stump up the cash.

James.

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JRP Music - Audio Mastering and Restoration.
http://www.jrpmusic.net

Yes, satellite radio.

But I am not sure this is a bandwidth issue.

It sounds to my ears like comb filtering on mono sources.

If we can show them how to fix this problem, that would be great.

Can the SoS rescue guys please give Sirius a call.

Or a mastering engineer. Please step up.

Quote DC-Choppah:

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It sounds to my ears like comb filtering on mono sources.

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Yes, that's exactly what low bit rate data compressed audio sounds like.

James.

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JRP Music - Audio Mastering and Restoration.
http://www.jrpmusic.net

Yes, it's the low bandwidth they use now. They've been steadily cramming more and more channels in at the expense of quality.

It's most noticeable (unlistenably so) in music with hi hats or jangly guitar, and less so in uber-limited pop and hip hop. The sad thing is that it doesn't have to be that way. When XM first came out they had a few "HD" channels that sounded great. Now it's total crap.

Also, they don't care, because 99.9% of their listeners won't ever notice it.

But it seems to be the worst on mono source recordings or mono recorded instruments.

When they play a mono recording from the 50's of jazz, the swerling, warbly sound is there in extreme measure.

Mono voice recordings like book radio also have very bad phasing issues (to my ear).

So what if it is as simple as the left and right audio channels are not in phase alignment through the signal chain?

Sort of the opposite of stereo problem in mono. This is problem with mono in stereo.

There may be a simple fix that FM radio folks worked out for mono material but that the satellite guys don't know about.

This is also of interest to me since some of the program material I work on is targeting for sat radio and I'd like to learn how to make it sound good there if possible.

I actually know an engineer who was a founder and VP at Sirius too and might be able to arrange some way to talk to them.

Sirius has a frequency allocation of 12.5Mhz, into which they fit 151 channels of audio. You do the maths.

Right, so that is 82 KHz available per channel.

See what I mean.

So if they used 44.1 KHz source material from a CD they should have enough bandwidth to not compress much.

If it was really a digital compression issue, then why does it sound the worst on mono sources. That doesn't make sense.

It sounds like a phase problem.

I am going to try to listen in mono only and see if that makes a difference.

Has anyone ever looked at the phase correlation between left and right coming from their broadcast?

Quote DC-Choppah:

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Right, so that is 82 KHz available per channel.

See what I mean.

So if they used 44.1 KHz source material from a CD they should have enough bandwidth to not compress much.

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You've misunderstood what's going on. 44.1 KHz is a typical sample rate for digital audio, but that's something entirely different to the available RF bandwidth.

CD-quality audio is sampled at 44.1KHz at 16 bit depth. That equates to 705,600 bits per second, excluding error correction. The spectral efficiency of a suitable digital radio protocol works out to about (0.7 bits/s)/Hz; You would need over 1MHz per channel to transmit uncompressed CD-quality audio. Sirius' 82Khz slots provide about 57,000bps. That equates to PCM audio at less than 5khz at 12 bits, which gives only marginally better audio bandwidth and dynamic range than a telephone line. Obviously, sending full-range audio over such a narrow link requires heavy compression. Sirius use HE-AAC, with a bit rate varying between 24kbit/s and 80kbit/s based on the programme material. HE-AAC is a remarkably efficient codec, but it's just unrealistic to expect artifact-free audio in such a relatively tiny amount of bandwidth.

Thanks for that explanation. I think I get it now.

And I tried today to listen to a particularly bad sounding tune (Real Jazz channel with Cedar Walton, mostly piano and drums) on the right channel only, but the sound was still very swerlly, and chopped up. After this experiment, my ears now tell me this is NOT a phasing issue between left and right. It sounds just as bad with one channel only.

I would equate the sound to a bit better than listening to 'on hold' muzak over a cell phone.

And I guess what you are telling me is that is about what it is.

Oh man. I give up.

So does anyone have any recommendations for producing music for this format? The electronic music channels sound pretty good.

I just talked to the guy I know from Sirius.

He confirms what you all have said. He says they have a finite bandwidth and that they have the proprietary control to dish out different amounts of bandwidth to each channel. That was their key thing they had over XM.

He said that they allocate the most bandwidth to the classical channels to make them sound good, but that leaves little for everything else. And now they have crammed in to many channels to try and get more customers.

Now that I think about it, the classical channels do sound pretty good.

@uphill, you really know your stuff on this, and I really appreciate your answer.

I have been looking into EQ settings for making my Sirius radio sound better when I came across this thread. It appears to me that since I incorporated a slight mid-range boost and removed the treble boost the Real Jazz channel, or in fact most of the channels now sound quite good in my car. What are the others hearing? Possibly they changed something in the transmission or may the different EQ settings now appear to make the Sirius radio sound a lot better.

Sure, narrowing the audio band to more mids does make the swirling cymbals less noticeable. But it still sounds bad. i have not noticed any improvement. Maybe it has gotten worse.

I found 'Call Me Maybe' on Sirius and a local FM channel at the same time. So I could go back and forth. Everyone in the car could hear that FM was clearly better. They described the FM version as having 'more music' and a 'much wider range of pitches and sounds'. And there were times when you could here the music chopping up.

I hope this is not too OT-

Cell data plans differ the world over, and the majority of places, I think, have much better cost benefit ratios than here (US); but it's hard for me to see any future for satellite radio with the increase in mobile devices coupled with affordable data plans.

The availability-and apparently market for-subscription service for Sirius at home via computer completely escapes me.

Services (apps) such as TuneIn provide streams from almost any "real" or internet radio on earth, often with a choice of stream quality, with results that usually vary from good to truly excellent. And of course, using a mobile device "adds" the full array of the computer user experience to "radio," such as video and just using the computer or mobile device for what it is. Try web browsing, video, or sending some mail with a Sirius radio.

With a mobile device, Sirius "kits" are not needed-indoor kit, antenna kit, portable kit, etc. I'm not seeing the upside to any satellite service intending to mimic the now vintage radio experience.

When in a WiFi zone, the whole cell data plan is moot, and there remains no reason at all for Sirius. Pay money for limited service. Of course, you'd have to have yet more kit to have it out of the car, unless your basic use was out of car, then you'd have to have a kit for in car use.

A single mobile device and be done with it all.

I do see a need and use for local radio at home or in car, but that's about it. But since those are bookmarked in TuneIn.....

I like the commercial free music in the car. I don't use it at home or anywhere else. I like the Jazz channels and many others and I keep up with new artists by listening. I like the knowledgeable DJs.

I might listen for an hour and a half per day. I am told that 1 hour of streaming internet radio is 52 MBytes of data. Please correct me if I'm wrong on that.

If I used a smart phone and internet radio for a month at 1.5 hours every work day, then I need about 20 days/month * 1.5 hours/day * 52 MBytes/hour = 1.5 GBytes / month

Those kind of plans run about $100/month.

I get satellite radio for about $12 per month. (Oh, But its sounds terrible!)

Quote DC-Choppah:

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If I used a smart phone and internet radio for a month at 1.5 hours every work day, then I need about 20 days/month * 1.5 hours/day * 52 MBytes/hour = 1.5 GBytes / month

Those kind of plans run about $100/month.

I get satellite radio for about $12 per month. (Oh, But its sounds terrible!)

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After losing everything in hurricane sandy, my wife bought a hotspot. It's totally non-contract, pay-as you go, she gets 5Gb/mo for $50 and I believe they have smaller plans. Works well, too. Since there is no advertising here, if you want to know more, drop me a p.m.

MadManDan

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Gear list: If you can't find it, grind it

Quote DC-Choppah:

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If I used a smart phone and internet radio for a month at 1.5 hours every work day, then I need about 20 days/month * 1.5 hours/day * 52 MBytes/hour = 1.5 GBytes / month

Those kind of plans run about $100/month.

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In the UK you can get that sort of data allowance for just £12 per month (or possibly even less if you know where to look). Fortunately, where I work I can use wifi which gives reasonable quality for background music on the stations that I've tried.

James.

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JRP Music - Audio Mastering and Restoration.
http://www.jrpmusic.net

Quote MadManDan:

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After losing everything in hurricane sandy, my wife bought a hotspot. It's totally non-contract, pay-as you go, she gets 5Gb/mo for $50 and I believe they have smaller plans. Works well, too. Since there is no advertising here, if you want to know more, drop me a p.m.

MadManDan

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It should be fine to mention a service provider here-I'm interested in your solution. You're a disinterested party.

Quote Jeraldo:

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Quote MadManDan:

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After losing everything in hurricane sandy, my wife bought a hotspot. It's totally non-contract, pay-as you go, she gets 5Gb/mo for $50 and I believe they have smaller plans. Works well, too. Since there is no advertising here, if you want to know more, drop me a p.m.

MadManDan

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It should be fine to mention a service provider here-I'm interested in your solution. You're a disinterested party.

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Yep, the forum rules on advertising are aimed at self/business promotion. Nothing to worry about if you are a 3rd party commenting on your own experiences for the benefit of other members. Hope that puts your mind at rest, no rules being broken

Andy

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When the going gets weird, the Weird turn Pro.