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In-dash HD Radio Catch-22 ?

P

PocketRadio

"IBOC 'HD' radio in USA Options"

rsta...@*********.netspam wrote:

"I'm also wondering whether the usual annoying analog compression (volume level constantly at maximum due to compressors and limiters) is present on the digital feed. From what I heard in my brief demo, the digital and analog had the same volume level, indicating they had the same d*mn compression."

On Thu, 08 Mar 2007 08:08:33 GMT, "Robert A. Staton" responded:

"This is a serious Catch-22. All but one station within 100 miles of my Western MA location appear to be processing analog and digital identically. If everyone had a stationary table radio processing could be separate, since blending to and from modes wouldn't happen often. In a moving vehicle in mountainous New England the digital is often lost. If the audio quality (levels, response, compression and other processing) changes every few minutes, the listener isn't going to tolerate it. Remember, the digital signal is a mere 1% of the analog signal."

http://tinyurl.com/2ugav9

"Great sound, is HDRadio worth it ?" December 9, 2006

"I have noticed a down side to HD Radio. When I have a good signal it sounds great, but if I lose the HD signal the volume will change and get quieter. This is annoying if you are in a fringe area. There's nothing like hearing the radio get louder and quieter as you drive."

http://tinyurl.com/2sgmff
 
There's no way to maximize dynamic range on the digital side, maximize loudness on the analog side, and have them match up perfectly! It ain't gonna' happen.

Most stations around here are quite a bit cleaner on HD than analog (less processing). WTQR (Greensboro) is in BLAST-OFF mode on both HD and analog. Others that were aggressively processing HD have backed off. WLYT (Charlotte...102.9) has great audio on HD1 AND HD2 now (HD2 was "wimpy" for a while).
 
Mike Walker said:
There's no way to maximize dynamic range on the digital side, maximize loudness on the analog side, and have them match up perfectly! It ain't gonna' happen.

Most stations around here are quite a bit cleaner on HD than analog (less processing). WTQR (Greensboro) is in BLAST-OFF mode on both HD and analog. Others that were aggressively processing HD have backed off. WLYT (Charlotte...102.9) has great audio on HD1 AND HD2 now (HD2 was "wimpy" for a while).
Click to expand...

And, consumers are going to say, "in-dash HD Radio ain't going to happen" ! Just, another dirty-little-secret ! :D
 
I talked with a guy at Best Buy over the weekend. He told me that the in-dash JVC HD unit is among their best sellers. Why shouldn't it be? At 199, it's not even more expensive than the other, less versatile units they sell!
 
Mike Walker said:
There's no way to maximize dynamic range on the digital side, maximize loudness on the analog side, and have them match up perfectly! It ain't gonna' happen.
Click to expand...

The one that scares me is AM HD. You are in HD mode. You drive under a power line. The HD keeps decoding as long as it can, but the power line obliterates the signal. Sooner or later, it switches to analog. Analog, though, is MUCH LOUDER power line interference, cut in abruptly. Until the lower lines are cleared, the digital signal decodable again. And if you go in and out of power line areas, in and out of really loud interference. VERY annoying - much more so that volume differences on FM or the loss and regaining of an HD-2 or 3 channel. That alone is enough of a safety issue to me - not to be startled while driving - that it puts me off of getting a car HD radio, because a lot of my listening would be to AM, there are two good music formats here.

At least in analog AM, I can hear the interference increasing in volume slowly, and turn down the radio before it gets too loud.
 
Mike Walker said:
I talked with a guy at Best Buy over the weekend. He told me that the in-dash JVC HD unit is among their best sellers. Why shouldn't it be? At 199, it's not even more expensive than the other, less versatile units they sell!
Click to expand...

Yea right - the in-dash HD Radio that I referred to is no longer available:

"Great sound, is HDRadio worth it ?" December 9, 2006

http://tinyurl.com/2sgmff

Just, another non-seller HD radio.
 
PocketRadio said:
"IBOC 'HD' radio in USA Options"

rsta...@*********.netspam wrote:

"I'm also wondering whether the usual annoying analog compression (volume level constantly at maximum due to compressors and limiters) is present on the digital feed. From what I heard in my brief demo, the digital and analog had the same volume level, indicating they had the same d*mn compression."

On Thu, 08 Mar 2007 08:08:33 GMT, "Robert A. Staton" responded:

"This is a serious Catch-22. All but one station within 100 miles of my Western MA location appear to be processing analog and digital identically. If everyone had a stationary table radio processing could be separate, since blending to and from modes wouldn't happen often. In a moving vehicle in mountainous New England the digital is often lost. If the audio quality (levels, response, compression and other processing) changes every few minutes, the listener isn't going to tolerate it. Remember, the digital signal is a mere 1% of the analog signal."

http://tinyurl.com/2ugav9

"Great sound, is HDRadio worth it ?" December 9, 2006

"I have noticed a down side to HD Radio. When I have a good signal it sounds great, but if I lose the HD signal the volume will change and get quieter. This is annoying if you are in a fringe area. There's nothing like hearing the radio get louder and quieter as you drive."

http://tinyurl.com/2sgmff
Click to expand...

"Duking It Out Over Datacasting"

"Let's digress for a moment to consider that not all non-fixed digital receivers are created equal. Mobile and portable platforms each present their own design constraints. In the mobile case, the biggest problem is Doppler shift from the potentially high speed of the moving antenna. Space-diversity antennas may be used here, whereas these are not practical in most portable systems. Portable (handheld or "pedestrian") receivers, on the other hand, may not suffer as much Doppler difficulty (unless they are being carried in a moving vehicle)..."

http://www.rwonline.com/reference-room/skippizzi-bigpict/05_rwf_pizzi_aug_1.shtml

"Digital Radio Mondiale (DRM)"

"When a receiver moves relative to the transmitter, then the various signal paths (multipath) to the receiver incur Doppler shifts (a shift in frequency). The overall signal the receiver 'sees' is a linear summation of all of these multipaths, and this gives rise to random Doppler shifts of the different subcarriers. These random Doppler shifts of the subcarriers destroys the orthogonality between the subcarriers and gives rise to what is known as 'inter-carrier interference' (ICI). Maximum Doppler shift, fD, max is given by... A parameter that is independent of frequency is the 'percentage Doppler shift to subcarrier spacing', and once the Doppler shift reaches a certain percentage of subcarrier spacing, reception will fail."

http://www.digitalradiotech.co.uk/drm.htm

"Digital Broadcasting in the World"

"An examination of multipath interference during low-speed and high-speed travel such as in Fig. 16 shows that whereas correction based on the pilot signal is possible with low-speed travel, with high-speed travel each carrier is shifted by ±Δfd (the Doppler shift frequency) and such correction is no longer possible.... It has also described in outline the problems that antenna gain, multipath interference and Doppler shift pose for reception of digital broadcasts by moving objects."

http://tinyurl.com/2yym62

More problems for in-dash HD Radio ?
 
There was a JVC HD radio IN THIS WEEK'S BEST BUY CIRCULAR, and that is the one I refer to. Don't have the model number in front of me, because I have nothing to prove. It's out there, it's selling. In fact LOTS OF THEM are selling according to the guy in car stereos at Best Buy in Hickory NC.
 
Mike Walker said:
There was a JVC HD radio IN THIS WEEK'S BEST BUY CIRCULAR, and that is the one I refer to. Don't have the model number in front of me, because I have nothing to prove. It's out there, it's selling. In fact LOTS OF THEM are selling according to the guy in car stereos at Best Buy in Hickory NC.
Click to expand...

I can see it now - "Reason for customer return": Doppler Shift and Catch-22 parallel analog/digital audio processing ! :D
 
Mike Walker said:
There was a JVC HD radio IN THIS WEEK'S BEST BUY CIRCULAR, and that is the one I refer to. Don't have the model number in front of me, because I have nothing to prove. It's out there, it's selling. In fact LOTS OF THEM are selling according to the guy in car stereos at Best Buy in Hickory NC.
Click to expand...

That is correct! I was just checking one out yesterday! And it sounds great! 8)
 
scanman1 said:
Mike Walker said:
There was a JVC HD radio IN THIS WEEK'S BEST BUY CIRCULAR, and that is the one I refer to. Don't have the model number in front of me, because I have nothing to prove. It's out there, it's selling. In fact LOTS OF THEM are selling according to the guy in car stereos at Best Buy in Hickory NC.
Click to expand...

That is correct! I was just checking one out yesterday! And it sounds great! 8)
Click to expand...

Just remember, to either leave your car in "park", or "neutral", and no beltway driving ! :D
 
And just be careful if there are people RIDING BIKES and they just chance to be sharing the same road!

Had an *incredibly close call* a coupla Summers ago because my jack*** ex-girlfriend decided to play with her boombox in the front seat and not watching where she was going or whom else might have been on the road at the time, plowing right into my $2000 Cannondale, placing a nice big dent in her car's hood and setting my right arm in a sling for three weeks afterward! (And I must mention: the only things digital within that boombox were the CD player and the frequency readout.........)

I didn't make any of the above up as the LORD is my witness.

;D So ya got to be careful with those things. If a digital-tuned analogue boombox plopped in the front seat can do this imagine the detrimental effect an IBAC rig might have on other bike riders....... ;D

And if you are a fellow bike rider sharing the road with an IBAC-listening car driver PLEASE at least wear a helmet!!
 
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