Transmission1

After plugging my DAB radio through the hi-fi and being less than impressed with the sound quality I put my old Kenwood FM/AM radio set through it today.
What a massive improvement in sound quality. Instead of the compressed stunted flat sound that I got with DAB it is singing through now.
A classic case that digital is not always better.

I was just talking about that with a workmate today, sold us a dummy with DAB thats for sure.

He measured the audio with some software, some channels had no audio content above 3KHz, think FM goes much higher.

Come 2015, we are truly screwed, driving in the country and listening to radio, I think not.

The US Sirius XM idea is better although requires subscription over there. Lots of choice though and much better quality than DAB here.

pw

During the initial test phase of DAB, only a few stations were active and used bitrates of 320kbps.
So the sound quality was very good, still not as good as a proper FM signal, but good.

However, when it became active and a greater number of stations came on air, the multiplexing/bandwidth issues forced them to all reduce bitrates, some as low as 32kbps.
In other words, utter garbage.

It was a total con from beginning to end.

BBC Radio 1 broadcasts on DAB at 128Kbps. I think there are a couple of stations (can't remember which ones) which broadcast at 160Kbps.

I have DAB in my car and when switching from BBC R1 on DAB to BBC R1 on FM the quality is greatly increased. Once the digital radio switchover is completed I guess they will bump up the bit rate of the DAB stations. 128Kbps is poor, even 256Kbps is a marked improvement and the least sensitive of ears could tell the difference. 320Kbps would be nice but it's a bit overkill, after all MP3 download services are only jumping on the 320Kbps bandwagon just now.

Gave DAB a go a while back i thought it sounded fine, but don't use it now, not a hi fi fan just an old NAD tuner in the back room couple of converter leads and a set of Harman karadan PC speakers run of an dare i say it, micro ATX radio station studio built in my daughters school, Academy FM 107.80 MHz good sounds plays all the 80's 90's bit of the 70's as well, not all this crap today, proper music with lyrics.

DAB uses the MP2 codec if memory serves, and like MP3 is a lossy codec.
So even with bitrates as high as 320kpbs, there is still a large chunk of time domain (or psycho-acoustic) information missing.
Also, the theoretical dynamic range of uncompressed 16bit audio (around 96dB) is also curtailed by lossy codecs.

DAB is a fudge, in the same way the other lossy systems like MP3, AAC and WMA are.
None of them approach the quality of uncompressed 16bit CD audio, and in a lot of cases not even a good strong FM signal.

Theoretically, MP2 at higher bitrates should equal the performance of MP3, but I digress.

Kind of ironic the first post on here for ages has nothing to do with radio Dx . Have any of you ever Dxed dab from the continent?

Given that I don't own a DAB radio (don't intend to, and I don't know anyone who has one or intends to)
it would be a bit tricky to DX there

Does the continent use the same band, if so wouldn't DX be impossible because there aren't any gaps like you get with FM, the entire channel bandwidth is used with each transmitter?

acl777 wrote:Kind of ironic the first post on here for ages has nothing to do with radio Dx . Have any of you ever Dxed dab from the continent?

Yes, sat up on Beachy Head in Sussex one afternoon a few years ago I received VRT-DAB from Belgium and a German MUX on 8C using my in car JVC. Reports on boards such as Digital Spy of signals making it across the North Sea are common during periods of enhanced propagation.

Results on DAB seem to vary considerably depending on the receiver and that I assume is down to the quality of the D-A conversion. My JVC 1500 that I've had for ten years in the car sounds fine, even on high frequency vocals and material with lots of harmonics. The old portable in the house, a Goodmans, sounds terrible listening to the same signal. I know DAB has its limitations, it's one of the problems of being the innovator of new technology but I'm happy to come to its defence.

Mobile reception around here and on my travels to the SW is excellent with a roof mounted 1/4WL. The extra choice of stations is welcome too from speech to dance music and if you're unfortunate enough to live equidistant from three 693kHz transmitters you'll know just how poor AM signals can be even during the day so I'm now able to listen to 5Live in the car.

I've Dxed digital tv from Belguim . As far as dab goes I have heard that its possible to receive Danish muxes during tropos from as far down as the Suffolk coast. I think dxing is harder partly because of lower powers and as has been previously said frequency allocation. I personally hate digital and would rather completely return to analogue . Whatever happens I think a dab Dso from FM is years away if it ever happens.

I've done a antenna mod on a portable DAB set, to allow for an external antenna to be connected, but the way I've done it is so the built in twig can still be used at the flip of a switch.

Twistedtransistor wrote:I've done a antenna mod on a portable DAB set, to allow for an external antenna to be connected, but the way I've done it is so the built in twig can still be used at the flip of a switch.

I'd be interested to know if your mod has allowed you to receive any more DAB multiplexes?
My DAB Pure Evoke on whip antenna gets local multiplexes, on an external moonraker antenna
(possibly not best for DAB) all same multiplexes can be heard at stronger signal levels but nothing new.

DAB sound is disappointing like in first post, but at least there's some alternative stations.

hal8000 wrote:

Twistedtransistor wrote:I've done a antenna mod on a portable DAB set, to allow for an external antenna to be connected, but the way I've done it is so the built in twig can still be used at the flip of a switch.

I'd be interested to know if your mod has allowed you to receive any more DAB multiplexes?
My DAB Pure Evoke on whip antenna gets local multiplexes, on an external moonraker antenna
(possibly not best for DAB) all same multiplexes can be heard at stronger signal levels but nothing new.

DAB sound is disappointing like in first post, but at least there's some alternative stations.

Tbh it's something I haven't yet tried, but it would be an idea to take it to the seafront, with my firestik when the conditions are right and see if I can pick up more multiplexes

Currently don't have a DAB radio but thinking about it, ive tried one before and its the more stations on offer that i can't get on analogue FM, birthday soon thinking maybe that, have to see what transpires.

DAB is fine for kitchen and bedroom use, but audiophiles won't like the lossy codecs.

I bypassed DAB and went straight to internet radio because I'm not into music, just speech programmes, so 24kbs/48kbs is just fine. I was a major contributor to the Reciva forum and wiki, but have moved on to more modern devices now, basically an iPod touch about the house and my Galaxy phone for the rest of the time, with 'all you can eat' data plans this is now a real alternative, and with the app I use that encompasses several databases, I can realistically choose from around 60,000 unique stations.
So, to address the question, I don't need DAB thanks.
DAB has missed the boat.