DAB in Ireland: RTE multiplex closed

I agree, 256K MP2 should be fine. Satellite used to mostly use that for Radio. But many are now much lower.

128K is stupid. Quality falls over a cliff with MP2. It's not as progressive a loss as with AAC.

I found no advantage with 320K MP3 over 256K MP3. But the actual CD was still slightly better but only on certain material.

lawhec

watty wrote: »

No, I use 256K MP3 for my own CDs on my MP3 player as a minimum.

As far as I'm aware, at 256kbps with a good encoder, there's no significant difference for most people listening to music at this bitrate (constant or variable average) between MP2 and MP3. On some occasions, MP2 might actually be slightly better in some cases. That's because MP2 was designed for use at bitrates between 224kbps (VCD audio) and 384kbps while MP3 was designed to offer better quality at lower bitrates (< 224kbps) compared to MP2. Using higher bitrates for MP3 often delivers no noticeable increase in quality for most music beyond about 192-224kbps because of the way the coding algorithms are applied though the difference for the likes of classical music can often be noticed. Many broadcasters still use MP2 for their internal use or for transferring audio works to others.

My own personal preference is for FLAC for original copies and transcoding, MP3 192kbps VBR or Ogg Vorbis 160kbps VBR for most music while for heavy compression where space is a premium, 48kbps HE-AAC or Ogg aoTuV VBR. Speech material can often use lower bitrates with less complex material and also reducing the sampling rate without any real quality loss e.g. 24kHz over 44.1 or 48kHz.

lawhec

The main problem with DABv1 as it currently stands is that it's mid-90's technology that by todays standards struggles against better codec algorithms and transmission coding methods. The BBC switched on their first DAB transmitter from Crystal Palace in 1995 and at the time they had just four stations on as a trial - I think they increased it to six later. Trial listeners who had an opportunity to take a listen on a commissioned bus with receivers & headphones on board were supposed to be very impressed. Similar tech of its age in the form of DVB-T or DVB-S with MPEG2 video & MP2 audio still continues on to this day because it was adopted quickly and was cheap for consumers to buy receiving equipment.

Of course as a few years started to develop later on the final DAB standard wasn't fully set and perhaps a chance to use MP3 over MP2 was missed. The first receivers cost a bomb to buy which didn't help. Digital 1 came on, but no one was listening. Stations specially commissioned for it in due course shut down over the next few years. That in particular brought in the eventual case of starting to shunt in more stations at the expense of audio quality. However as new, cheaper DAB sets started to appear they were mainly of the single-speaker kitchen work top kind - the drop in bit rates generally don't be noticed.

Power to run a DAB radio is another problem. Not a huge concern for home and car systems, but quite a bit more for portable listening when you can't connect to a mains outlet. Advances have been made, but still not close to analogue power levels.

The point about London is fair and a good reason why DAB is popular there - the state of unlicenced transmissions there can often mean trying to listen to a legit station on a random area can be hit and miss especially with unlicenced stations often being parked only 0.2MHz from licenced stations. A few years back LBC switched their main FM (97.3MHz) transmitter to being mono only to help combat interference from an unlicenced transmitter on 97.1MHz. The FM broadcast radio band in London remains chaotic because of them.

I've never heard of a DAB pirate station. I suppose it could be technically possible for them to do it, but getting a competent installer to ensure it was set up properly could be a challenge, rather than a group of runners breaking through the service door of a tower block to attach a transmitting aerial to a dodgy piece of scaffolding (or occasionally a mobile mast or even a communal TV aerial mast) while hooking the transmitter up in a hard-to-find spot using siphoned off electricity, normally from the lift or a service supply. One possible advantage for them however would be the SFN possibilities - while some pirates have FM transmitters broadcasting on the same frequency from several sites (often by using a timer to switch on and off to reduce co-channel interference), properly setting up a SFN'd multiplex using several sites would require busting all sites to take the multiplex off the air. Using triangulation to take out unlicenced transmissions would be a much more time-consuming task. However the main thing that stops DAB pirates in London, apart from trying to reach listeners, is the nature of many of the pirate stations themselves.

As one person mentioned to me, on a commercial (licenced) DAB multiplex the bitrate of each station would be determined by money. On a pirate DAB multiplex it would be determined by guns! :eek:

No, I use 256K MP3 for my own CDs on my MP3 player as a minimum.

The Pirates can easily use DAB. They don't as the battery life would be too poor for the mobile listeners getting coded Drugs info and too few of their regular audience uses DAB.

Mearings wrote: »

Noted yesterday Lyric fm streaming at 160kbps mp3, an improvement.

Still not good enough for orchestral works, I am sure you would agree.

Capt'n Midnight wrote: »

If you are at home you could get better sound quality from saorview / satellite / internet - unless they hobble it.

Flip between Freeview and Freesat radio using DVB Viewer if you can, Freeview radio is much more processed in the chain. BBC stations via the internet are AAC.

Capt'n Midnight wrote: »

DAB is a solution in search of a problem.

What is it's niche ?

What can it do that can't be done on existing networks ?

It does have one use.

If you are in a huge city like London that is plagued with interference from surrounding areas and pirate stations it can give stability. (Until the pirates work out how to broadcast on DAB!) Loads of waveband to accommodate any number of stations. Except they have squeezed them all in at silly bitrates instead. Its a farce. :mad:

Mr. Rabbit wrote: »

I do have a Watson folded dipole on the chimney (35 ft) and I can't get anything from that either, so there's no point in trying anything else.

I think that is fairly conclusive too.

Mr. Rabbit wrote: »

If Digital One aren't going to avail themselves of the new capacity on DAB here, maybe RTE should think about it, especially now that RTE Radio One is gone from Medium wave ?

Anyones guess what will happen given the economy is not great at the moment.

The thing about RTE Radio One going from MW to LW is the same as with BBC Radio Four. Both are part of the national 'resilience plans' to keep people informed during times of severe bad weather in each country. Not a very good move as most oem car radios have MW but many don't have LW and yet most aftermarket radios have FM MW LW. And oem DAB car radios are all over the place with other bands. So much for getting a local weather forecast in the sticks when there is a sudden snowstorm coming up that is going to dump two feet of snow on your car and a power cut if you make it home. :rolleyes:

Capt'n Midnight

Mearings wrote: »

Radio sound quality for most stations is better on internet radio than on dab.

If you are at home you could get better sound quality from saorview / satellite / internet - unless they hobble it.

If you are in a car sound quality isn't really that much of an issue because of the background noise, and in areas of poor reception you have RDS and fail back to mono, or even LW if all else fails.

Does DAB provide any RDS features - like alternative frequencies and traffic announcements ?

As for portable usage a smartphone can provide internet streaming in a box you already own. Many also have FM radios. Again background noise will cancel out a lot of the quality arguments.

DAB is a solution in search of a problem.

What is it's niche ?

What can it do that can't be done on existing networks ?

dvb-t better there. but quality of the dab and dvb-t is terrible.

The content of Gold I find poor too.

Where

Jordanstown Co. Antrim.

An ERP of just 5kw and the wrong side of the mast would explain the lack of a signal. I do have a Watson folded dipole on the chimney (35 ft) and I can't get anything from that either, so there's no point in trying anything else.

If Digital One aren't going to avail themselves of the new capacity on DAB here, maybe RTE should think about it, especially now that RTE Radio One is gone from Medium wave ?

Still, I suppose I can get it from Clermont Cairn via Saorview now with the increase in power last week.

I quite like RTE Gold, even if there are no presenters on it.

Mr. Rabbit wrote: »

Is there any reason why the Clermont Cairn RTE DAB test transmissions are so weak at this location ?

Where

Mr. Rabbit wrote: »

Like Digital TV from that location prior to the 24th October I've excellent analogue receotion , but nothing in the way of DAB.

I take it the RTE multiplex isn't DAB+ ?

What's the E.R.P of the Clermont Cairn DAB transmitter ? I assume it isn't nulled to the north ?

I think it is 5kW. Only the commercial test uses DAB+. The write ups imply the broadcast array is on the south side of the mast and it could be regarded as a waste of electricity money to transmit anywhere other than towards the greater Dublin area. Due to the type of mast leakage out the back may be minimal.

If you are any distance and not on top of or on the facing side of a hill you may well need a 3 to 5 element vertically polarized VHF Band III aerial. Due to the propagation characteristics of Band III, chances are you would get away with having this in the attic if you get an aerial with 2 elements more than used outdoors. Most attics have enough space for it vertically polarized. Loads around, no point in getting a 'special' dab aerial.

If you want to know if you should get it, get a portable dab set and either take it upstairs to a window facing the transmitter or if a one storey house take it up a stepladder in a place in the garden that has a clear line towards the transmitter. That will give an idea of field strength.

Is there any reason why the Clermont Cairn RTE DAB test transmissions are so weak at this location ?

Like Digital TV from that location prior to the 24th October I've excellent analogue receotion , but nothing in the way of DAB.

I take it the RTE multiplex isn't DAB+ ?

What's the E.R.P of the Clermont Cairn DAB transmitter ? I assume it isn't nulled to the north ?

160k MP3 is FAR better than the junk bit rates of MP2 on DAB & DTT they are using. Yet for same number of listeners that would cost 1000s of times more!

Mearings

Noted yesterday Lyric fm streaming at 160kbps mp3, an improvement.

Mearings wrote: »

Radio sound quality for most stations is better on internet radio than on dab. RTE has changed to mp3 on internet radio, whereas the original speed for Lyric fm was 192kbps, this has now been reduced to 96kbps. This is a very inferior sound for a classical music station.
I queried the change with rtenltech@rte.ie, so far (18 days on) my email has been ignored.

Having a classical music station in MP3 at 96kbps is beyond reason when it could be in AAC at 192kbps.

Charles Slane wrote: »

Digital Broadcasting will add two new channels by the end of November.

"As we continue to work on aspects of content licence issues that have arisen in the past months we are delighted to announce today that two definite new services will broadcast on the trial before the end of November"

http://www.dbdb.ie/q3-2012-report/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+dbdigitalbroadcasting+%28DB+Digital+Broadcasting%29

Did you see these gems on their Twitter?

their Twitter feed wrote:

All DAB+ service's bit rates have been increased - from 48k to 64k AAC+

some days later

their Twitter feed wrote:

We think 32k Parametric Stereo on Ri-Ra DAB+ sounds as good as 128k Joint Stereo on Ri-Ra (regular DAB). Your feedback appreciated.

The 128kbps Joint Stereo is MP2 not even MP3 so it doesn't have any of the improvements of MP3 and is at best equivalent to a 96kbps MP3 with added raspy bits.

Despite the progressive improvement on filter banks and sampling methods once the signal has been strangulated and processed to death and squashed to 32kbps its still going to sound like something rattling in a tin can. Even with AAC. And I strongly suspect that AAC 32kbps Parametric Stereo was actually intended for DRM on AM medium or long wave where the channel bandwidth is narrow and not intended for DAB+.

Please someone take these raving lunatics away from anything to do with DAB+ :mad:

More Music wrote: »

That isn't their Twitter. The Twitter feed of the company you quoted have nothing to do with Lyric FM, RTE or RTENL.

I did the quotes by hand so one has obviously fallen out changing the sense of the post i.e. two separate providers but with the same diabolical mindset.

I'll post it again, this time as it was meant to be.

The EBU tests demonstrate that MP2 persistently causes annoyance even at the highest bitrates because the filtration and sampling stages are more primitive than MP3 or AAC, or AC3 which is often included as a comparator since it is used with HD broadcasts and some continental SD broadcasts.

I find that AAC captures timbres much better than higher bitrate MP3 due to the many improvements.

AC3 is very dependent on the encoder, more so than the decoder. Recent encoders have audible developments over older versions at the same bitrate.

I mostly use FLAC and only use MP3 when I am forced to by portable equipment.

When switching between MP2 and AC3 sound on satellite broadcasts (via DVB Viewer) the difference is painful. Further, the terrestial Freeview radio stations sound worse than satellite, if you flip between them with DVB Viewer it is clear they go through more processing stages.

MP2 is obsolete regardless of bitrate and is fit for the bin.

The 'blind' tests done by and for the EBU indicated that at low bitrates MP2 should use a much higher bitrate than 2 times the HE-AAC bitrate.

Yes, but by that stage the quality is pointless anyway. I agree, as the bit rate is lower AAC and then HE-AAC is even more saving and at high bit rates less advantage. I suggested that earlier.

Unless they are trying to use DAB as a replacement for AM Radio, such low bitrates are pointless. Even then if you have a good AM signal, then frequency limited sound is more pleasant than the artefacts in low bit rate Digital.

What is the total HE-AAC bitrate for same as 256K MP2 for a wide range of music?

How does 256k MP2 compare with 256K MP3 (all my MP3s are 256K).

reslfj

watty wrote: »

64K AAC+ is about the same as 128K MP2

HE-AAC - does improve audio quality over AAC for lower bitrates (below ~96kbps I think). The 'blind' tests done by and for the EBU indicated that at low bitrates MP2 should use a much higher bitrate than 2 times the HE-AAC bitrate.

Now in DAB+ a nominal 64 kbps channel is used as 1/12 ReedSolomon FEC and 11/12 HE-AAC audio i.e. the HE-AAC effective bitrate is just 56.666 kbps.

Lars

Mearings

More Music wrote: »

The email contact for RTENL is rtenl@rte.ie

I originally complained to Lyric fm who did reply:

<<I have sent your query to our engineers and will revert with reply>>

At present I am listening to Linn Jazz at 320kbps mp3 on a Roberts WM 201 internet radio. The sound is near cd quality.

Richard wrote: »

They do plan to.

http://www.ukdigitalradio.com/coverage/postcodesearch/nireland.asp

Yes, so I gather but when ?

There's no reason now for NI not to have Digital One

More Music

jeltz wrote: »

Having a classical music station in MP3 at 96kbps is beyond reason when it could be in AAC at 192kbps.

Did you see these gems on their Twitter?:

That isn't their Twitter. The Twitter feed of the company you quoted have nothing to do with Lyric FM, RTE or RTENL.

More Music

Mearings wrote: »

....This is a very inferior sound for a classical music station. I queried the change with rtenltech@rte.ie, so far (18 days on) my email has been ignored.

The email contact for RTENL is rtenl@rte.ie

64K AAC+ is about the same as 128K MP2 AND BOTH ARE AN INSULT given the cost of the radios.

What is needed is 2 channel:
192K(RTE generally) to 256K (lyric, RnaG) MP2
128K for RTE1 Extra Mono

Note at the higher the bit rate the less advantage AAC is to save bit rate. AAC not a 1/2 saving at those qualities.

NO Joint Stereo. It only works for true binaural or natural Cross cardioid mic live Stereo. Anything else need real separate channels.

These people are just greedy wanting to pack in too much per Mux. The Mux are 1/4 the spectrum of a DTT mux. It's not lack of spectrum, just greed.

If it makes DAB too expensive to give it decent quality, then PLEASE don't bother.

Mitch epitag

Why should ireland spend a red cent rolling out this dinosaur technology that has never really taken off anywhere ?

Mearings wrote: »

Radio sound quality for most stations is better on internet radio than on dab. RTE has changed to mp3 on internet radio, whereas the original speed for Lyric fm was 192kbps, this has now been reduced to 96kbps. This is a very inferior sound for a classical music station.
I queried the change with rtenltech@rte.ie, so far (18 days on) my email has been ignored.

Having a classical music station in MP3 at 96kbps is beyond reason when it could be in AAC at 192kbps.

Did you see these gems on their Twitter?

their Twitter feed wrote:

All DAB+ service's bit rates have been increased - from 48k to 64k AAC+

some days later

their Twitter feed wrote:

We think 32k Parametric Stereo on Ri-Ra DAB+ sounds as good as 128k Joint Stereo on Ri-Ra (regular DAB). Your feedback appreciated.

Richard

Mr. Rabbit wrote: »

With ASO now complerte in the ROI, there's no reason why Digital One can't broadcast in NI.

They do plan to.

http://www.ukdigitalradio.com/coverage/postcodesearch/nireland.asp

With ASO now complerte in the ROI, there's no reason why Digital One can't broadcast in NI.