Rick's b.log - entry 2023/01/07

Denver IR-135 Internet Radio - review

It wasn't great, but it worked. That was the most important thing. ☺
However, it did have some problems. For instance, there was no buffering, which led to glitching if the network was loaded. The setup was also rather tedious. A built-in server ought to make things a little nicer. And, of course, the big one was that it only supported http (non-encrypted) streams. Personally, I don't think SSL is justified for streaming radio, on my phone it can be a bit glitchy at times. But, alas, more and more stations are moving to an encrypted connection because "SSL everywhere".

The reason that I haven't looked at resolving some of these issues is because the ESP32 compiler is painfully slow. The most recent firmware was built on my Xiaomi Mi 10T phone, which was quicker than my Pentium 4 box. We're still looking at something in the order of 15-20 minutes to bake a firmware for my NetRadio code. The code is around 64K in size, and it is copiously commented, so really anything over about thirty seconds to run the compilation is... poor.
Quarter of an hour is... poop emoji.

I wasn't ever interested in a commercial internet radio because the last time I looked they were around €100 for a basic model, they were not customisable but could only play stations provided by their back end, and it just so happens that a bunch of them turned into expensive bricks at the end of last year when the Reciva aggregator shut down. Some enterprising people managed to fiddle the settings to point to a fake Reciva server running on one of their computers. But for the masses, it would just sit at startup trying to connect to a service that was no longer present.

Plus, despite the massive wealth of radio stations on the internet, there are surprisingly few NetRadios. Generally looking for this will turn up DAB radios that might support MP3s streamed from the internet. There aren't that many dedicated internet radios.

Around my birthday, I forget the exact date, I thought I'd just look for internet radio on Amazon to see what was on offer these days.

Amazon offered, as expected, plenty of DAB receivers. But lurking in the list was a rather inexpensive little wooden box. By Denver, a Danish company that appears to import and sell a wealth of "Chinese tech" (judging by their website), this box was a dedicated internet radio.
For about fifty euros.

Or to put it into context, a price that wasn't that different to ordering a second ESP32, audio chip, and a nicer display. I had planned to buy those in order to further develop my own firmware without messing with the one I actually listen to.
Or, you know, just buy this thing.

But... there's no point buying it if I can't add my own stations, and there's no point buying it if it can't support encrypted streams. Even if the built in screen/UI and battery were obvious plus points.

Usefully, Googling the model number got me a PDF user guide so I could see that a favourites menu could contain a good few entries (99, to be exact) which could be channels from the SkyTune agregator, or my own stream links.
I sent a quick email to Denver for clarification on the support for https, and they replied quickly. So I ordered it.

Coming in two versions, the IR-135B and the IR-135S, the difference is the colour of the front panel. Silver (the S) or black (the B). Some people might like the silver face. I... really didn't. So I got the black one.

Denver IR-135B internet radio.

Gotta admit, it's got the looks.

I did an unboxing and first use video.

Unboxing

The display

The display can be set to work in one of two modes. The first is "Normal" in which case it'll always be illuminated in the regular brightness level. This might be prefarable if you keep the radio plugged into the AC adaptor.
The other mode is "Dim" where the display shines at the regular brightness level if you use any of the controls, and then dims down to a preset lower brightness after about twenty seconds. This is useful for night use, and also may help (slightly) prolong battery life.

The controls

Internet radio user controls.

The upper left is the power button. Press and hold for three seconds to turn the radio on. Press and hold for about three seconds to turn it off.
If you're running from AC, a simple press will enter sleep mode, where the screen will dim down and show a clock with large digits. Press again to resume.
The time between first pressing the button and hearing a radio station is about eleven seconds (with a five second buffer).

The next button over, that looks like a house, is the Home button. Pressing this will take you to the menu screen. Pressing it again will take you back to the playing screen (you'll also go back to this after about 30 seconds if you don't do anything).
Holding Home for three seconds is a shortcut to the equaliser.

Pressing both Power and Home at the same time is a hotpress for reset. The radio will immediately reboot.

The two buttons below are a Left and Right. Pressing Left will back out of where you are, so you can go backward in the menus. Pressing Right might move into a submenu.
Pressing Right when playing a station will switch views. The detail view has a channel icon (if there is one) plus a report of what's currently playing. The next view simply shows the title with no icon. The next view gives technical information (genre, codec, sampling rate). The next view is the big clock. And the final view is the channel icon, full screen. Pressing again will loop.
Holding either when playing a station will switch to the previous (Left) or next (Right) station in the list.

Over on the other side, the heart button calls up your favourites. And the numbered buttons will directly select the first, second, or third station in your favourites.
Long-pressing one of the numbers will set the current station as the numbered preset. It is NOT recommended that you do this.

Finally, the big round knob. In the menus, rotating it left or right can select menu options or whatever, and pressing it will 'OK' the selection.
When playing a station, rotating the knob will change the volume, and pressing it will stop/restart playback.
When playing a station, holding the knob will add the current station to your favourites list.

That little dot to the upper left of the screen is an infra-red receiver. Without a controller, no comment...

The speaker

In the living room, I plug into the amp to the 12" speakers to crank out something that does justice to metal. ☺

Around back

Internet radio back.

There is a headphone jack for plugging in headphones (and powered speakers). Plugging something into this socket will mute the internal speaker.

The second 3.5mm jack is a line level output for use with amplifiers. As this is line level, the volume control has no effect. Additionally, plugging something in doesn't mute the speaker (but since it doesn't use the volume control, you can simply turn the sound right down).

It looks like Denver is being ahead of the game when it comes to the EU mandate to have things use a common (USB-C) power connector. It was actually a surprise to see USB-C here instead of the typical micro USB, or worse, mini USB.
There's a little LED off to the right. It's red when charging the battery, and green when charging is complete.

Battery

What is worth noting is that the charging is really rather slow. If it'll run for five or six hours, count on charging taking a similar amount of time.
Still, it has a fairly standard 18650 Lithium-Ion cell inside, so it's probably good that it doesn't try to sling a full charge into it in half an hour like some smartphones try to do.

WiFi

Associating with WiFi could be a trauma due to how you enter characters one at a time, if you have a long password. You do, right?
There is a WPS mode for easier pairing, but I trust that everybody reading this blog has had the good sense to disable that glaring security hole.

Which leaves... a little app called Esptouch that you can obtain from the relevant app stores. Run this, enter the password for the selected access point, and then select Broadcast if you're on the same access point and frequency, or Multicast if you're on a different access point (on the same network!) or are connected using 5GHz (the ESP32 only does traditional 2.4GHz WiFi).

Set up the radio by choosing "Add AP (SmartConfig)", and when that's waiting for data, prod the "Start" button on the app. After a few moments, the radio will pick up the connection details for the access point.
Doing it that way was pleasantly simple.

Note: There may be additional complications at this point if your network is set to reject unknown MAC addresses and/or there's a button to push to allow associating a new device. This is the prerogative of your network, and not under control of the radio.

The radio remembers access points. I'm not sure how many, as I only have two. It's smart enough to filter out non-access points such as direct connections to printers.
It won't switch access point to pick the one with the best signal. This behaviour can be a blessing and a curse. A blessing because it can always keep you connected as you move around the house, but a curse because in the case of Android, it isn't smart enough to filter out non-APs (like printers!) unless you specifically set "Don't autoconnect".
So, then, this radio won't switch APs automatically. But it's not hard to switch manually. It remembers the password, so all you need to do is choose it and it'll connect.

The UI

The main menu.

Turning the knob selects from one of the following:

• My favourite - favourites list
• Internet radio - choose a Skytune station
• Media centre - play music from a NAS or other share
• Bluetooth - becomes a Bluetooth speaker
• Alarm - set up two possible alarms
• Sleep timer - set the radio to automatically turn off
• Configuration - set everything up just as you want it

Since taking photos of the display would make your eyes bleed because of the clash between LCD panel and high resolution camera... I took a couple of days to reproduce the character set used and then threw together some BASIC code to more or less reproduce some of the displays. It's not exact, but it's close enough.

So let's take a look at all of this in turn.

My favourite

Favourites.

Wobble the knob to choose a station, press the knob to begin playing.
Remember, the buttons 1, 2, and 3 will immediately play the first, second, and third stations.

Oh, and a big thumbs up for spelling "favourite" correctly. ☺

Pressing the Right button will allow you to edit the current entry - move up, move down, delete, move to top, and move to bottom.

Internet radio

Going via Skytune (first option), you can choose Local radio (by detected country), Globe most popular, all, by genre, or by region.

Don't choose Globe all. There's a mere 33,486 stations to scroll through!

By genre asks if you want music or talk-based. Following this, a detailed but rather eccentric selection of genres to choose from.

You can see this for yourself. Just go to http://skytune.net/.
If order to choose a radio station, click/tap on the heart icon. You can then choose if you want to play it or add it to your favourites. You must then enter the radio's IP address. This is used by some script on the page to generate a special URL that the radio understands. For example, to play BBC Radio 6, it would send http://192.168.1.31/doApi.cgi?SL=EN&AI=129 and voilà, the radio begins playing something a lot more sedate than my usual selection. ☺

Looking by country is first subdivided by continent to make the list easier to manage.

You can also search, either containing, begins with, or ends with. Once you've chosen how to search, it will come time to enter something to search for.

Searching.

The white letters in the middle can be shifted by rotating the knob. Press the knob to accept the chosen character, and hold the knob to begin searching.
It's fiddly, but not impossible. Here I have entered mom's birthplace.

The results come back quickly.

Search results.

Choose a station and prod the knob to begin playing.

You might have noticed the shaded top of the search dialogue said "1/4", implying there are four entries in the menu.
So if there are three search methods (contains, begins, ends) what's the fourth thing? Usefully, it's a history so you can easily recall past searches without having to enter the information all over again.

Media centre

Interestingly, it asks you if you want to look at video, music, or photos. It's not capable of playing videos or displaying photos so I wonder why they didn't just disable these menu options?

Playing MP3s seemed to work without problem, and it even picked up on embedded album art.

However, playing M4A files (such as downloaded from YouTube) crashed the radio. After a few moments it would reset itself, try to play the file, crash, reset, and so on in a loop.
There are two ways to resolve this situation. The first is to dismount the media so the file is no longer accessible, or hammer the '1' button as it starts up and if you time it right, it'll start playing favourite #1 instead of the music it can't cope with.

Bluetooth

Bluetooth.

Oh my god, I've just noticed that my Mi 10T also sends track information. Nice. My Samsung S9 doesn't, and I've often wondered if it was possible.
Oh, even better. With CustomRadioPlayer for streaming radio, it sends the channel name followed by the track name. Very cool.

Note that you cannot do anything else with the radio (like use the menus) when it's running in Bluetooth mode. I'm guessing the codec handling takes a lot of processor grunt? Probably does it in software rather than hardware (like dedicated speakers).

Alarm

Sleep timer

As I write this, WZBA is playing "Sweet Child of Mine". Not exactly sleep inducing. ☺

Configuration

Configuration.

Network allows you to select if WiFi is always on, or if it turns off after 30 seconds of not being used (like if you're in Bluetooth mode). This can save power when running on battery, but it will make it take slightly longer to play a station.
You can also select what channels are available (1-11 USA, 1-13 EU, 1-14 JP/CN), and of course add and manage access points.
If you need to change the current access point used, this is where.

Choosing an access point.

Date and time is for setting your timezone (automatic or manual), the format (12/24hr), the date format (dd/mm/yyyy or mm/dd/yyyy - sadly no yyyy/mm/dd), and whether or not to use network time.
If you don't use network time, the time will blink "00:00" every time you turn the radio on. I can't imagine this is particularly useful, but it's there in case you want to have to set the time yourself like you'd do with your microwave...

Setting the date and time.

Language allows you to choose what language you want the UI to be in. German, English, Spanish, French, Italian, Dutch, Polish, Russian, Czech, Hungarian, Slovenian, Romanian, Croatian, and Chinese.
A rather peculiar selection, given that Denver is a Danish company. I'd have expected Danish, Swedish, etc to be in there somewhere.

Local radio sets the home country. It can be automatic, or you can choose (continent, then country).

Playback setup is for network shares. Repeat all, Repeat one, Shuffle, or Normal.

Resume play selects whether to resume what was previously playing once it's ready, or if the radio should start up in the main menu.

Dimmer sets how the screen should behave, and what brightness level (5%-100% in 5% steps) to use for normal and dim modes.

EQ lets you choose or define an equaliser option. You may find "Rock" helps boost the bass a little if using the internal speaker, but if you're using anything else, it's best to leave the EQ flat. The music you're listening to has already been mixed to sound its best (or, at least, how it is supposed to sound - one could argue about a lot of CD mixes, but I digress).
Really, the only need for a custom EQ is to cater for deficiencies in your setup.
The available equaliser defaults are: Flat (none), Rock, Jazz, Pop, Classical, Dancing, Heavy metal, Disco, Live, Soft, Hall, or Advanced.
In Advanced, you can set up the preamp gain (-18dB to 0dB), then set five frequency bands to a value from -12dB (cut) to +12dB (boost). The frequencies are 105Hz, 300Hz, 850Hz, 2.4kHz, and 6.9kHz. A rather strange selection of bands. 105Hz is bass, use sparingly. 300Hz and 850Hz are low mids, a lot of instruments and male vocals can be in here. 2,4kHz is the high mids. Synths, percussion, and female vocals are here. And finally 6.9kHz is the upper range of "presence".
Generally, in order to avoid distortion, if you want to boost a specific frequency band, it might be better to cut the others.
Finally, you can set up the 3D depth from 0 to 100% to enhance stereo separation. This uses some boosting, so you might need to cut some preamp gain in order to avoid distortion.

Setting a custom EQ.

Buffer time lets you specify if you would like the default two second buffer, or the more resilient five second buffer. The larger buffer means it'll take longer to start up but if it glitches using a two second buffer, this ought to fix that unless your connectivity is really shonky.

Information will show you Network information - this is where you can discover your radio's IP address - and system information (version numbers).

Software update will check to see if there's updated software to install. My app version is 20211110.1013, which looks awfully like just before quarter past ten on Wednesday, 10th of November 2021.

Finally, you can Reset everything to factory defaults.

But, usually, what you'll see is something like this:

Playing a station.

Problems

Setting presets 1-3

Organising stations using the web interface

Thankfully there's a way to download the database (seems to be encoded as base64, but unpacking it results in gibberish - some sort of compression?) and I used it a lot. Of course, I'm trusting that uploading the database actually works. Not tried it.

Suffice to say, the channel manipulation "needs work".

USB-C

Adding stations

Choosing a country is tedious - plus I had to run IP lookups on some of my stations in order to know where the hell they were. Bollocks Radio comes from Mexico. Who'da thunk?
But choosing the genre is made of fail. The list is broken, it sort of follows the peculiar Skytune genre list until it gets to "Office" and then it just gives up.
No, really, it's broken. I pulled the pile of JavaScript apart to find that http://192.168.1.31/php/get_CG.php was the URL to retrieve the country list and the genre list. Oh, and no, I seriously doubt the ESP32 is really running php, it's neither powerful enough nor has enough memory onboard to manage that. But it can respond to whatever URLs are requested. Call it whatever you like.

Accordingly, I tend to classify mine as "Legends" (metal) or "Nostalgia" (80s).

Alarm usefulness?

To put this in conext, I have three alarms to wake me up. My phone alarm sounds at 7.10am. It will sound again ten minutes later. And ten minutes after that, a different (older) phone (my S5 Mini) will sound. And that's in a different place, so I have to be up to turn it off.
I'm usually awake by about quarter to seven, but I'm paranoid that one day I might actually get a good enough sleep that I don't wake up on time.
Hasn't happened yet, but there's always a first time, right?

5GHz

Media playback

Stereo separation

Now what I like

Wide choice of radio channels

Automagic control of stations

Responsive controls

A built-in speaker...and battery

A UI that doesn't suck

And, whoever did this, a big thank you for using British spellings (such as favourite and centre instead of favorite and center).

A clear display

Anyway, it's currently playing. At a glance I can see WiFi strength, battery status, running on AC, the time (good god, half ten already?), the channel, the current song name, and how long I've been listening.

3.5mm sockets

That there is an EQ

Easy on the eye

Compatibility

Future proof

No favouritism

It generally just works

Okay, it isn't perfect. You're not going to get perfection for fifty euros.
But for what I paid, it is actually better than I expected.

I'm pleased with this.

Yeah.

I know.

Mind blowing.

I've actually bought a gadget that I didn't spend half the review taking the piss out of because it was such a disappointment.
Do you have any idea how many times I've written words to the effect of "seems like reasonable hardware let down by firmware so awful I can only surmise that the developers have never actually used their own product"?

Not in this case.

For fifty euros, this thing is actually pretty... good.

There.

I said it.

Now I need to go lie down. ☺

Actually, I need to eat. It's ten past eleven at night and I've not eaten anything today. So please excuse me not checking this blog post. Need to eat, then enter Standby mode myself.

Your comments:

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Anon, 8th January 2023, 00:37

50 euros is about £44. So I took a look on Amazon. On the UK site it's being sold for £70. Nearly double the price. Rip-off Britain, again. (Not my fault, I voted Remain.)    What's the audio quality like? How does it compare with, say, a Squeezebox Boom, Tivoli One or Pure Digital One? (The latter two are DAB/FM radios which include internet and DLNA streaming functionality.) The Tivoli and Pure are both mono speakers, but one of them (I think the Pure model) has an optional extension speaker, which gives stereo when connected. (The Squeezebox has 2-way bi-amped stereo speakers and pushes out 75W/channel, 50W to the bass/mid and 25W to the tweeter.)    Was tempted to get one like yours anyway for a fiddle around at £44, but £70 is a bit steep. If it supports DLNA then it'll play my local music, Squeezebox server also provides a DLNA music source.

David Pilling, 8th January 2023, 19:00

Seems unusual - as in you are currently top of Google for this model. It looks like the kind of project people do for themselves, made into a product. I couldn't find anything else exactly like it, normally you'd expect to find the same thing under various names.  Everything I could find had DAB or FM as well.

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