HD radio

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<SLV>

Ground Beetle
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Our local public radio station offers HD channels, and one of these is 24-hour classical music (interrupted by 5 minutes of propaganda at the top of each hour). My wife really enjoys the station when we are riding in my car, and she said she would love to have an HD radio in the house. Thing is, I can't find any quality bookshelf systems with HD radio. There are tuners for home stereo systems, but I was thinking something less complicated, smaller, and cheaper. Even the Bose Wave radio doesn't have an HD tuner (what?).

Because there are relatively cheap car decks with HD radio, I was thinking about going that route and maybe making a cabinet for it. Anyone ever done this? I have some experience building custom speaker boxes, so I know how to get good sound. But I am wondering about converting to 12vdc.

I appreciate suggestions and recommendations.
 
I've seen guys run auto systems in custom boxes indoors powered with a battery. My crude approach would be a deep cell battery that you can stick a float charger on. Could build an enclosure with an open back near an outlet. Can easily run speakers to hearts content.
 
I bought a car stereo 50 years ago, had it on a footlocker with a 12v car battery and speakers. Worked great. Nothing much has changed.
I have a rig I made up for testing car audio, I bought a cigar lighter port that plugs in the wall, converting house to car.
Then I have a cigar lighter plug that terminates in bare wires which I hook to the component I want to run or test.
I don't see why you can't build a box and put it in.
One idea is to use a old PC power supply, there are 12v rails on them. Even get a fanless one if you need quiet.
Best would be the modular type that allows unused rails to have the wires removed.

ps I bet if you searched utube there are many vids on it.
 
I'm fairly tech savvy and I had no idea there was HD Radio!

Get a radio


This was interesting

HD Radio (HDR)[1] is a trademark for an in-band on-channel (IBOC) digital radio broadcast technology. It generally simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD Radio is used primarily by AM and FM radio stations in the United States, Canada, and Mexico, with a few implementations outside North America.

The term "on channel" is a misnomer because the system actually broadcasts on the ordinarily unused channels adjacent to an existing radio station's allocation. This leaves the original analog signal intact, allowing enabled receivers to switch between digital and analog as required. In most FM implementations, from 96 to 128 kbps of capacity is available. High-fidelity audio requires only 48 kbps so there is ample capacity for additional channels, which HD Radio refers to as "multicasting".

HD Radio is licensed so that the simulcast of the main channel is royalty-free. The company makes its money on fees on additional multicast channels. Stations can choose the quality of these additional channels; music stations generally add one or two high-fidelity channels, while others use lower bit rates for voice-only news and sports. Previously these services required their own transmitters, often on low-fidelity AM. With HD, a single FM allocation can carry all of these channels, and even its lower-quality settings usually sound better than AM.

While it is typically used in conjunction with an existing channel it has been licensed for all-digital transmission as well. Four AM stations use the all-digital format, one under an experimental authorization, the other three under new rules adopted by the FCC in October 2020. The system sees little use elsewhere due to its reliance on the sparse allocation of FM broadcast channels in North America; in Europe, stations are more tightly spaced.
 
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I picked up this Kenwood head unit today (Marketplace) for $40. Has HD radio, CD, and includes a remote! Never installed.

Watched a few YouTube videos on making it into a radio. Not too hard. Just need to find a 12v DC power supply. I see that printer power supplies might work.

Debating how to finish the project. I could:

1. Get some used bookshelf Speakers, or...
2. Pick up a pair of 5.25in RF 2-way drivers for $40, and...
3. Build speaker box(s), or...
4. Install in wall/ceiling in kitchen (where she spends most of her time either baking or crafting at the kitchen table).



 
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Another option may be to hook it up to our TV soundbar. It has a nice sound and powered subwoofer.
 
Also, we don't get good reception because of the hills around us, so I am planning on connecting the antenna to the house electrical ground. Planning on fusing this connection in case ground is energized, but not sure what size fuse.
 
<SLV> said:
But I am wondering about converting to 12vdc.
Click to expand...
Get a 12v transformer.

You might already have one. Any power cord with a brick on it that outputs 12vDC would likely work.

Or get something like this, cut the plug off the end of the wire and connect it to the power leads on the radio.

 
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Joe King said:
Get a 12v transformer.

You might already have one. Any power cord with a brick on it that outputs 12vDC would likely work.

Or get something like this, cut the plug off the end of the wire and connect it to the power leads on the radio.

Click to expand...
I have several. But they are either 18-19v or 0.8 Amp 12v. Need to find something about 10 amps in the 10-16v range (12v nominal). I have read laser printer power cords are ideal.
 
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<SLV> said:
I have several. But they are either 18-19v or 0.8 Amp 12v. Need to find something about 10 amps in the 10-16v range (12v nominal). I have read laser printer power cords are ideal.
Click to expand...
If you have an old desktop no longer in use, could use that power supply:

Power Supply | 16 Amp Power Supply - 110 volts to 12 volts

Buy the Best 16 Amp Power Supply from $26.99. Oznium 12V Adapters: It plugs into a 110 volt wall outlet and lets you power up to 16 amps at 12 volts.
www.oznium.com
 
<SLV> said:
Another option may be to hook it up to our TV soundbar. It has a nice sound and powered subwoofer.
Click to expand...
I'd be careful doing this...

The HD receiver 'probably', as in most likely has an amplified output to speakers. Your sound bar input might not like power coming in?

Think about this:

Soundbar has 'low signal' from TV in and 'high signal' aka power out to speakers.

HD radio has 'low signal' from the ether (antenna) and 'high signal' aka power out to speakers.

You don't put power into a low signal input.

They won't play well together. You could damage the soundbar.

these would sound pretty good. $99

Moukey Passive Bookshelf Speakers (Pair), Peak power 110 Watt​

 
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It has preamp outputs.
 
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Tested the theory of using the house electrical ground by connecting it as a TV antenna. Results were moderate (6 channels). Then I connected the TV antenna to the i-beam that runs the length of the house. It is also connected to a second i-beam on the other floor by a steel post. These results were superb - 26 channels!

Not sure how much of this carries over to FM, but will find out.
 

Do you have an attic? I threw up an antenna in one for a house before, worked well.
 
<SLV> said:
Just need to find a 12v DC power supply.
Click to expand...
I bought this 3.5 years ago for my 100w ham radio. It is rated 12v (adjustable) and up to 30 amps. $20
 
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Someone_else said:
I bought this 3.5 years ago for my 100w ham radio. It is rated 12v (adjustable) and up to 30 amps. $20
Click to expand...
I appreciate the suggestion, but I am going to look for an external unit with about 10a capacity. It will be silent, and make for a smaller radio cabinet.
 
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<SLV> said:
but I am going to look for an external unit with about 10a capacity. It will be silent, and make for a smaller radio cabinet
Click to expand...
One like I linked to? External brick-type on the power cord. 10A.
 
You can probably find the app on Fire Tv or Google Tv.
 
Picked up this new pair of 6 3/4in 2-way speakers today for $30. (Marketplace)

I am in $50 so far. Going to order the AC adapter next (can't find anything around me).

I would like to find a powered sub that I could Integrate into the cabinet I'm planning to build. Haven't found the right one yet. I would like to keep the entire build under $100 if possible.

 
You could build your own sub if you have materials left over from your house build?

Doesn't that HD radio output power already?

Need an 8" speaker

bigger speaker means bigger box means more material.

Subwoofer Box Calculator and Subwoofer Box Design

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or you could buy this for $84
 
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Yeah, I think a single 8in sub (dual voice coil). Run the rear channel of the head unit directly to the sub with a 150hz low pass filter. Then bass filter the speakers at 150hz. Classical music at the volume it will be used shouldn't require much power.

Can get this one from Crutchfield for $60.

 
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Also, having the sub on the rear channel makes it so I can balance the bass simply by adjusting Fade on the head unit.

By running a dual voice coil driver I can double the power to the sub by sending the left and right rear channels to each voice coil. Might end up with some distortion because the signals aren't identical, but at less than 150hz I would expect it to ge negligible.
 
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Viking said:
Did Crutchfield guide you on the wiring for speakers?
Click to expand...
I chatted with a tech on it. She said no low pass filter was needed because the sub won't respond above a certain frequency.

Should be OK on impedence because the voice coils on the sub are each 4 ohms as are my front channel speakers.

Planning on a sealed enclosure. Specs say minimum box volume of 0.5 cu ft.
 
My church is discarding an old Vose upright piano. I am going to disassemble it and use the wood to build the radio cabinet. It is veneer over solid board. I hope to be able to cut it without chipping up the veneer on the edges. I will touch up the existing finish and add a coat of satin poly.

 
Sweet! Now that is a great use of recycled wood! You could even build the subwoofer box out of that.

If you can and it has a sound board, grab that as well. That will be straight grained spruce and good for guitar sound boards etc. Really dried out too if it's an older piano.
 
Here is what I'm thinking for the radio cabinet. It will be 11.5in tall, 24in wide, and 14in deep. The subwoofer will be sealed (and filled with fiberglass), and to increase the volume above the 0.5 cu ft requirement I have included the area above the head unit. The speakers will have ports to the cavity that is housing the head unit. The slots above and below the head unit are for ventilation (cooling). The speakers should aid in air flow -- acting like pumps above the head unit to push out the hotter air.

Not sure what wood I will use for the top and bottom, but I am thinking about painting it for contrast with the wood. The top will have hidden fasteners and be glued and caulked. The bottom will screw on with a gasket for service access.

Still researching the antenna. I robbed a Motorola plug off a junk car. I am really curious to try tying into the power supply ground to access the house wiring as an antenna. For peace of mind I will add an inline fuse... something very light since the antenna should not be carrying measurable current.

 
On the space above the head unit I would like to mount the Piano branding / info tags. Sort of a tribute to the donor instrument... and a vintage look.

FYI... up to $110 on this build. Rest of the cost should be minor incidentals (like wiring fittings, screws, glue, etc.). Planning on using scrap/salvage wood for the cabinet.
 
If you port the sub I'd put it in back high up so it could vent the heat - if any. The plans I posted give the dimensions of the tuned port. All one need do is replicate the internal area and length of the port for a .05 cu ft box.

You may need the resonant frequency of the sub speaker to calculate the port? I know on an EV SRO12 speaker I have I had to have that Hz to calculate it. Manufacture specs should list that.

Don't forget to include handles!


edit to ad: You could put the port in front as well. Just a slot across the top with a baffle for length? It would hardly be noticable.
 
I prefer a sealed sub. Tighter response with less distortion. Better response at all frequencies (whereas tuned port favors the frequency it is tuned at). Smaller volume requirement. Also no whooshing. I like it firing out of the back of the cabinet - felt, not seen.

Yes, I think this might end up heavy.
 

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