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Alpine UTE-73BT Review (Head Unit)

amirm

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This is a review and detailed measurements of the Alpine UTE-73BT Digital Media Receiver. It was kindly purchased new by a member and drop shipped to me. It costs US $99.99 on Amazon including free shipping.

Can't say that the UTE-73BT looks any different than a thousand other head units:

Alpine UTE-73BT Review Head Unit.jpg


What was remarkable was how light this unit is. I don't think I have ever held a head unit that weight this little. Taking out the CD mechanism helps of course but still, it feels like it is made out of plastic even though it is not.

An Aux analog input is provided in the front as well as the USB input (I left the door open). I used both for my testing. Alas, the unit could only read one of my test files on the flash drive. It would refuse to read any other. The files were all uncompressed FLAC which it seemed to recognize but wouldn't read. Strange.

Back panel shows pre-outs which I used for testing:

Alpine UTE-73BT Review Head Unit Bluetooth.jpg


Standard multi connector is used for power and speaker outs.

To test the unit, I had to power it with my bench power supply. This causes a problem in testing because we now have AC ripple that does not exist with a battery as a source. I tried to work around it as you see below but I am not happy about it. The standard solution is to power it using a battery but I can't bring one indoor. Have to see if we will be testing a lot more auto audio and if so, I will invest in proper way to power them.

Alpine UTE-73BT DAC Measurements
Per above, I put my standard 1 kHz test tone on the flash drive and had the unit play it while I measured the performance out of pre-out. I adjusted the volume one notch to get the output to be 2 volts:

Alpine UTE-73BT Measurements DAC.png


This is obviously not good performance. Noise floor is quite high by desktop standards as are distortion components. You are getting about 10.5 bits of performance which is dismal for a home system. I have not tested a lot of head units to give this a precise rating. I did test a Sony RSX-G9 which scored far better with a SINAD of 89 so much better job can be done in this form factor.

Analog Input Measurement
I fed the unit analog signal through Aux input. I started with 2 volt input but that severely clipped it so I backed that down to get a dashboard view:

Alpine UTE-73BT Measurements Aux In.png


So no hope of improving performance by using an external DAC. Sweeping the input shows the clipping behavior:
Alpine UTE-73BT THD vs Level Measurements Aux In.png


Running a frequency response sweep shows that the input is digitized at 44.1 kHz:

Alpine UTE-73BT Frequency Response Measurements Aux In.png


There are parametric EQs in this unit so likely it digitizes the input to allow for that even for analog input. They could have done a better job though by keeping frequency response more flat.

Signal to noise ratio shows that we are missing dynamic range of 16 bit CD:

Alpine UTE-73BT SNR Measurements Aux In.png


Crosstalk is fine:

Alpine UTE-73BT Crosstalk Measurements Aux In.png


Power Amplifier Measurements
I used the Aux in to test the power amplifier left and right channels:

Alpine UTE-73BT Measurements Power Amp Aux In.png


Now you see the problem I talked about at the outset. We have a 60 Hz mains peak that dominates the measurements. This is actually the better of two bench power supplies I have. To reduce the impact of this noise, I activated a-weighting filtering in the analyzer and got this:

Alpine UTE-73BT Measurements Power Amp a-weighted Aux In.png


So we are back to 74 dB SINAD.

Frequency response is dominated by the Aux In's own bandwidth:

Alpine UTE-73BT Frequency Response Measurements Power Amp Aux In.png


Signal to noise ratio is much worse now due to power supply noise but even using a-weighting, we are still coming up short:

Alpine UTE-73BT SNR Measurements Power Amp Aux In.png



I was surprised to see the heavy rise in distortion as frequencies got lower:

Alpine UTE-73BT THD+N vs Frequency Measurements Aux In.png


This is usually due to lack of capacitance storage in the power supply.

At 4 ohm, this thing puts out the old standard 5 watts of power:

Alpine UTE-73BT Power 4 ohm Measurements Power Amp Aux In.png


Very sad. Switching to 8 ohm surprisingly gets you more power:

Alpine UTE-73BT Power 8 ohm Measurements Power Amp Aux In.png


Back to 4 ohm, if you allow distortion go up higher, you do get about 10 watts:
Alpine UTE-73BT Peak and Max Power 4 ohm Measurements Power Amp Aux In.png


Conclusions
Hard to have high expectations when paying just $100 for a head unit. Putting that aside, there is nothing here to get excited about. Performance is limited in multiple ways to around 74 dB which is quite disappointing by desktop standards. But maybe most of them are this bad, I don't know yet.

I don't have a recommendation for you either way. Need to get more data to have a good reference. Personally though I have no use for a head unit with just 5 watt of power. That is a recipe for poor performance by itself. Either get an external amp or one of the few 25 watt/channel units.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

digicidal

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Have to wonder if/how much better it would measure if it were a pure pre-amp configuration. It's not like those 5W are gonna be adequate for all but the quietest car interiors... and getting there either requires a very expensive car... or several times the cost of the head unit in damping/insulation (as well as all the hours tearing everything apart and putting it back together). Seems like another "solution in search of a problem" product to me.

Although to be fair even 15bits of DR in an automotive environment is plenty... at least when in motion. Just 5W however, is not plenty in any setting IMO.
 

3125b

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They claim 4x 18W. Not a very impressive spec, yet still it fails completely :)
Makes me wonder about my even cheaper Pioneer. It gets pretty loud, so probably more than 5W/Ch.

The signal quality I think is ok for what it is. Between the high noise floor and a million other things to concentrate on, a car is just not a place for critical listening, so fidelity doesn't really matter beyond the "not completely broken" point.
 
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Frank Dernie

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Performance is limited in multiple ways to around 74 dB which is quite disappointing by desktop standards.
IME only music with low dynamic range "works" in a car anyway. Anything with dynamics or, particularly, a big difference between quiet and loud bits needs gain riding IME and I gave up listening to the sort of music I like best in my car decades ago, the background is so loud it is pointless.
If I listen to hard rock, which i also like, it tends to encourage me to drive too fast...
I have a soft top sports car and with that I only switch on the sound system in a traffic jam - it is inaudible over about 30mph!
 

milosz

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No tests of the tuner section? Seems like a complete test of this unit would also measure it's tuners.

FYI you can get a very nice 12 volt gel cell - like a motorcycle battery - for very little money. It would power this unit for hours. Seems to me if you are going to test auto stereos it might be worth spending the $25 on a 9 AH battery => https://www.amazon.com/dp/B00K8V2Y8W/ref=cm_sw_em_r_mt_dp_1ZZXJHCKCEGAD2QW77SM
 

Robbo99999

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I was gonna say, this is normally used in a car right? It's 'just' one of those common fronts you see as the main stereo unit in a car?
 

BeerBear

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The files were all uncompressed FLAC which it seemed to recognize but wouldn't read. Strange.
Uncompressed FLAC is a rather obscure format, that you typically have to jump through hoops to produce, so I'm not very surprised. (Assuming you meant that literally.)
 

Francis Vaughan

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Just eyeballing the spectra it looks suspiciously as if the entire mess is dominated by intermodulation distortion produced from the residual AC on the power supply. This device is just not intended for anything other than a pure battery to power it. Which for $100 isn't unreasonable. It would not surprise me to see the performance improve significantly when fed clean power.
 

rodrigaj

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I had never heard of the term "head unit" before.
So this is a unit intended for an automobile.
Why is ASR testing automobile stereo systems?

(of course, you're welcome to test whatever you like - I'm just wondering.)
 

pjug

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The power into 4 ohms is really strange. Any chance the bench supply was limiting? It needs to put out 6A 3A peak to get to the 18W into 4-ohms spec, right?

edit: brain cramping, which makes me think this not likely the problem
 
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ck42

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Oh wow..... @amirm , I think you might've opened a pandora's box on this one. Never saw a headunit review coming!!
You could double/tripple your testing load by including car audio equipment...and you'd bring in a WHOLE new audience for those reviews. You up for that? :D
 

franspambot

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Oh wow..... @amirm , I think you might've opened a pandora's box on this one. Never saw a headunit review coming!!
You could double/tripple your testing load by including car audio equipment...and you'd bring in a WHOLE new audience for those reviews. You up for that? :D

Agree. I am always thrilled to see one of these types of reviews pop up.

Once we sort out our new car situation and I look at upgrading its components, I'll be sure to send something your way!
 

m8o

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What's the noise floor of everyone's car from wind, tires, engine exhaust, other vehicles, etc.? Mine is pretty high. I doubt I'd ever be affected by this thing's dismal noise floor.

P.s. while sure, ya, the ps is normally a battery and ya, the performance seen here is skewed using a bench ps ... but dont think Amir using a battery will let this perform way better. Dont forget about the alternator noise, which could be significant. Add that in to the test environment mix. If this is tested with a power source from the actual environment it is designed to operate in, I would expect worse not better performance.
 
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sssn

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Wow, has some else ever done technical measurements on car radios? :D Anyway, it's much better than I expected.
 

Tom C

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I’m no expert but...
The only time the unit will be powered by the battery only is when the car is parked, and the motor’s off, right? Otherwise, the alternator will be running and charging the battery. Is the alternator output ripple free? Or does the battery supply smoothing, like a capacitor?
 
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