Alpine UTE-73BT Review (Head Unit)

[GWolfman]

@amirm Congrats on breaking into new ground (car audio equipment)!

(At least the first IIRC.)

 

[Matias]

ASR already measured car audio amps before, it is not the first time venturing into car audio. It is the first head unit though.
https://www.audiosciencereview.com/...undigital-sd-600-1d-nano-car-amplifier.11521/

Although I always wondered if the Alpine amps are as good measuring as they claim.
https://www.audiosciencereview.com/...d-600-1d-nano-car-amplifier.11521/post-330869

 

[SMc]

I have a similar Alpine head unit installed in a noisy 30-year-old car. From my experience, yes, the internal amp is inadequate to overcome road noise. Adding an Alpine power amp helps that but is susceptible to alternator noise when using the high level connections. Sound quality depends on eq to overcome the car interior's contribution.

Actually using the unit is a juggling act of convenience vs sound quality. Accessing the PEQ requires an app running on a phone. For a long time, I just used the phone's Spotify eq for analog but couldn't tell if it worked over the more convenient Bluetooth or digital connections.

Best results come from running the app PEQ over the wired digital connection and using the preamp outputs to the power amp. Even under pandemic shelter-in-place conditions, I haven't been curious enough to suss out all the combinations of source vs app sound quality. I am reasonably pleased with the results for the money.

I'm happy to see the measurements. This may be all you need if you only listen casually in a parked car with the engine off.

 

[Objectivist01]

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:

View attachment 129259

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:

View attachment 129263

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:

View attachment 129267

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:

View attachment 129268

So no hope of improving performance by using an external DAC. Sweeping the input shows the clipping behavior:
View attachment 129269

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

View attachment 129270

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:

View attachment 129271

Crosstalk is fine:

View attachment 129276

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

View attachment 129272

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:

View attachment 129273

So we are back to 74 dB SINAD.

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

View attachment 129274

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

View attachment 129275


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

View attachment 129277

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:

View attachment 129278

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

View attachment 129279

Back to 4 ohm, if you allow distortion go up higher, you do get about 10 watts:
View attachment 129280

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/

Amir, is the SNR weakness so much noticeable considering car itself is a noisy environment where the engine noise itself would kill the benefit of a high snr unit? Also I found some figures after smeasurments for jvc kebwood units quite good in some German websites. I am curious to see them on your bench some day.

 

[Sky Way]

As always, great review. For me ASR is the only trustable source over the web concerning audio equipment testing.
Thanks Amir.

Keep up the good job.

 

[michaelahess]

I've got the old version of this, the UTE-62BT in my '06 Dodge RAM MegaCab. No amps, just the HU. It gets LOUD. I've EQ'd the heck out of it to sound good with the engine running, turning up as I speed up generally keeps the sound the same. It never struggles. The app makes it super easy to EQ and setup delay's though.

I have a Morel speaker setup with a 5 channel Alpine amp and DSP in my BRZ, and yeah, it has a better sound than the "cheapo" JBL GTO's in my truck, but they both do very well for their applications. I have over 100lb of sound deadening material in the BRZ though. Talk about a high noise floor...

The 62BT weights 8oz more than the 73BT so I'm wondering if it actually has a better build, still Class D amp, but that's a significant difference in a 1-2lb device.

Testing car audio is a fantastic idea, as it's even more "oversold" than home HiFi. I used to do SPL comps like 25 years ago, with the occasional SQ comp, and NOBODY knew what they were doing, or what sounded good or "right." Science FTW!

Edit: Oh, and yes you have to test at 14v, alternator output NOT battery output. I used to use 1 farad caps to overcome the poor alternators in old cars. Modern ones have better ones it seems, have to I guess to power all the new tech!

 

[Sky Way]

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

This makes me wonder if: adding a capacitor at the power input when using in car will improve performance??.

If so, witch capacitor value will be adequate?

 

[michaelahess]

This makes me wonder if: adding a capacitor at the power input when using in car will improve performance??.

If so, witch capacitor value will be adequate?

Hence why I used a cap in the vehicles. Sub bass will drop the voltage a LOT, the cap smooths it out. Doesn't help for anything but subs though. At least not with well designed amps that don't weigh 14oz...

 

[Frank Dernie]

Car is short for Carrier

News to me!

 

[dmac6419]

News to me!

one that carries

 

[Xyrium]

Man... this harkens me back to the 80's. I love it. Clarion, Nakamichi, Kenwood, Rockford Fosgate... etc. Good times.

 

[amirm]

What was the input voltage? Car audio equipment will suffer at 12volts vs the 14.4 volts when the alternator/charging system is running

13.7 volt.

 

[amirm]

@amirm Congrats on breaking into new ground (car audio equipment)!

(At least the first IIRC.)

This is actually the fourth or fifth head unit I have tested. I have also tested some car amps.

 

[stevenswall]

Very revealing of manufacturer specs being misleading. Glad we have a warning for purchasing head units now, hopefully it's not like home theater receivers that all have measurable issues and discrepancies between the specs and real world performance.

On the other hand, is it possible to get good sound in a car? I always thought the alternating reflective and absorbent acoustics would cause a problem, and most speakers are pointed into seats and windows instead of at the ear. Maybe a system with small mid-ranges and tweeters that could point at the users ear and all the larger speakers low passed. Might require some very large side pillars though.

 

[amirm]

This makes me wonder if: adding a capacitor at the power input when using in car will improve performance??.

If so, witch capacitor value will be adequate?

People use all manner of caps going as far as one Farad or more!!! They also use secondary batteries and such.

 

[Doodski]

The standard solution is to power it using a battery but I can't bring one indoor.

Good decision. I worked with DC battery power for many years and we had clothing corroded with holes in it, acid spills on floors, gassing odours and even explosions. Using lead acid batteries indoors is a bad idea. Ultimately I bought the biggest baddest HP rack mount variable DC power supply that I could find, fit on the workbench, afford and went that route.

 

[Deleted member 31750]

haven‘t seen one of these for ages. Reminds me my childhood. The cool one was the removable ones that you could take home with you

 

[Tks]

This is actually the fourth or fifth head unit I have tested. I have also tested some car amps.

Quick question, do you have any idea how car speaker systems are validated or tested for? Is there any industry standard for this sort of thing?

 

[Frank Dernie]

one that carries

Not in any English dictionary I have seen though.
https://www.etymonline.com/word/car

OTOH there is a big difference between English and the similar language used in the US IME.
The first time I noticed it was in a restaurant where a waitress said "I'll be with you momentarily" which made me think she was so busy she couldn't spare long to take my order, because "momentarily" means "for a short time" in english but I discovered it meant "in a short time" in the US.
I learned a lot more differences over the next 50 years of visiting it has been quite fun!

 

[hardisj]

Quick question, do you have any idea how car speaker systems are validated or tested for? Is there any industry standard for this sort of thing?

There is a CEA standard for amplifiers and some companies use it and slap the label on there. But, by and large, there is no standardized testing. That is precisely what got me involved in testing speakers over a decade ago. That was what I started out with using Klippel products.