[tmart]

So I’m new to this forum. I’m a computer engineer and I love looking at the built in amplifier ICs in mobile phones. I came across a teardown of the new Motorola X and saw it has a NXP TFA9890 High Efficiency Class-D Audio Amplifier with “adaptive sound” and Qualcomm WCD9310 Audio Codec. “It can deliver 7.2 W peak output power into an 8 Ω speaker at a supply voltage of 3.6 V. The internal boost converter raises the supply voltage to 9.5 V, providing ample headroom for major improvements in sound quality.” This is the first mobile phone amp with a DC-to-DC boosted 9.5V supply voltage.
I was just wondering what people thought of the Motorola X's built in amplifier compared to the iPhone 5 (Cirrus CS35L19 class-D audio amplifier with Apple 338S1077 Cirrus audio codec), Galaxy IV, or HTC one/x because I was planning on buying one of these phones to use as a source without DAC. Thanks guys!

 

[bcarr112281]

 The internal boost converter raises the supply voltage to 9.5 V, providing ample headroom for major improvements in sound quality.” This is the first mobile phone amp with a DC-to-DC boosted 9.5V supply voltage.

Hi, tmart -

Thanks, and welcome to Head-Fi!

I'm not surprised to hear about the boost converter. I'm not an engineer, but I suspect the converter enables the X's rear speaker to output sound at a higher volume than average. Indeed, I'd read that the phone monitors the speaker membrane's movement and temperature, apparently allowing major boosts in volume without risking damage to the speaker itself. It's certainly a nice concept.

These specs wouldn't seem to indicate a great deal about the quality of the audio the phone produces, especially via headphones. Many of the folks on this board will tell you that phones simply can't compete with dedicated high-quality DACs and amplifiers, and I'm skeptical that the Moto X would prove the exception.

I'm in the market for a new phone, and the Moto X is on my list, so perhaps I'll get to try it soon. Still, capacity is limited to a maximum 32 GBs with no external storage. I doubt there are many audio enthusiasts--myself included--who'd want to consider it as a music player.

Regards,
Brian

 

[tmart]

These specs wouldn't seem to indicate a great deal about the quality of the audio the phone produces, especially via headphones.

Just curious, how would this not correlate to higher quality for headphones? I thought that having a DAC took the uncompressed audio from the device to be amplified elsewhere.

 

[Baroninkjet]

I have not seen anything on its audio quality in print yet, though historically Motorola does not have the reputation of making it a priority. I saw one in AT&T the other day. Very nice presentation, though I think my next one will be LG G2.

 

[bcarr112281]

Here's an excerpt about the Moto X's audio quality from AnandTech's full review:

Lately I've been getting more and more jaded about line out quality on devices. There's something about close proximity to a transmitter and the confined spaces in a smartphone that makes getting good clean audio a challenge for everyone. That said I was impressed by the sound quality on the Moto X both on line out, on calls, and on the speakerphone. . . . I listened to a lot of music while traveling on the Moto X using my Shure SE535 IEMs and came away pretty impressed. I've heard a lot of smartphones that either lacked a lot in the mids, had discernable noise, or various issues driving IEMs at low volume, but I didn't encounter anything negative on the Moto X.

And then,

On phone calls, I was actually shocked by how good the Moto X sounded. I had no problems hearing people on the other end, and found myself wanting the Moto X when I wasn't using it. . . . I am still surprised by the fact that I'm drawn to the Moto X because of how much different in a positive way it sounds from some of the other handsets I've played with recently, especially when on conference calls. I heard positive feedback from the terminating side of the call as well, that I sounded good on both speakerphone and handset mode.

It seems to me that the Moto X is designed to work well as a phone, yet its audio playback also appears to compare highly against other devices in its category. Still, I suspect there are better options, especially among dedicated audio players. I don't think fancy amp specifications alone are indicative of playback quality.

Of course, these impressions don't suffice; an honest evaluation would require proper testing of the Moto X's audio performance.

Thanks,
Brian

 

[Gilly87]

I'm very interested in the Moto X and am curious if anyone can compare it to the Nexus 4, preferably someone who has heard the N4 with Franco Kernel. Very curious as I'm tired of the N4's shape and want something smaller.

 

[Baroninkjet]

See the freq. response graph.
 
http://www.gsmarena.com/motorola_moto_x-review-971p6.php

 

[Gilly87]

Ugh. Such a shame. Its got a great screen and is the perfect size...too bad.
 
Quote:

  See the freq. response graph.
 
http://www.gsmarena.com/motorola_moto_x-review-971p6.php

 

[Gilly87]

Thanks for saving me the $600, by the way. Head-Fi helped my wallet? What?!?!

 

[C19932]

Pardon my retardness, I don't know who to 4ad frequency graphs. But what's bad about the moto x audio quality?

 

[Gilly87]

No worries The numbers at the bottom represent hertz, the measure of wavelength of sound waves. Lower hz means lower frequency, means deeper notes. In this case, the moto x suffers from loss in the frequencies below 100 hz, which means bass will be under-emphasizedand and probably not very well textured, which is unfortunate because the rest of the frequency response is rather flat and even, and apparently the amplifier is quite good. The screen is also rather good and the phone feels very nice in the hand despite its large screen. A real shame.

Pardon my retardness, I don't know who to 4ad frequency graphs. But what's bad about the moto x audio quality?

 

[gabbadabbadoo]

You know, I never expected anything from my phone and had no intention of using it as an audio device, but the HTC One is really not that bad.
 
I find myself using it randomly in the car or in the kitchen when I don't want to pump my home system.
 
Has anyone else had this same phenomenon? It doesn't always work well when using as a source out, but decent with headphones.

 

[Gilly87]

Just got my hands on the Nexus 5 and it's not half bad either, listening to Fever Ray through the N5 -> SM2 V2s as I type.

 

[C19932]

No worries The numbers at the bottom represent hertz, the measure of wavelength of sound waves. Lower hz means lower frequency, means deeper notes. In this case, the moto x suffers from loss in the frequencies below 100 hz, which means bass will be under-emphasizedand and probably not very well textured, which is unfortunate because the rest of the frequency response is rather flat and even, and apparently the amplifier is quite good. The screen is also rather good and the phone feels very nice in the hand despite its large screen. A real shame.

Thanks for the reply! I am using the HTC one s right now and the bass is wonderful with my Sennheiser ie8. I compared my HTC One S to the htc one and I found the bass in the HTC one to be not as deep as the one s. But the frequency graphs for both phones on gsmarena seems like the same.... Are there any other factors that affect bass output? Both phones are running aosp 4.3

 

[Gilly87]

Do you have any settings like Beats Audio, DSP manager, equalizers, tuners, etc. disabled on both? Graphs aren't everything, but they shouldn't sound too terribly different. Also different music player software could potentially have a built-in digital EQ, so be sure you're using the same music app (Neutron is a good music player app to use as a reference, more features than the stock one too, although the interface isnt the best); even the built-in music players could be different since we're talking different versions of android, different firmware, etc.
 
The One S was a great phone; when it gets old and glitchy try rooting it and flashing a custom ROM (if you're up to the challenge), it can give new life to an old buggy phone if you're looking to keep it alive 
 
EDIT: I'm looking at the graphs side by side, and while they do look VERY similar, the One does roll off just a tad more quickly in the lowest of lows. The One S also has slightly less dynamic range, meaning that it pushes the whole sound forward, which could cause a bigger emphasis in bass in some cases. The differences are small, though, from a purely technical standpoint; you have very good ears, my friend!
 
Quote:

Thanks for the reply! I am using the HTC one s right now and the bass is wonderful with my Sennheiser ie8. I compared my HTC One S to the htc one and I found the bass in the HTC one to be not as deep as the one s. But the frequency graphs for both phones on gsmarena seems like the same.... Are there any other factors that affect bass output? Both phones are running aosp 4.3