New gear and measurements

[iaval]

15 hours ago, MayInJune said:

Which are the most important technical specifications published for audio gear

THD+N, IMD, crosstalk, DR, S/N, crossover distortion, maximum load, output impedance, no-load voltage, load voltage, jitter, filtering, oversampling, frequency response to name a few

 

15 hours ago, MayInJune said:

how would these measurements be audible in sq?

THD+N (total harmonic distortion + noise) is basically how a pure sine wave is distorted from input to output, this distortion is visible of spectrum as additional harmonic content present along with the initial sine wave, and it's audible as roughness of individual tones, and manifest itself as harshness in percussion. Should be below 0.1%

IMD, or intermodulation distortion is usually non issue, but it's basically mixing two different signals together and higher values would yet again show as harshness, especially in treble region. Should be below 0.1%

Crosstalk is simply volume difference between channels. Lower values will mix channels together. It's impedance-dependent. Should be at least 50dB

Dynamic range is the difference between loudest and quietest signal. At least 100dB for 24bit gear, 90dB as minimum.

Signal to noise ratio, pretty much the same as DR, only towards noise. At least 100dB for 24bit gear, 90dB as minimum.

Maximum load - minimum impedance allowed for amplifier. Should be 8 Ohm for HP amps and below 2 Ohm for speaker amps.

Output impedance - resistance added by the amp towards transducer, should be as low as possible (minimum 1/8 of the impedance of the transducer). Below 2 Ohm for HP amps, below 1 Ohm for speakers. 

No-load voltage - peak voltage delivered by amp into infinite load. Useful for comparing low output impedance amps among each other.

Load voltage - as above, however into known loads (250Ohm, 600Ohm, ...). With this, you can calculate maximum volume for your own set of HP/speakers.

Jitter - highly dependent on the topology and nature of the signal

Oversampling - how many times is the original sample rate raised to prevent ringing and aliasing errors - usually 128x or 256x

Frequency response - which frequencies pass through the said device, at least all audible frequencies 20-20000Hz should be there, with maximum of 0.5dB difference in the baseband

Filtering specifies parameters of the low-pass filter to prevent unwanted frequencies entering your signal chain. Mild ones include 24kHz LPF with 6dB/oct roll-off, sharper filters might introduce ringing. LPF is optional. 

 

Hope that answers at least part of your question

[iaval]

4 hours ago, Ryan Berry said:

most important measurements are weight and size

and power consumption ☺️

 

The issue is not that manufacturers provide incorrect specs, but that their specs is often incomplete. 

 

Let's demonstrate it on my recent item of interest - Shanling M0:

 

DAC	ESS ES9218P
Output power	80mW @ 32Ω
Recommended headphone impedance	8 - 300Ω
Frequency response	20Hz - 20kHz (-0.5dB)
Distortion	0.004% (500mV)
SNR	118dB
Output impedance	0.16Ω
Channels resolution	70dB
Dynamic range	> 105dB
	Up to 32bit 384kHz / DSD128

 

DAC - Okay, but other than to show off, that in itself won't guarantee anything. Even quality DAC will perform poorly in bad PCB layout

Output power - listing just 80mW @ 32Ohm is not enough to have an idea how loud it's going to be with any headphone other than 32Ohm. Also missing under what THD+N was that 80mW achieved

Recommended headphone impedance - useless (all headphones have different sensitivity, just by impedance it's impossible to draw conclusions)

Distortion - we don't know the load and frequency response, good thing they at least mentioned the voltage

SNR - 118dB - fine but again bandwidth would be helpful

Output impedance - great, finally value we can use

Channels resolution - bad translation? Might be crosstalk, in that case, very good.

Dynamic range - again, missing bandwidth

 

An example of "good enough" specification sheet would be Fiio X5II:

http://www.fiio.net/en/products/41/parameters

For that, Fiio gets a thumbs up. They even list the testing conditions.