New gear and measurements

[MayInJune]

Hi, newbie here, need some advice plz.
I am looking for new equipment: streamer, dac, amplification, speaker. Got a few questions:
1. Which are the most important technical specifications published for audio gear, and
2. how would these measurements be audible in sq?
3 .Which specs are important to match between gear throughout an audio chain?
Thanks in advance. MiJ

[GregWormald]

This is a HUGE question! and is the subject of absolutely furious debates that have been ongoing for decades.?

All comments are IMO.

 

1. The most important spec is the price--it needs to be within your range.

2. Generally, although with numerous exceptions, the higher the price the better the sound.

3. Most regular gear these days is readily interconnectable.

 

Speakers, the room, and the set-up are the most individual and will make the most obvious differences in the overall sound.

 

Starting at the source, once anything in the music is lost it's lost forever and can't be regained further down the chain.

 

The ultimate choice remains with you--if you like it, it's good; if you don't, it's not; no matter what the specs say. Published specs may only be reliable if the tester and the test is competent and honest. Manufacturers' specs and statements are PR and are designed to sell the gear.

 

The most important thing is that you enjoy the music. Listen to as much as you can in your room and compare the enjoyment, not the bass, treble, etc. And have fun.?

 

 

[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

[MayInJune]

Thank you Mr. Wormald,
you generic answer to my questions were quite friendly, but not much help.
In general I am with you, and I really don't want to open a can of worms with my questions.
I just want to develop myself into an educated customer, who may understand,
when he is balderdash'ed by Audio store salesmen.
Asking/reading about/understanding specifications and their translation into real life values may help a lot with that.
MIJ.

[MayInJune]

1 hour ago, iaval said:

Hope that answers at least part of your question

@iaval
Thank you very much, that's a lot of valuable information in one answer.
Need time to understand all of that. May have some more question afterwards.
Thanks, MIJ
 

[audiobomber]

Looking for sound quality in the numbers is a hopeless cause. I first found this out decades ago, when a I heard a 40W amp that blew away a much more expensive 200W amp, and an amp with 0.5% THD that made amps with 0.005% distortion sound like toys. Even cheap DACs have impeccable specs these days. I don't ignore specifications, but they will tell you very little if anything about sound quality.

[Ryan Berry]

On 12/12/2018 at 3:23 PM, MayInJune said:

Hi, newbie here, need some advice plz.
I am looking for new equipment: streamer, dac, amplification, speaker. Got a few questions:
1. Which are the most important technical specifications published for audio gear, and
2. how would these measurements be audible in sq?
3 .Which specs are important to match between gear throughout an audio chain?
Thanks in advance. MiJ

 

 

We're talking about this in another thread in the General forum.  Charles Hansen used to say the most important measurements are weight and size, so you'd know if you could fit it on the shelf and if it would be able to hold the unit up!  But more seriously, it's really a complicated question that's a bit more involved than understanding what each is measuring (though it's a good start)!  Circuit designs, like feedback vs. no feedback, balanced vs. single-ended, linear vs. switching, and so on all play roles in how a unit sounds and can effect measurements.  As mentioned by audiobomber, it's pretty close to impossible to shop by the numbers.  It really takes spending some time trying out different gear and finding out what appeals most to you.  Not an easy hobby, but certainly rewarding when you do find that piece.

[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. 

[MayInJune]

7 hours ago, Ryan Berry said:

Charles Hansen used to say the most important measurements are weight and size,

LOL to Charles Hansen, R.I.P.
@audiobomber @iaval @Ryan Berry - Thank you for responding ? 
I do not live close to big cities, where I can easily shop equipment every day. Visiting showrooms is a an intricate task. Demoing at home is, unfortunately, not really an option. Too much products to chose from. I need to prepare my listening sessions prior to shopping with a level of expertise on the subject.
Maybe I am a cheapskate, but spending 5-10000 quids for a new system would contain a lot of hard work already done for me.
I won't do that without research, selection and mailing/calling shops about availability beforehand. If I assume, that most reviews are favorable to the industry, I need to focus on some comparable aspects/standards to make any preliminary selections viable. And in reverse, I need to check out, if the shops just offer "their" products or choose combinations with care. I am aware that selling/buying blindly by numbers is prone to create problems, but that has never been my intent. Nonetheless, I need to find a guideline for listening in the showrooms. In the end, it will be my ears that pull the trigger, but prior to that my brain may select options/combinations.
MIJ
 

[audiobomber]

Your question is too broad. Which components are you looking to buy? There are many ways to configure a system, especially these days with streaming.

 

The best way for you to end up with a great system is to tell the people here what you are trying to do, and ask for specific recommendations. Specs are not helpful in general. I am having a discussion on another board, where someone touted the Chromecast Audio DAC as having better specs than a Schiit Yggdrasil. That may be true, but I'd much rather listen to the Yiggy. ?

[Ryan Berry]

My pleasure.  The biggest issue that I have with measurements is that, barring perhaps a few outliers, most high end manufacturers today have generally good measurements.  You're not going to see many companies trying to pawn off something that has a SNR or cross-talk so bad that we could eliminate them from the running after a casual browsing of some spec sheets, so they really don't help all that much.  They also complete ignore design principles that really carry the bigger weight in how a product sounds.  For us, we know that a fully balanced design is better than single-ended.  We know that having no feedback sounds better than having feedback involved somewhere in the circuit.  We have almost every component made to custom specifications that don't exist on Digi-key or Mouser, but they aren't reflected in a spec sheet.  In fact, some elements like the zero-feedback can make some specs look worse on paper, but we know that the trade-off in sound quality is more than worth the extra design effort. 

 

This all makes the entire process a pain for you as a consumer to really properly shop around for audio gear and a pain for us as a designer to properly convey the features we have created, especially in a world full of buzz words already.  Perhaps one of the nicer parts about having the internet and forums around is that we can at least find those that want to learn more and talk to them directly instead of hoping they bother to call.  Thanks for asking the question, it makes a fun conversation!

[audiobomber]

On 12/16/2018 at 2:56 PM, Ryan Berry said:

We know that having no feedback sounds better than having feedback involved somewhere in the circuit. 

 

I'm not sure about that being a universal tenet. Most amps use negative feedback, and those that don't aren't necessarily better. 

 

According to Schiit, my Asgard 2 headphone amp/preamp has "no overall feedback in high gain mode, 12dB feedback in low gain mode". I prefer the sound in low gain mode due to (very) slightly smoother highs. Possibly lower THD due to feedback has an audible effect?  Or possibly the lower noise floor in high gain mode is an advantage, although I don't hear any noise.

[Ryan Berry]

2 hours ago, audiobomber said:

 

I'm not sure about that being a universal tenet. Most amps use negative feedback, and those that don't aren't necessarily better. 

 

According to Schiit, my Asgard 2 headphone amp/preamp has "no overall feedback in high gain mode, 12dB feedback in low gain mode". I prefer the sound in low gain mode due to (very) slightly smoother highs. Possibly lower THD due to feedback has an audible effect?  Or possibly the lower noise floor in high gain mode is an advantage, although I don't hear any noise.

 

You're right, there's a lot of factors that led up to this conclusion for Ayre, and it's true for our design, but may not be for others.  Charley's short answer on negative feedback was that if you do everything right beforehand, you don't need to introduce negative feedback to try and mask anything later.  There's actually a bit Charley wrote about it here: 

 

I know that there's controversy on the subject, especially with broad statements like that, but it's audio, so of course there's controversy.  We've actually used negative feedback in our design twice.  In both cases, we thought it was great at first and managed to release the product with it.  We ended up hating it so much after living with it for a couple months that we had to recall all the units and perform a free update to get the units back up to our standard.

[audiobomber]

I understand what you mean, but this thread was started by someone wanting a list of specs for buying an audio system. Most of the responses have suggested that specs are not a reliable indicator of sound quality. If he were to exclude every amp that uses negative feedback, choice would be very limited and not necessarily provide the best value.

[Ryan Berry]

I think the point was rather you can't use specifications to find a perfect audio product.  It takes listening to them to truly reach any informed conclusion.  Putting on most filters, like feedback or no, balanced or not, etc. is still shopping by specifications.