DAC types and their sonic signature

[andreasmaaan]

My father in law had a BOSE sound wave cd player for over 10 years and loved it.
It developed a fault and, with it being out of warranty, decided to take it apart to see if he could fix it (he's like that).
Anyway, he was shocked at what he saw inside.
Basically a small PCB with speaker wire going to the two tiny 2.5 inch drivers with an elaborate series of slats which directed the soundwaves (for want of a better word) which gave the illusion of good sound.

I guess it looked something like this?

I don’t have any published tech info on this design, but what that looks like to me is a long port or transmission line. In other words, it is the kind of thing you see on most standmount speakers, folded upon itself to maximise space inside the small enclosure. This is no more a “trick” than in any other design in which it’s used. It has the effect of allowing the small drivers to produce more bass than they would in a sealed enclosure of the same volume, with less cone excursion (assuming they are high-pass filtered at a suitable frequency to prevent over excursion, which no doubt they are). It makes sense in an enclosure of such a small volume.

Now, I’m certainly not saying this justifies the many 100s of $$$ the unit no doubt costs My personal experience of Bose products is that they tend not to perform as well as some similar units in their respective price ranges. But I wouldn’t call this a “trick”; it’s just a smart way to get a small speaker to produce an adequate amount of bass.

 

[Snarfie]

I also decided to buy a dac because of a promising test Amirm did on the Topping D10. The difference between my older dac that i used from my Xone 4D an the Topping D10 was not hugh. The biggest difference (atleast 50% improvement of total sound impression) i noticed when i used Roomcorrection software. To compare that with the signature between 2 quality dac's is imo more or less neglecteble.

 

[Sparky]

I guess it looked something like this?

View attachment 28910

I don’t have any published tech info on this design, but what that looks like to me is a long port or transmission line. In other words, it is the kind of thing you see on most standpoint speakers, folded upon itself to maximise space inside the small enclosure. This is no more a “trick” than in any other design in which it’s used. It has the effect of allowing the small drivers to produce more bass than they would in a sealed enclosure of the same volume, with less cone excursion (assuming they are high-pass filtered at a suitable frequency to prevent over excursion, which no doubt they are). It makes sense in an enclosure of such a small volume.

Now, I’m certainly not saying this justifies the many 100s of $$$ the unit no doubt costs My personal experience of Bose products is that they tend not to perform as well as some similar units in their respective price ranges. But I wouldn’t call this a “trick”; it’s just a smart way to get a small speaker to produce an adequate amount of bass.

Yes! Exactly that!

You see, this is where my inexperience in these matters requires somebody like you to come in and guide me.
I'm open to constructive criticism and certainly not ashamed of being corrected.
You are if course correct and I suppose my use of the word "trickery" maybe wasn't the best choice of words.

I'm glad you agree on their price point though (at least I got something right) .
To go back to my father in law, once he realised he couldn't fix the BOSE, he was all set to buy another.
I stepped in and casually suggested he buy a small integrated amp with a tuner built in and a pair of bookshelf speakers instead.
He did and never looked back.
Not only did he get much much better sound quality and control but saved himself a fair few quid at the same time.

It's literally just clever marketing and smart looking products.

I stand corrected anyway sir.

 

[andreasmaaan]

It's literally just clever marketing and smart looking products.

I stand corrected anyway sir.

No sweat. Anyway, I also find it interesting to see what’s going on in these small speakers, which require interesting engineering choices to produce bass.

I agree with the “just clever marketing and smart looking products” statement in general when it comes to Bose today, although it has to be acknowledged that in the past Bose did interesting research and came up with some fascinating designs, many of which are mentioned in that article you linked earlier. These days, my impression is that they are mostly banking off their brand

 

[solderdude]

I don't like Bose products in general.
I do have to admit that their small active speakers do not sound bad and that the likes of QC35 are pretty good headphones.

 

[andreasmaaan]

And it must be acknowledged that Amar Bose invented noise-cancelling headphones.

 

[Sparky]

And it must be acknowledged that Amar Bose invented noise-cancelling headphones.

Very true indeed.

And a fine job they did too. All others followed in their wake.

 

[Dialectic]

I guess it looked something like this?

View attachment 28910

I don’t have any published tech info on this design, but what that looks like to me is a long port or transmission line. In other words, it is the kind of thing you see on most standmount speakers, folded upon itself to maximise space inside the small enclosure. This is no more a “trick” than in any other design in which it’s used. It has the effect of allowing the small drivers to produce more bass than they would in a sealed enclosure of the same volume, with less cone excursion (assuming they are high-pass filtered at a suitable frequency to prevent over excursion, which no doubt they are). It makes sense in an enclosure of such a small volume.

Now, I’m certainly not saying this justifies the many 100s of $$$ the unit no doubt costs My personal experience of Bose products is that they tend not to perform as well as some similar units in their respective price ranges. But I wouldn’t call this a “trick”; it’s just a smart way to get a small speaker to produce an adequate amount of bass.

Yes, it's a transmission line, and yes, Bose--somewhat incomprehensibly in light of the "prior art", as patent lawyers call it--was able to get a U.S. patent on nonlinear acoustic transmission lines.

I got a pair of Bose noise-cancelling headphones for free, and they are good for mitigating the drone of a commercial jet cabin. To this layman, noise cancelling seems to be the only area in which Bose has ever made contributions to the science of audio.

Now for my Bose rant:

Amar Bose was a smart man with terrible ideas about audio. His "ingenious" Bose 901 speakers are predicated on the ridiculous idea that, in lieu producing sound with a flat frequency response or even power response, a loudspeaker should mimic a particular acoustic--that of Boston's wonderful Symphony Hall--in crude fashion. The 901s are the second worst purportedly high-end speakers I have ever heard. (The worst are some Voxativ single-driver speakers that I heard in Singapore, which were so bad that I experienced physical pain while listening to them.)

When I briefly worked in CE sales some years back, I sold a ridiculous number of Bose cubes and Bose 1-2-3 systems to people (mostly upper middle class, college-educated folk) who couldn't comprehend, despite my best efforts, that Bose's in-store audio demos are cleverly rigged. I think it must be said that the Bose Wave Radio, the Bose cube (Acoustimass) systems, and Bose 1-2-3 systems all sound hideous, with boomy one-note mid-bass, no highs, and no (real) lows--just Bose.

 

[tential]

Yes, it's a transmission line, and yes, Bose--somewhat incomprehensibly in light of the "prior art", as they call it in patent law--was able to get a U.S. patent on nonlinear acoustic transmission lines.

I got a pair of Bose noise-cancelling headphones for free, and they are good for that purpose. To this layman, noise cancelling seems to be the only area in which Bose has ever made contributions to the science of audio.

Now for my Bose rant:

Amar Bose was a smart man with terrible ideas about audio. His "ingenious" Bose 901 speakers are predicated on the ridiculous idea that, in lieu producing sound with a flat frequency response or even power response, a loudspeaker should mimic a particular acoustic--that of Boston's wonderful Symphony Hall--in crude fashion. The 901s are the second worst purportedly high-end speakers I have ever heard. (The worst are some Voxativ single-driver speakers that I heard in Singapore, which were so bad that I experienced physical pain while listening to them.)

When I briefly worked in CE sales some years back, I sold a ridiculous number of Bose cubes and Bose 1-2-3 systems to people (mostly upper middle class, college-educated folk) who couldn't comprehend, despite my best efforts, that Bose's in-store audio demos are cleverly rigged. I think it must be said that the Bose Wave Radio, the Bose cube (Acoustimass) systems, and Bose 1-2-3 systems all sound hideous, with boomy one-note mid-bass, no highs, and no (real) lows--just Bose.

Wasn't until avsforum that I learned that all of these brands are a joke.
Now that I understand just how much performance you get building yourself, I haven't bought any home theater gear. Waiting until I can move into a larger place for some truly large drivers. A 15" sub was a fun introductory that was a game changer.

So while I wait, headphones!

 

[JohnYang1997]

The AEON flow closed is quite sensitive ... 112dB/V.
The AEON flow open is even 114dB/V
The impedance is a bit on the low side (13 Ohm), depending on the output stage of a phone (when it has output capacitors) there could be an audible roll-off in the lows.

Driven from a phone (1V out) he should be able to reach 85-90dB average.

HERE is a nice list with the efficiency ratings and impedances of many popular headphones. (Only the dB/V values are important, not the dB/mW)

dB/mW is very important. Or equivalent current requirements. dB/V tells you how loud it is, yes. But if the source is not capable enough it can get very distorted when impedance is low. 13ohm is alarmingly low especially for a planar. Low impedance tends to have higher db/V rating but in fact these are not efficient at all. And these are on the at almost worst end of a kind of a load for headphone amplifiers. Only 2-4 ohm iem or 8 ohm headphones can be worse. Iem being the worst fo them all.

 

[solderdude]

dB/V nor dB/mW say anything about the impedance of the headphone nor does it say anything about the abilities of the device(s) it will be connected to.

 

[Calexico]

While reading here on most of the forums i see that scientists prefer to spend time to intimidate people that hear differences instead of making more serious measurements.
The most used argument is that we are all audiophiles fooled by what we read on internet.

It would be a better idea that asr would spend time to find new measurements to improve scientific knowledge.

Instead of that asr relies on old measurements that have been elaborated mostly for marketting.

It's not complicate to have idea for new tests:
With no band limited measurements
- thd vs freq at different levels
- same with different samplerates and bitdepths
- finding ways to measure dsd
- testing the noise produce by the PSU of the dac and by the usb cable up to ultrasonic frequencies
- testing how the filter of the dac deal with the nyquist image and finding at wich frequencies it's located
- trying to find tests with complex signal to see if there are differences between dacs

Instead of trying to improve scientific tests asr try to fight against people that need more proof and asr call them audiophiles.

And asr is just arguing that these tests have no need.
How do they now that these tests are not needing without doing them?
Also how do they know if a dac has a failure in design without doing them?
It's not scientific at all.
It seems they are fooled by the marketing of classic tests that don't show all that can be showed.

Tests done show only the better aspects of the dacs.
To be revealing they should show worst aspects of the dacs.

For this reasons i don't trust much on asr.

Their measurements show only one aspect of dacs where all dacs perform about the same.
That's why asr believe they all sound the same.
That's just misinformation.

Those days people should be careful on what they read. Lot of things are made for money not for what they should be.

 

[JohnYang1997]

dB/V nor dB/mW say anything about the impedance of the headphone nor does it say anything about the abilities of the device(s) it will be connected to.

If you give me both dB/V and db/mW I can calculate the impedance of the headphone. And the current requirements for each level. And then comparing to the device output current capacity to see if the device is capable.

 

[JJB70]

I think Bose get a bad rap in some ways. I am not advocating their products but they read the way the market would go with respect to wireless active speakers and user (and fashion) friendly audio very early on and have been very successful serving their identified target markets. Weirdly I find those I know who buy Bose products are invariably very happy with them and keep them for a long time and aren't constantly fiddling and buying new gear like many who have a much greater knowledge of audio. And they do have a good research heritage.
The Bose products I do rate highly are their noise cancelling headphones, their noise cancelling know how is superb and if people want NC headphones then I would just point them to Bose or the top Sony NC models.

 

[dweekie]

If you give me both dB/V and db/mW I can calculate the impedance of the headphone. And the current requirements for each level. And then comparing to the device output current capacity to see if the device is capable.

How is db/mW measured? Is it with or without pads (distance based)? I ask because it is standardized by distance with speakers. However, headphone pads change the distance from ears and perceived volume drastically, so I have tended to ignore these values in headphones.....

 

[andreasmaaan]

How is db/mW measured? Is it with or without pads (distance based)? I ask because it is standardized by distance with speakers. However, headphone pads change the distance from ears and perceived volume drastically, so I have tended to ignore these values in headphones.....

With pads, at the mic location in the dummy pinna, I believe.

 

[Hugo9000]

@StevenEleven Bose revenue in 2017: $3.8 billion. Hardly an underdog lmao.

 

[StevenEleven]

@StevenEleven Bose revenue in 2017: $3.8 billion. Hardly an underdog lmao.

I know. I thought of that as I was writing it. It was a rhetorical flourish, what can I say.

 

[jsrtheta]

I think most people will get more for their buck by buying nearly any Bose product than by buying a sonically pointless $350 outboard DAC.

I really like the Bose QC 35 IIs.

I think what they have done with the Soundlnk Color II is very price competitive.

I think using audiophile as a pejorative term can only do harm.

I think the old Bose speaker systems were plenty good to enjoy music on. I think the customer satisfaction and lack of product churn people experienced and continue to experience with Bose is important to acknowledge. I think Bose bashing is as much a product of group think as anything else. If I took the worst products in the history of a company out of any successful company’s product line and used them as illustrative of that company’s flaws would that make any sense?

Also it seems to me C is more interested in science than engineering. With the question being: can ultrasonic frequencies interact with sonic frequencies in such a way as to be audible in music? That’s a legitimate question. Audible frequencies certainly interact with other audible frequencies. I personally don’t think that ultrasonic frequencies will interfere with or alter perception of audible frequencies in music. But I’m guessing and no more. How about you? If not, then answer the guy’s question instead of speaking down to him like you know so much.

Could ultrasonic frequencies ever interfere with the perception of audible frequencies? If you don’t think so, and you acknowledge that sonic frequencies can interact with one another, what is your proof or reasoning, other than mere intuition or opinion? Say what it is!! If you do think so, then what we have here is a question of scientific fact or degree as to whether such an effect could occur in music. I would guess not, with the operative word being guess. Tell me why! Educate us!!

Now we (mostly) all know those ultrasonic frequencies don’t get reproduced on redbook CD and most studio microphones don’t record at those frequencies so there is generally nothing to reproduce up there in a finished recording and that any decently designed DAC is transparent for home audio use. We (mostly) all know that any frequencies we might perceive up in the area of 20 kHz when we are young will nevertheless be very faint in music and probably will be masked by anything that is also going on in music. Why not say that?

When someone on the one hand advocates for buying a sonically pointless $350 outboard DAC and on the other hand casts blanket aspersions on “audiophiles” and “Bose” I look askance at that.

Okay, now you can shoot me. I root for the underdog. It’s my nature.

I'm sorry - "subwoofers" that go all the way down to ...40 Hz? Crap paper divers? Ludicrously limited frequency response? Designed for people in their 80s? That Bose?

And this makes for a serious comment...how?

 

[Thomas savage]

Can we move away from BOSE now please lol

Great NC tech and well built headphones dubious anything else .

We don't need multiple pages of off topic back and forth on this .

Although it's a pleasant distraction from ' science don't explain my audiophile imaginations so science is wrong and must be fixed to comply with me' ...

Maybe carry on with the BOSE theme .