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Re: Audiophilia nervosa

Wed Aug 24, 2016 2:08 pm

morphine wrote:
Honest question, why would the termination make any difference, assuming the wire is making proper contact?

If you're shoving bare wire through the terminal hole and cranking down the screw, none. If you like banana plugs like me, quality terminations can withstand many more disconnect/reconnects than cheaply-done ones. Since the speakers get moved on a somewhat-regular basis to clean the room, the quality terminations will aid in the long run.
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Re: Audiophilia nervosa

Wed Aug 24, 2016 2:11 pm

Oh. My speakers don't get moved.

The last time one of them did, it was at a rather high velocity and impacting the tile floor. Speaker is fine but the front cover's latches snapped. Ever being the lazy DYI'er, I didn't really secure it in place, just added some padding so it at least stays put if nobody touches it.

Of course, any "audiophile" will read the above and say that I've completely ruined the speaker's sound somehow. (And yes, I did actually listen for any difference.)
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Re: Audiophilia nervosa

Wed Aug 24, 2016 2:27 pm

morphine wrote:
Honest question, why would the termination make any difference, assuming the wire is making proper contact?


That highlighted part is the key. Current carrying capability is directly dependent on contact surface area. Solder terminations give the most surface contact, and least resistance, between the wire and whatever is on the end. Spades give the most surface contact between the termination and the speaker terminal -- flat surface to flat surface.

For big speakers driven with a lot of power, it gets more power to the drivers.

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Re: Audiophilia nervosa

Wed Aug 24, 2016 2:42 pm

Smaller (and not soldered) contact areas also increase the risk of corrosion of the metal surfaces causing the connection to act like a crude point contact diode. This can introduce some pretty nasty harmonic distortion.
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Re: Audiophilia nervosa

Wed Aug 24, 2016 2:48 pm

Interesting replies and data, thanks.

I don't think it makes any difference for me since they're small speakers and stuff is screwed down pretty hard. Having said that, if I ever mess with the cables again, I'll probably solder the ends just because.
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Re: Audiophilia nervosa

Wed Aug 24, 2016 3:32 pm

morphine wrote:
Interesting replies and data, thanks.

I don't think it makes any difference for me since they're small speakers and stuff is screwed down pretty hard. Having said that, if I ever mess with the cables again, I'll probably solder the ends just because.

FWIW, I only recommend doing that for tinned copper wires. Years ago I discovered, the first time I started using clear-jacketed speaker wire, that soldering to un-tinned copper can be a bad idea because the wire is manufactured with a very thin protective coating on the wire, which burns off when you solder to it. The wire then starts corroding and may continue doing so down into the jacket, which was also loosened a bit by the heat.  Some type of crimp or screw-down copper compression connector is much more reliable.

As an additional data point, in power system controls and industrial controls it is standard practice to terminate field cables and wire jumpers (from both tinned copper wires, and untinned coated copper wires) using high-quality, tinned-copper compression connectors, and this is done and left in the field for years.  These connections are durable and reliable even when high current or low voltage has to be carried by the terminal, i.e. any appreciable termination resistance will either heat and burn, or degrade the signal quality.

The urge to solder All The Things can actually be counterproductive in some applications.
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Re: Audiophilia nervosa

Wed Aug 24, 2016 4:13 pm

ludi wrote:
FWIW, I only recommend doing that for tinned copper wires. Years ago I discovered, the first time I started using clear-jacketed speaker wire, that soldering to un-tinned copper can be a bad idea because the wire is manufactured with a very thin protective coating on the wire, which burns off when you solder to it. The wire then starts corroding and may continue doing so down into the jacket, which was also loosened a bit by the heat.  Some type of crimp or screw-down copper compression connector is much more reliable.

As long as you're careful to trim it back an inch or so (past the corrosion) if you ever decide to re-terminate or go back to a bare wire connection, a little corrosion on the outside of the conductor shouldn't matter.
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Re: Audiophilia nervosa

Wed Aug 24, 2016 8:04 pm

ludi wrote:
[FWIW, I only recommend doing that for tinned copper wires. Years ago I discovered, the first time I started using clear-jacketed speaker wire, that soldering to un-tinned copper can be a bad idea because the wire is manufactured with a very thin protective coating on the wire, which burns off when you solder to it. The wire then starts corroding and may continue doing so down into the jacket, which was also loosened a bit by the heat.  Some type of crimp or screw-down copper compression connector is much more reliable.

A common problem with the original Monster Cable. Wasn't at all uncommon to see green all the way through after a few years in a humid climate.
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Re: Audiophilia nervosa

Wed Aug 24, 2016 10:34 pm

I usually solder but mostly because I usually use cheap gold plated Radio Shack spade lugs. If I had a good crimper or spent money on compression or set screw terminals I would not solder.

But on to the Nervosa, look at speaker building. That is a very complex rabbit hole. The electronics side is pretty well figured out but speakers themselves can have a huge impact on sound.

I would not feel too bad about spending $3,000 or more to make a set of line arrays with a crossover of my own design and I'm sure it would make an audible difference. I think it would be a good one.

The important thing about it is that when you see what is inside a speaker and how the dimensions, diffraction, phase, cross over, time alignment and everything else affect the sound, you will realize once the electronics are good enough you can quit worrying about everything up to the speaker.

People are getting good sound from $20.00 Chinese class D amps fed by a $30.00 USB DAC so its not required to spend a lot for the electronics.

Speakers on the other hand are made with big parts that are just expensive if you want quality.

Bose did an interesting thing, they made a killing selling $2.00 speakers with a few opamps to equalize the response. The secret sauce was high spousal approval factor.

If you aren't willing to settle for Bose level sound it is going to get expensive.
 
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Re: Audiophilia nervosa

Wed Aug 24, 2016 10:50 pm

Frugal wrote:
But on to the Nervosa, look at speaker building. That is a very complex rabbit hole. The electronics side is pretty well figured out but speakers themselves can have a huge impact on sound.

I would not feel too bad about spending $3,000 or more to make a set of line arrays with a crossover of my own design and I'm sure it would make an audible difference. I think it would be a good one.

The important thing about it is that when you see what is inside a speaker and how the dimensions, diffraction, phase, cross over, time alignment and everything else affect the sound, you will realize once the electronics are good enough you can quit worrying about everything up to the speaker.

And how do you plan on testing this speaker for designed vs actual crossover frequency response or nasty cabinet resonances? Speakers are not just a box into which ones throws crossovers and drivers and "magic!!".
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Re: Audiophilia nervosa

Wed Aug 24, 2016 11:01 pm

Captain Ned wrote:
And how do you plan on testing this speaker for designed vs actual crossover frequency response or nasty cabinet resonances? Speakers are not just a box into which ones throws crossovers and drivers and "magic!!".

This is where the real magic is - speakers.

Amplifiers and everything feeding them has been good enough for human ears for at least two decades. Speakers have been the weakest link for a long time, and they're by far the most complicated parts.

I know I'll never have the ears to appreciate truly good speakers (too many years of 140+ dB systems), but I can pick out things that bug the hell out of me in cheap sets. These days, I've been chasing subsonics. The WAF is low, but thankfully I have a crazy wife. I can build decent subwoofer setups, since they're far simpler than even the most basic multi-way full range speaker build.

One of the guys we had interview in the past 6 months had a hobby of modeling and building full range speaker cabinets + crossovers. Pure freakin' magic, I would have hired him simply because anyone willing to delve into that level of detail to do things properly is going to pay attention to the details that matter doing their job as well. :lol:


Electrostatics seem to be the only way to cheat the system, and even then, they aren't simple.
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Re: Audiophilia nervosa

Wed Aug 24, 2016 11:49 pm

Waco wrote:
[Amplifiers and everything feeding them has been good enough for human ears for at least two decades. Speakers have been the weakest link for a long time, and they're by far the most complicated parts.

It's why I will always shun the DIY in favor of a mfg who can actually test the beasties and tweak the design before putting them on sale,
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Re: Audiophilia nervosa

Thu Aug 25, 2016 1:00 am

Captain Ned wrote:
Waco wrote:
[Amplifiers and everything feeding them has been good enough for human ears for at least two decades.  Speakers have been the weakest link for a long time, and they're by far the most complicated parts.

It's why I will always shun the DIY in favor of a mfg who can actually test the beasties and tweak the design before putting them on sale,

alloyD's post about the Overnight Sensations has me considering the DIY if the payoff is worth it.
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Re: Audiophilia nervosa

Thu Aug 25, 2016 3:34 am

Captain Ned wrote:
And how do you plan on testing this speaker for designed vs actual crossover frequency response or nasty cabinet resonances?  Speakers are not just a box into which ones throws crossovers and drivers and "magic!!".

Having designed and built several speakers systems entirely from scratch, the answer is "books" and "computers." Modern speaker design is nothing like the "best-guess-and-measure-the-prototype" design rules of the 1970s and 1980s (of which I still have one such book on my shelf).  Between a more modern book resource like Vance Dickason's Loudspeaker Design Cookbook, the free WinISD software, and the good folks at Parts Express, a from-scratch 2-way or even 3-way design is well within reach of a reasonably well-researched enthusiast.

I have a pair of dual-8", 3-way/4-driver ported towers that were designed and built using the above and helpful advice from experienced builders on a lesser-known DIY audio forum.  The published T-S and frequency response parameters for the drivers, and the resulting design math, said the complete system would output about 32-25kHz with a flat response across the range.  When my aforementioned audiophile coworker brought over his own test gear and we measured them, we got 28Hz (which included a bit of room gain) to >22kHz (limited by his equipment), and response to within +/-1dB across the range.

Low-cost iterative simulations FTW.
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Re: Audiophilia nervosa

Thu Aug 25, 2016 7:56 am

Getting the frequency response (completely flat isn't always the objective for hifi speakers - but this is another debate) is only one, albeit important, part of speaker design. A part that is largely addressed by a properly designed crossover in 2-way+ systems. You can get frequency-dependent distortion from cabinet resonances (yes, this often presents as higher sound pressure for certain frequencies in question, bit is really a different issue from flat frequency response of the cross-over/driver/cabinet tuning parameters). Then there are aspects such as attack and decay (ie, responsiveness of the combined driver system), off axis frequency response, and timber (mostly important in the higher frequencies) - and example of the importance of timbre is how some people prefer characteristic sound of frabric vs metal tweeters, etc. Or dome vs ribbon.
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 2:42 pm

Interesting "turn" of the topic.

I've been designing loudspeakers for over 15 years now.  It's both difficult and easy..  I've seen one designer pick-up not only everything to craft a competent loudspeaker within about 3 months, but also some significantly intricate and not-well-known design details to improve performance.  He has continued-on from there and is perhaps one of the best loudspeaker designers today (and by-and-large he is still an "amateur" producing for DIY, not profit). 

I think most are on the "other end" of the spectrum however, just finding it difficult to use the software and testing equipment necessary for well designed speakers.  Even then, there are a lot of details that are into the "voodoo" category that most good designers either don't know about, or don't give enough "weight" to their finished designs.  

It's *usually* not an easy process to produce a really good loudspeaker. I even cringe at some of the design choices in some of the best *regarded* loudspeakers in the market.


BTW, while the largest contributor to sound is the loudspeaker (even well beyond that of the environment it's reproducing sound in - to a point), the other components are also very important in my experience. And to bring this thread "full circle", Power Supplies in particular (to each component) seem to be one of the largest determinate(s) of improved (or reduced) performance with these other components.
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 2:52 pm

cynan wrote:
Getting the frequency response (completely flat isn't always the objective for hifi speakers - but this is another debate) is only one, albeit important, part of speaker design. A part that is largely addressed by a properly designed crossover in 2-way+ systems. You can get frequency-dependent distortion from cabinet resonances (yes, this often presents as higher sound pressure for certain frequencies in question, bit is really a different issue from flat frequency response of the cross-over/driver/cabinet tuning parameters). Then there are aspects such as attack and decay (ie, responsiveness of the combined driver system), off axis frequency response, and timber (mostly important in the higher frequencies) - and example of the importance of timbre is how some people prefer characteristic sound of frabric vs metal tweeters, etc. Or dome vs ribbon.

Yes, there a number of other things which were considered and went into the design, but for home hi-fi if the output is reasonably flat across the range, then you've generally done a pretty good job of sizing the cabinet and port, damping the internals, overlapping the crossover points, etc.  The resources which are now available to even relative novices are quite amazing, thanks to cheap computing power.  While people certainly can throw things together and hope for the best (and probably not get it), there's no reason why they would have to do so: the tools are available.
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Re: Audiophilia nervosa

Thu Aug 25, 2016 2:56 pm

Seems to me that with today's sophisticated DSP tech, one could take the Bose approach a step further, and build a "good enough" driver/crossover/cabinet combo, with a signal processor to be inserted somewhere upstream which would precisely alter the signal to compensate for any peaks, dips, distortions, or phase shifts in the response. As an added bonus, with suitable on-site testing you could compensate for room acoustics as well.

Has anyone tried this approach?
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Re: Audiophilia nervosa

Thu Aug 25, 2016 3:09 pm

just brew it! wrote:
Seems to me that with today's sophisticated DSP tech, one could take the Bose approach a step further, and build a "good enough" driver/crossover/cabinet combo, with a signal processor to be inserted somewhere upstream which would precisely alter the signal to compensate for any peaks, dips, distortions, or phase shifts in the response. As an added bonus, with suitable on-site testing you could compensate for room acoustics as well.

Has anyone tried this approach?

Many have, and you can yourself.  In fact with the right resources it's a lot easier to design a loudspeaker this way - plus there are some very good amplifiers that can be "DIY" sourced (considering it's an "active" solution: one where each driver "channel" is driven by an amplifier).
MiniDSP is probably the easiest solution (with enough channels-out for the number of total "channel" drivers: ie. two-way loudspeakers require 4 channels/outputs).
https://www.minidsp.com/
I use Soundeasy for prototyping so I can make adjustments "on-the-fly" to get it just the way I want before converting over to a passive design.
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 4:44 pm

I have thought about using active crossovers and Linkwitz transforms to perfectly shape the crossover region for a speaker but if you try to avoid crossing over at the voice frequency range and have enough drivers to deliver a large SPL at low frequencies, you wind up with lots of little drivers and lots of amplifiers to drive them ~individually.

That is why I would have to spend so much on a set of line arrays even if I was buying relatively cheap drivers.  It is also hard to find cheap tweeters that don't have ferofluid.

There is always the same sonic goal for a speaker and many design strategies that people try to get there but there is usually a point they can get to which is very good but still lacking in one or more areas.  Line array is extreme but it can satisfy a lot of the requirements for perfect sound reproduction, I just don't think anyone has done it quite right yet (but I have a plan).
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 5:47 pm

Frugal wrote:
I have thought about using active crossovers and Linkwitz transforms to perfectly shape the crossover region for a speaker but if you try to avoid crossing over at the voice frequency range and have enough drivers to deliver a large SPL at low frequencies, you wind up with lots of little drivers and lots of amplifiers to drive them ~individually.

That is why I would have to spend so much on a set of line arrays even if I was buying relatively cheap drivers.  It is also hard to find cheap tweeters that don't have ferofluid.

There is always the same sonic goal for a speaker and many design strategies that people try to get there but there is usually a point they can get to which is very good but still lacking in one or more areas.  Line array is extreme but it can satisfy a lot of the requirements for perfect sound reproduction, I just don't think anyone has done it quite right yet (but I have a plan).

You don't need to do that if you have good digital eq. capability.  Just a bunch of small full range drivers operating from about 150 Hz up with a single amplifier for that channel (..specifically NOT needing to power each driver). You will need to power the region below 150 Hz of course with its own bass driver(s).
You will end-up with combing effects at higher freq.s even with freq. shaping via eq. - but more than a few people like this effect because it presents a flavor of sound similar to an electrostat.
A very good driver for this application (digital eq. fullrange driver line array):
http://www.parts-express.com/peerless-b ... --264-1144
You can see detailed measurements here:
http://www.zaphaudio.com/blog.html
(..of course "fullrange" driver isn't correct, but it's what the industry calls them.)
The best paper on Line Arrays:
http://www.audioroundtable.com/misc/nflawp.pdf
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 5:52 pm

Oh, my inner hair-shirt (1st-order/time-aligned) is freaking out right now.

That said, I need to hear myself some vintage Quads (ESL-57 or ESL-63) just to grok why the boomers who make up the audiophile press (such as it is) so revere the bloody things.
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Re: Audiophilia nervosa

Thu Aug 25, 2016 5:54 pm

@CScottG - EQ doesn't correct frequency-dependent phase shift errors (and may even introduce them). Aside from simple polarity reversal (which is a case of "If it hurts when you do that, stop!"), for phase shift you need some more esoteric voodoo (which I suspect is easier to do with DSPs than in physical hardware).
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Re: Audiophilia nervosa

Thu Aug 25, 2016 6:02 pm

Haha, line arrays. Anyone that's ever made PA live sound would tell you not "there be dragons here," but something more along the lines "there are so many dragons in there they've taken to calling me Khaleesi."
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Re: Audiophilia nervosa

Thu Aug 25, 2016 6:06 pm

Yeah, PA is going to be a clusterf*ck for at least some subset of the audience no matter how you slice it. Even with infinite EQ/DSP capabilities and the best equipment, you can only optimize for certain points in a listening space.
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Re: Audiophilia nervosa

Thu Aug 25, 2016 6:09 pm

morphine wrote:
Haha, line arrays. Anyone that's ever made PA live sound would tell you not "there be dragons here," but something more along the lines "there are so many dragons in there they've taken to calling me Khaleesi."

Well, it's not as if anyone was trying to turn the Infinity IRS-V into a PA system. Oh wait, that's exactly what the Grateful Dead tried to do with the Wall of Sound.
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Re: Audiophilia nervosa

Thu Aug 25, 2016 6:38 pm

just brew it! wrote:
@CScottG - EQ doesn't correct frequency-dependent phase shift errors (and may even introduce them). Aside from simple polarity reversal (which is a case of "If it hurts when you do that, stop!"), for phase shift you need some more esoteric voodoo (which I suspect is easier to do with DSPs than in physical hardware).

Digital eq., not analog.
There's phase, and then there's phase, and then there's phase.

In any event, you still won't get a system without phase errors because while you can digitally eq. over multiple points you can't correct the driver's modal behavior (that generates a "spikey" freq. response at higher freq.s and is constantly shifting - and this assumes that your display of the freq. response isn't averaged so that you can see it ..or isn't averaged much). With an array you'll also get multiple time arrival differences with resulting phase difference for a given measurement point - but they are slight.

Here is a good example without the high-pass filter for the array:
http://projectgallery.parts-express.com ... ine-array/

..note the step response of the array (pic. 14).  Also the problem with diffraction/acoustic gain with so many drivers generating a non-flat freq. response that needs eq. (pic. 10).

None of it's terribly relevant for most design's though, most of the emphasis is placed on excess phase behavior - and then you are concerned with the high-pass filter for the array. A digital eq. system like the minidsp can correct for this around the crossover freq.; also it's useful to do corrections around this range of freq.s because of the phase rotation the driver naturally has near the driver's fs - particularly if pressure-driven (..and a small fullrange driver typically has an fs near these freq.s).  
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 7:11 pm

Captain Ned wrote:
Oh, my inner hair-shirt (1st-order/time-aligned) is freaking out right now.

That said, I need to hear myself some vintage Quads (ESL-57 or ESL-63) just to grok why the boomers who make up the audiophile press (such as it is) so revere the bloody things.

A vertical stack of refurbished ESL-57's sound good, really good.  Of course objectively they aren't that good, particularly when two are used in a vertical stack.
They are also very limited in sound pressure level, best only used in a quiet environment (one that's well isolated).
I've also like several of the larger Martin Logans and Sound Labs.  Final was also good. Acoustat: not-so-much. (..and I've never heard the large Stax loudspeakers or the ones from Metaxis.) The newer Quads don't sound as good, but measure better.
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 8:06 pm

Traditional line arrays run in to all of those problems but all of those problems have a solution.

I think the phase problem you speak of is diffraction caused by driver spacing.  That is a very real problem because an ideal line source has a maximum driver spacing and line length for every frequency.  One of my tricks will be to make the line array act shorter depending on frequency.  At the highest highs it will act nearly like a point source.

Phase coherency is a big deal and has been tackled in passive crossover speakers by designs like filler driver 3 ways.

With drivers that are relatively linear an octave or so past the crossover point, a Linkwitz transform can create a perfect second order crossover slope on both drivers with identical f3.  I think I saw a phase shift circuit also which should be able to line up any remaining mismatch at the cross over.

Some people love first order crossovers but you need flat response so far out from the crossover point that you almost certainly run in to some driver uglieness.

Second order is less forgiving but mainly because drivers are not ideal.  Once you use a Linkwitz transform to give an idea frequency response and Q=0.5, the uglies go away.

Look here:  http://www.linkwitzlab.com/filters.htm#9
 
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Re: Audiophilia nervosa

Thu Aug 25, 2016 8:57 pm

Good Jesus, I'm learning more about sound and speaker design then I care to know. All I know now is that I brought a pair of Flips Audio Headphones from Walmart three years ago, and they sound great in speaker mode even with onboard audio.

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