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#11
10-24-2015, 01:45 PM
 George Frankly Member SOA AAA Join Date: Aug 2011 Location: CO Favorite beer: Sam Smith Oatmeal Posts: 10,158

Quote:
 Originally Posted by Incredible Hulctuary But if you're a real audiophile and you read further about it, you'd realize how not-so-good CD audio really is. Although the mathematical principles behind the CD audio format are sound (no pun intended), in practice things don't go so well because the theoretical concepts involved are too computationally expensive to fully implement. The first shortfall in practice compared to the theory is the brick wall filter that is supposed to remove all frequencies above the Nyquist cutoff of 22.05kHz. Without removing those frequencies, one loses the ability to accurately reconstruct the continuous waveform from the discrete 44,100 samples per second. But in reality there is no such thing as a true brick wall filter, i.e. completely removing all frequencies above the cutoff while leaving all frequencies below it untouched. A practical filter is going to introduce some distortion below the cutoff while still leaving something above the cutoff. The human hearing limit of 20kHz is not far below the chosen Nyquist frequency of 22.05kHz, so some filter-induced distortion can still leak into the human hearing range. The second (and bigger) problem is that digital-to-analog converters (DACs) in consumer hardware don't even use the proven math for reconstructing the continuous waveforms, because it's too computationally expensive. Mathematically accurate reconstruction of the waveform would involve sinc functions and Fourier transforms and other math I don't understand, but that's too much for a typical \$10 DAC chip to do in real time so they resort to cheap interpolations instead. The good news is that improvements in technology are enabling the CD format to produce results closer to its theoretical ideal. In the early days of CDs, the brick wall filters were analog, and they introduced lots of distortion into the audible range so CDs back then sounded harsh. But now they're using digital brick wall filters which can perform much closer to the ideal, and they can keep improving those filters by throwing more computational power at them and tweaking the algorithms. On the playback end of it, some high-end DACs are incorporating field-programmable gate arrays (FPGA) so they can be more true to the math that is involved with reconstructing the analog waveform. And there is software like HQPlayer that utilizes the processing power of multi-core PCs to perform that math to upsample to high rates like 192kHz or 384kHz, thereby leaving the DAC with less work to do with filling each gap between samples (provided your DAC can accept a sample rate that high, of course).
I'm not an expert in signal processing, I do agree with some of what you said and can't refute the bits I don't understand! I haven't found analog sources to sound better than CDs, so it's not like I have a better alternative.

I do want a new CD player, mine skips at high SPL. The subs shake it a lot.

I do generally say to put the money in the speakers. Distortion for sources and amps is almost academic, 0.05% or whatever. Speakers have much more. My JBL setup is at about 0.4% THD, subs are often 5% at volume. I generally focus on the drivers, the polar response, and the room. IMO.
#12
10-24-2015, 04:25 PM
 DaveF Member Non-Actuary Join Date: Jul 2003 Posts: 319

I paid \$6,000 for some Brazilian rosewood volume knobs on my pre-amp. I could hear a huge difference in high end sparkle. When combined with the solid gold speaker wires it really put the system over the top.
#13
10-24-2015, 05:01 PM
 George Frankly Member SOA AAA Join Date: Aug 2011 Location: CO Favorite beer: Sam Smith Oatmeal Posts: 10,158

Quote:
 Originally Posted by DaveF I paid \$6,000 for some Brazilian rosewood volume knobs on my pre-amp. I could hear a huge difference in high end sparkle. When combined with the solid gold speaker wires it really put the system over the top.
Nice. I hear Brazilian rosewood really brings out the silence between the notes and improves the pace and rhythm. I was at Rocky Mountain Audio Fest last year and had a conversation with a guy selling amps. He claimed that solder temperature is important. I actually kept a straight face while he prattled on about how 645F sounded a little lifeless, 655F was too bright sounding, and 650F was just right. It was like Goldilocks and the Bears, but less believable.

Did anyone see the Acura 'tube amp' commercial a few years ago. I loved that one.
#14
10-25-2015, 10:40 AM
 Incredible Hulctuary Member Non-Actuary Join Date: Jan 2002 Posts: 25,338

Quote:
 Originally Posted by DaveF I paid \$6,000 for some Brazilian rosewood volume knobs on my pre-amp. I could hear a huge difference in high end sparkle. When combined with the solid gold speaker wires it really put the system over the top.
LoL. Now you just need to add a pair of Shakti Hallograph sound field optimizers to your room and you'll be in audiophile heaven.

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#15
10-30-2015, 04:47 PM
 monkeyunited Member CAS SOA Join Date: Jan 2013 Studying for MFE Favorite beer: Taiwan beer Posts: 152

Quote:
 Originally Posted by George Frankly Nice. I hear Brazilian rosewood really brings out the silence between the notes and improves the pace and rhythm. I was at Rocky Mountain Audio Fest last year and had a conversation with a guy selling amps. He claimed that solder temperature is important. I actually kept a straight face while he prattled on about how 645F sounded a little lifeless, 655F was too bright sounding, and 650F was just right. It was like Goldilocks and the Bears, but less believable. Did anyone see the Acura 'tube amp' commercial a few years ago. I loved that one.
You can't be serious..
#16
11-02-2015, 12:18 PM
 George Frankly Member SOA AAA Join Date: Aug 2011 Location: CO Favorite beer: Sam Smith Oatmeal Posts: 10,158

Quote:
 Originally Posted by monkeyunited You can't be serious..
Not about the rosewood. But totally serious about the solder, the guy was really trying to sell it.
#17
07-24-2016, 03:48 PM
 George Frankly Member SOA AAA Join Date: Aug 2011 Location: CO Favorite beer: Sam Smith Oatmeal Posts: 10,158

Picked up a JTR Orbit Shifter sub. Horn-loaded 18" with a 4kW amp. It's terrifying, I've never heard a sub with this kind of output. I had an SVS PB-13, the biggest one SVS builds. The JTR is on another level altogether. One problem: wiring. This thing needs its own 40A service. It dims all the lights when you crank it. On a 15A breaker I'm limited to maybe 2kW.

Here's the link. Yes, it's rather large. TWSS.

http://jtrspeakers.com/home-audio/orbit-shifter-lfu/
#18
07-24-2016, 08:23 PM
 DiscreteAndDiscreet Member AAA Join Date: May 2016 Posts: 478

Quote:
 Originally Posted by George Frankly Picked up a JTR Orbit Shifter sub. Horn-loaded 18" with a 4kW amp. It's terrifying, I've never heard a sub with this kind of output. I had an SVS PB-13, the biggest one SVS builds. The JTR is on another level altogether. One problem: wiring. This thing needs its own 40A service. It dims all the lights when you crank it. On a 15A breaker I'm limited to maybe 2kW. Here's the link. Yes, it's rather large. TWSS. http://jtrspeakers.com/home-audio/orbit-shifter-lfu/
This might be a time when it might be appropriate to open up your house's breaker box and look at the ratings on the breakers for things such as HVAC and heavy appliances and then spend a few quiet moments in contemplation of what work those devices accomplish with those amps and how that compares to a device that generates sound in a particular range of frequencies.

You're talking about something that is a bit outside of the scale of things that are usually installed in residentially zoned buildings.
#19
07-24-2016, 10:03 PM
 George Frankly Member SOA AAA Join Date: Aug 2011 Location: CO Favorite beer: Sam Smith Oatmeal Posts: 10,158

Quote:
 Originally Posted by DiscreteAndDiscreet This might be a time when it might be appropriate to open up your house's breaker box and look at the ratings on the breakers for things such as HVAC and heavy appliances and then spend a few quiet moments in contemplation of what work those devices accomplish with those amps and how that compares to a device that generates sound in a particular range of frequencies. You're talking about something that is a bit outside of the scale of things that are usually installed in residentially zoned buildings.
Eh. It's just a hobby. Will be fun at our neighborhood block party in a few weeks. Well, cranking it up will be fun. Moving a 220lb box out of the house and back in wont be all that much fun.
#20
07-25-2016, 12:43 PM
 ahow Member CAS Join Date: Nov 2003 Location: Burninating the Indiana Favorite beer: Stone 11th Anniversary Ale Posts: 12,328

It may sound odd, but you might look into welding websites for tips on wiring up something with that kind of draw. Welding machines run in the 50-75A range for a higher end models, I believe.

Depending on how things are set up, you may want to run a 220v line to it which will reduce the amperage requirement and reduce the amount of heat generated. Reduced heat will probably also extend the life of the amp.
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