Ask an Audio geek

[Kosh]

I need to get out of the political forum for a bit, so lets talk about Digital Music  
  
As we've established, CD is a superior format over vinyl when it comes down to the measurable specs.   The problem with CD isn't in the format, but in the mastering process.  In the mid 1990's we started to see the "Loudness War" take hold. 
  
https://en.wikipedia.org/wiki/Loudness_war  
  
I am personally very sensitive to the effects of the Loudness War, and is the main reason I started getting back into Vinyl about 10 years ago.  In my opinion, music from a hearing perception point of view is that it sounds flat.  Listening to this compressed flat sound for even a little while causes me to become restless.  Even songs I like are not enjoyable.  I believe it's the lack of dynamic range that is the culprit.

This is an interesting website http://dr.loudness-war.info/ 
 
It's a database of measured dynamic range from music in a variety of different formats.  The larger the numbers, the higher the dynamic range.  Dynamic range is simply the difference between the softest sound to the loudest.  The scale ranges from 1 (BAD) to 20 (GOOD).   It's interesting to compare CD's that you feel sound good to ones that you don't.  Vinyl isn't perfect in this regard.  Much of the new Vinyl being pressed uses the same crappy master that was used for the CD, but they do have to tweak the levels so the record is actually playable. 

The we have Hi-Rez music which I'll leave for another day.  Some people feel it's useless and beyond the range of human hearing.  Some people swear by it.  My personal opinion is that they do sometimes sound better, but not because of the extra frequency/bit rate.

The loudness war and problems with the mastering process is something one could "illustrate" using some samples, since it doesn't depend on super high level conversion and shouldn't be messed up too badly by mp3 compression.

From what you say, I suspect that classical music recordings are not as badly affected as pop/rock, right?

I would definitely agree with you Alex. Pop and rock (metal, rap) are the major offenders. I like jazz and have never had an issue with modern recordings. I'm guessing classical music is in the same group.

[AFTT47]

As we've established, CD is a superior format over vinyl when it comes down to the measurable specs.   The problem with CD isn't in the format, but in the mastering process.  In the mid 1990's we started to see the "Loudness War" take hold. 
  
https://en.wikipedia.org/wiki/Loudness_war  
  
I am personally very sensitive to the effects of the Loudness War, and is the main reason I started getting back into Vinyl about 10 years ago.

How does switching to vinyl help? If masters exist which are free from coloration, why not just record them onto a CD? What's the point of recording them onto a vastly inferior format? Or is it the same master and the coloring effects inherent in vinyl neutralize the offending qualities of the master?

[JuliaL]

I just purchased a pair of 1979 EPI 100Ws for $5.....woot.

Their 8" drivers need to be re-foamed.  I've done this before (Cerwin Vega) but:

Question 1:
How much is this likely to affect their performance?  I understand that their original design depended on the mechanical characteristics of the drivers rather than an L/C crossover to separate the low and high frequencies.  Clearly the foam I can buy on E-bay isn't from the manufacturer.  But is it close enough?

Question 2:
What is a good way to check against the 'as new'?  I've accumulated enough hardware to measure me a Bode plot.  But I have no idea what it should have looked like from the factory.  I have a darkly humorous anecdote about frequency response in modern vs antique test equipment, but I don't want to put it on the internet as it is slightly disrespectful of Nissan engineers.

[ignoramus]

I've replaced the foam surrounds with good rubber ones.
I didn't notice much difference because it was only on the bottom 2 12 inch active thumpers.
They were good 20 20 speakers (+/- 3db). DB1212

Foam is cheaper but that doesn't necessarily mean they're not good speakers. Sometimes they need the quick response of the foam. The speakers were heavily used for over 10 years though so not complaining.

Sold them for $800 15 years later!

[Alex K]

I just purchased a pair of 1979 EPI 100Ws for $5.....woot.

Their 8" drivers need to be re-foamed.  I've done this before (Cerwin Vega) but:

That is so sexy.

[Goosebump]

I'm an avid audio geek and music fan.  I've been into audio gear and music since I was in my teens.  I purchased my first decent stereo when I was 14 (1982), and I spent over $1000 at the time.  I've been obsessed ever since.  I sold high end gear in the early 90's, and know a bit about audio engineering from friends and acquaintances.

I can tell you where the sweet spot is, and what is snake oil.

I also have an IT background so I've built a fair amount of HTPC's.

Fire away..

Can you answer anything I couldn't google myself and if so what would that be? Other-words: what questions would I not search for?

[ignoramus]

[Kosh]

As we've established, CD is a superior format over vinyl when it comes down to the measurable specs.   The problem with CD isn't in the format, but in the mastering process.  In the mid 1990's we started to see the "Loudness War" take hold. 
  
https://en.wikipedia.org/wiki/Loudness_war  
  
I am personally very sensitive to the effects of the Loudness War, and is the main reason I started getting back into Vinyl about 10 years ago.

How does switching to vinyl help? If masters exist which are free from coloration, why not just record them onto a CD? What's the point of recording them onto a vastly inferior format? Or is it the same master and the coloring effects inherent in vinyl neutralize the offending qualities of the master?

That's the thing.  In many cases with newer material, a master doesn't exist that is free from the effects of the loudness war.   This isn't an issue inherent in the CD format.  The choice to compress the dynamic range and use brick-wall limiters is a conscious decision by the recording "engineer" and the artist.  It's basically an exercise in psychoacoustics, and is the same reason why some commercials are MUCH louder than the TV show they accompany.  It's an attention getter.  The same holds true for music on the radio or streaming.  The human mind thinks that louder = better, and this is a big reason why level matching is important when doing A/B comparisons with audio gear.

How does switching to Vinyl help?  
  
1) Vinyl has becomes a premium priced (aka expensive) niche market.  I think the general consensus is that people who listen to vinyl care more about how their music sounds.  Your not listening to your vinyl on a phone with cheap earbuds.  The good Artist/record labels will actually go back to the original recording tracks (before the mastering process), and create a vinyl specific master that is free from dynamic range compression and excessive volume levels.  
 
2) The vinyl medium has limitations on how loud the audio can that recorded is not present in digital.  The record would literally be unplayable if they attempted to create a 1:1 copy between a CD and a record.  The cutting lathe use to create the vinyl master would cut through the acetate master blank.  Sometimes a record label will go the cheap route in a cash grab and use the digital master.  They take the same master used for the CD, reduce the volume level, and apply RIAA equalization.  These records still sound like crap, but IMO are generally more listenable than the CD.

---

I'm an avid audio geek and music fan.  I've been into audio gear and music since I was in my teens.  I purchased my first decent stereo when I was 14 (1982), and I spent over $1000 at the time.  I've been obsessed ever since.  I sold high end gear in the early 90's, and know a bit about audio engineering from friends and acquaintances.

I can tell you where the sweet spot is, and what is snake oil.

I also have an IT background so I've built a fair amount of HTPC's.

Fire away..

Can you answer anything I couldn't google myself and if so what would that be? Other-words: what questions would I not search for?

In all honesty.  I think the only thing that I can give you that google can't is my opinion.

[IATIA]

Do your commercial systems even have unbalanced inputs?

I have a choice.

[Kosh]

I just purchased a pair of 1979 EPI 100Ws for $5.....woot.

Their 8" drivers need to be re-foamed.  I've done this before (Cerwin Vega) but:

Question 1:
How much is this likely to affect their performance?  I understand that their original design depended on the mechanical characteristics of the drivers rather than an L/C crossover to separate the low and high frequencies.  Clearly the foam I can buy on E-bay isn't from the manufacturer.  But is it close enough?

Question 2:
What is a good way to check against the 'as new'?  I've accumulated enough hardware to measure me a Bode plot.  But I have no idea what it should have looked like from the factory.  I have a darkly humorous anecdote about frequency response in modern vs antique test equipment, but I don't want to put it on the internet as it is slightly disrespectful of Nissan engineers.

In regards to question 2.  The frequency response across the crossover point should be fairly flat.  If the driver characteristics changes to a large degree, you'll see either a spike or a valley at the crossover point between the woofer and the tweeter.  A spike represents an increase is frequency extension (both drivers are playing that frequency range), and a valley would be a degrease (neither driver is playing that frequency range).  I'm not sure of a good tool to measure this would be.  I have an Anthem MRX receiver that came with a calibrated microphone and software that can do this.

---

I just purchased a pair of 1979 EPI 100Ws for $5.....woot.

Their 8" drivers need to be re-foamed.  I've done this before (Cerwin Vega) but:

Question 1:
How much is this likely to affect their performance?  I understand that their original design depended on the mechanical characteristics of the drivers rather than an L/C crossover to separate the low and high frequencies.  Clearly the foam I can buy on E-bay isn't from the manufacturer.  But is it close enough?

Question 2:
What is a good way to check against the 'as new'?  I've accumulated enough hardware to measure me a Bode plot.  But I have no idea what it should have looked like from the factory.  I have a darkly humorous anecdote about frequency response in modern vs antique test equipment, but I don't want to put it on the internet as it is slightly disrespectful of Nissan engineers.

In regards to question 2.  The frequency response across the crossover point should be fairly flat.  If the driver characteristics changes to a large degree, you'll see either a spike or a valley at the crossover point between the woofer and the tweeter.  A spike represents an increase is frequency extension (both drivers are playing that frequency range), and a valley would be a decrease (neither driver is playing that frequency range).  I'm not sure of a good tool to measure this would be.  I have an Anthem MRX receiver that came with a calibrated microphone and software that can do this.