John Curl's Blowtorch preamplifier part II

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A very gray area ... the system at the moment is a very basic tweaked HT setup, with a proper, self-powered subwoofer. The latter covers up to about 180Hz, and for quite some time the subwoofer was out of the picture, because of experiments I was doing. Yet the mind quickly adjusted to the complete absence of material in those bottom octaves, the music came across as being totally intact, I didn't constantly feel that there was something missing. When it came back it immediately rounded things out, of course, but it is not essential ...

Edit: when I went to the recent hifi show, there were monster subwoofers and humongous bass drivers galore, but never once did I say to myself, "Now, thaaat's bass!!" ...

Frank
 
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Frank,
I am going to assume that your main speakers do have bass output and the subs are just supplemental for the low bass. If you were missing everything below 180hz you would be one unhappy camper...... So how low do your main speakers go is the real question, as you seemed to be able to listen with just those speakers?
 
They are just PC speaker sized enclosure, 3" full ranges ported at the back. The main unit does filter output to them, probably 12dB/octave high pass, I haven't checked the precise details. At one stage I was running some frequency sweeps and the subjective crossover was quite a high bass frequency.

So, there would be some output from below 180Hz because the slope isn't a brickwall, but nothing to write home about ...

For me, the impact of the bass comes from the "bite" of the note, which is a higher frequency thing. A recording that I enjoy is a live version of "Crossroads" by Cream, and Jack Bruce absolutely pumps the song along at seemingly a ferocious number of knots, well back in the centre of the stage. That's the sort of bass I enjoy, and most systems don't get this right ...

Frank
 
I was intrigued ... so just tried this exercise - main system is dead at the moment, it's tired and weary, too many years on the road, too many transplants, I'll have to decide whether one more resuscitation is worth it, :) - on the PC. Grabbed the Cream track, brickwalled everything below 180 or so Hz, which it had plenty of, in Audacity; and then played, normal vs. nothing below 180Hz, versions on just the PC monitors which are actually quite similar to the main speakers.

Obviously different, more meat on the bones with full spectrum, but again quite easy to tune into the bassless version, the song hadn't been destroyed - the brain was "filling in the gaps" with no difficulty ... Jack Bruce was still there ... ;)

Frank
 
Frank, I can tell you that you would have had to cut off one of Jack Bruce's fingers to not get the E string at 41hz open when he is slapping that bass guitar. A six string bass guitar is doing about 30hz on the bottom with an open string. So you are missing way to much music with Cream that is for sure.

ps. Ginger baker wouldn't be any to happy either..........
 
In the '60s, a series of German/British co-production movies was made of Edgar Wallace stories, broadcasted on German TV several times.
Not cinematographic highlights, but the ones which included Klaus Kinski were really spooky, time and again.

Sorry, that guys phono really falls apart at the good part. You need to get the LP on a real system.

Herzog + Kinski can't beat it.
 
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MBL have tape dubs of master Beatles, Led Zepplin, Talking Heads, etc tracks. I was shocked, hi def downloads had nothing on these for dynamics and lack of grain etc, low level resolution , instrumental and vocal detail, ...wow was everyone's reaction... New York audio / video show in April will have MBL 7.1 system with 4 JL Audio Gothams, and Sony 4K projector with Sony 4 K video masters - line up now you've never seen or heard something this good.....

The Constellation Audio gear sounded flat through lower range Magico speakers - sorry John I wanted to like it, but the speakers suck!
 
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Hmmm, repeating yourself there ... :D

There's nothing magical about the tape playback, that's just undistorted sound you're listening to. Possible with all sorts of media, providing all the gremlins are tracked down and kicked out.

The point being, once you hear the "good stuff" everything else is just, effectively, second rate from then on ... don't listen if you don't want to be 'infected' ... :p

Frank
 
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The compressed content you referred to has often been carefully created with a lot of effort to ensure that it is playable and has manageable dynamics and the signal is above the noise of the medium.

In the days of Vinyl (we used to call them LP's) the noise was the real enemy and frankly has been the key driver of improvement ever since. Dynamics, frequency response etc. aren't even on the radar for most consumers. Move from LP (pops, ticks, scratches, noise) to cassette with Dolby (no pops or scratches but lousy random access and hiss) to CD's (no noise or scratches, usually) to MP3 download (nothing to break, even easier to get or steal and more music that you can ever listen to so it becomes wallpaper). The other improvements we care about don't even show on this scale. And the same dynamic limitations are still important; if you are listening on the subway, the ambient noise is the lower limit of your dynamics. Listening at work, too much dynamics on your headphone will annoy your cube-mates. Except for a few aging codgers most listening today is done in a completely artificial environment (headphones) of content that never mapped to a real space with a real audience in it. Our model of two speakers spaced in a room with a sound field between them may be passing into history.

Uncompressed dynamic are rare, to be enjoyed as a special experience and not a commercial reality.
 
DIY Vinyl....

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Might be fun...Information

This is just a quick aside...please do not allow this to derail the thread re op-amps.

Dan.
 
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