BBC Dip

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Please, can you two that has come to a conlusion in short summarize this? Please :wave2:

I have tried doing that several times already in this thread and nobody has yet tendered any other rational argument to dispute it. It does not mean my conclusion is "correct", but it is at least supported by reasoned argument and appropriate references.

"“Today’s scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality. ”
― Nikola Tesla "

My comments make specific reference to the attempt to unite subjective (experimental) well-established findings with objective measures.
 
Unusual ear response?

Having read through this interesting thread, I was struck in particular by two comments. The first that the BBC dip (real or phantom as the case may be) was used to prevent harshness, especially in symphonic music; the second that the human ear canal has a resonance at 3.5 k.

Harsh violins and flutes in some symphonic recordings have been bothering me for years. Have used a DEQ 24/96 to try and fix the problem, but was never entirely happy with results. Several months ago I added a DDRC 22D, with Dirac 1. Very happy with the overall improvement, but even on some good recordings the fiddles can be overwhelming when they are high and loud.

I measured the Dirac-corrected response with a decent SPL meter, and found it was reasonably flat in the treble. Then, using a recording of 28 calibrated sine waves a semitone apart (1397 Hz - 7902 Hz), I simply listened to the playback through Dirac and noted the frequencies which bothered my ears, despite the SPL meter not matching my subjective impression.

These began suddenly at 2093 Hz and continued to 2637 Hz, then started to sound too loud again at 4186 Hz - 4435 Hz (i.e. at the first partial).

Having corrected the Dirac target curve to take into account what I assume are anomalies in my hearing, I can now listen to the Bernstein recordings of Brahms symphonies (Vienna - DG) without cringing. Getting on in years, and cannot hear much above 8k, but can still hear the result of a .5 dB change in gain.

I'm new here - any comments or suggestions would be welcome.
 
I came across this on another forum;

"“Today’s scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality. ”
― Nikola Tesla "

.... and then those theories are confirmed or discounted after experimental evidence.

Mathematics allows humans to jump ahead, far past the results of consecutive experiments. It allows scientists to contruct experiments that otherwise would not have been apparent were worthwhile or even conceivable.

Tesla was an intelligent inventor looking to make money from patents. It's not a surprise he was a hater of scientific method. He probably found it too high-brow, exclusive and snobby. That's why he is revered by science-hating folks all around the world who prefer conspiracy theory and very very broken logic (i.e. bias-led theory).
 
Which in many cases is no doubt true, but Tesla had a fundamental point, and it wasn't necessarily divorced from scientific method. Just a reminder that scientific method starts with the basics; it's very easy to focus so much on increasingly elaborate theory (be it mathematical or any other) that you overlook the obvious staring you in the face. A trifle ironic in his case, but true enough. I'm sure we've all run into various instances / degrees of that, which can be as ridiculous as stripping down a TV remote looking for dodgy contacts etc. while failing to notice that the TV isn't plugged in.
 
https://www.diyaudio.com/forums/multi-way/83755-meant-bbc-rise-8.html#post972549

Remember that this was a "near"-field MONO loudspeaker for monitoring..

It's been reported that his son, Gundry Jr. (Keith), thought it was simply a defect of listening off-axis from the speaker: but they didn't do try to do that with MONO monitoring - they tried to get it aimed on axis (both horizontal and vertical) to the person doing the monitoring. In fact, they didn't always get this correct vertically - and Harwood (a bit later in the BBC's history) actually adjusted these MONO monitor(s) vertically (dropping them a bit lower from the ceiling) to achieve a response that was a bit more "flat" (though there was still a narrow-band "dip" in the treble). Harwood actually had a few papers on this topic.

Note that this wasn't the only "dip".

I had some internal pdf's from BBC at one point on this subject that showed several alterations in freq. response.

Classically (internally at that early point) the treble "dip" isn't really the "BBC dip" - that was later.

Rather it was a modest "tilt" from 100 Hz downward to about 6 kHz (or higher), and was not unlike the "far"-field stereo Power Response that Toole and Olive favor.

..and remember: that "tilt" BBC dip was "NEAR"-FIELD, with a more directional speaker (in MONO).
 
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.... and then those theories are confirmed or discounted after experimental evidence.


..Tesla was an intelligent inventor looking to make money from patents. It's not a surprise he was a hater of scientific method. He probably found it too high-brow, exclusive and snobby..


Except of course that many of those theories have never had experimental evidence. They are still just theories.

You should really read-up (or watch) a good biography on Tesla, what you've written about him (other than being an intelligent inventor) is just flat-out wrong. :eek:
 
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