The AM Forum

I heard an old Navy sailor tell a story back when painting ships bright white was in vogue. The crew on his ship added in a little blue paint to give the white paint a brighter look. Maybe something to do with ultra-violet. Anyway, when the ships sailed by for review, the admiral commented that the crew from that ship did an extraordinarily fine job and deserved some extra leave.

Sometimes little subtle touches to our transmit audio can add up and can mean a distinct signal - your own "signature sound."  

I got an idea when listening to Tony Bennett's 1962 original version of, "I Left My Heart in San Francisco."   Listen closely and you will hear a beautiful real converted cathedral hall echo. No reverbs or electronic plates, just a large hall was used. (CBS 30th Street Studio)    Notice the sssss's. They have a trippy wisp to them. I thought I'd like to try this for the articulation frequencies between say, 3 KHz to 6 Khz or in that area.  I am not interested in the lower frequencies for this test.

In real world ham practice, I think Tony's highs echo should be backed off a bit to become almost invisible... but still a touch to give this effect. It would require a lot of experimentation, but could prove to be a rather cool, subtle effect to one's audio. I am told that certain newscasters, who know what makes their voices sound good, use this technique when having their audio mixed.

Listen to the recording below for sssss's at    :51 - :55        1:52 - 1:57 (Big)      :36 - :38     1:17 - 1:29 (Subtle)

https://www.youtube.com/watch?v=9UPdpzwyKgw

To do this effect, we would need an EQ acting as a bandpass filter (or high pass filter) to pass ~ 3KHz to 6 KHz thru to the echo effects box, then a mixer to combine the original mic audio with the new echo audio at the proper levels and polarity.

This could also be done in computer software with excellent control of the filter, levels and audio phase when combined again.

I'm ready for a new challenge. I haven't changed any audio settings, bandwidth or DSP audio settings on my 4-1000A AM rig in two weeks, so that project is finished. Happy as a clam with the current audio.  I'm looking for some new tricks or bells and whistles to play around with.   (Thanks Jeff/NBC for all your help)

Anyone ever try this or have thoughts on implementation techniques?  I'm in the info gathering mode right now and will probably need to buy some hardware to pull it off...


T

The English idiom for today is...

The thin edge of the wedge

Some minor change or development that instigates or foreshadows something much larger or more impactful. Typically used in reference to that which will lead to an unfortunate, undesirable, or catastrophic outcome.

I can't add effects of any kind to my audio as it would impact the brokered subcarriers on my signal. The quadrature modulated Portuguese Books On Tape channel and China Radio International hourly news channel (60Hz and 8.7kHz respectively) are precariously present on each transmission and both already complain of interruptions from fast break-in transmissions.

Gotta squeeze some cash out of this hobby or else why bother, right?

Tom I believe I know what you mean..I watch Jeopardy every evening on ch 8 here..Johnny Gilbert has it down pat..he's the announcer for the show and the beginning is probably what ur after..actually even when Alex Trebeck introduces the catagories there's a hint of that very subtle reverberation/concert hall effect..can't think of any other show that features this
                                Gud luk in recreating that "sound"  73 de DAVE WB1EAD

Couple things to note here --

Many decent quality reverb units are floating around these days for nearly nothing. They used to be a staple item in any live sound guy's rack, along with compressors, gates, equalizers, delays, and other devices. Then along came lower-cost digital mixing consoles, which integrated all of that inside the mixer.  Having done live sound since the '80s, I had at one time quite a rack(s) full of such gear, mostly higher end stuff by the time digital made it all obsolete. In fact, I still have a Yamaha SPX990 reverb, because I couldn't get enough for it on eBay to justify the hassle of the transaction. It was easier to sell the Lexicon and Eventide units...

Such units usually have pre and post eq, pre delay, plain delay, and reverberation eq/timbre adjustments, and of course a dry/wet mix control -- no need for the extra processing you describe, it should all be in the box. 

What you are hearing is a fairly strong, short, pre-delayed reverb. It is not an echo per se, which in sound guy terms, is a slapback, same sound, repeated, no lush tail or fadeoff -- like hello..lo..lo..lo  or my old time favorite, "Sunday Sunday Sunday at Martin US131 raceway, the Budweiser funny car nationals!"

In the Bennett recording, I am not sure that the effect is all reverb...it may be some distortion from either the record playback, or if it was a recording from the 40's, a specific distortion typical of the recording system back then.  Key thing to listen for is shh vs. sss sound-- shh, even just a little bit, is usually needle mistracking on the record. It is harder to tell after somebody runs it through all kinds of digital compression/bit rate reduction to put on youtube.

All that said, one other thing:  it is easy to overdo reverb. Some may remember 11m in the 70's...

Ed

Hi Dave,

I'll listen more closely next time Jeopardy is on.    I should have something working soon for the high frequencies.



Clark,  OK on your highly profitable pilot carriers. You'd be surprised how much data can be packed onto a compressed reverb tail.  Tony Bennett, a former Beatle, was a pioneer and used wet audio streams to overcome studio QRM. When he stopped singing, the stream was still talking. But, as you inferred, singing on the air is illegal, so he had to be quick.

T

Hi Ed,

Interesting on the potential distortion in Tony's echo highs. That was 1962, so they had decent audio then. I hear it but wasn't sure if that is simply the right sound or is it a bit of tearing.  

I am trying to find an effects unit, hopefully DSP, that will allow me to create a high pass or bandpass filter (built-in) before going into the echo.  I will have a second path for the regular mic audio that will need to be mixed for one output.  

From your experience, will any of the units you mention allow this, especially create a built-in filter?    


Plan:


Effects box:

Line Audio >  Bandpass filter for highs only>  EQ>  Echo > or EQ here  >>>mixer
---------------------------------------------------------------------------------------------   Limiter  > Transmitter
Mic audio > regular audio chain  >>>>>>>>>>>>>>>>>>>>>>>>>>>mixer    

T

Turns out that I already have a Behringer DSP 2024P effects processor - Virtulizer Pro.  It has a DSP filter in it. Plus many echo settings, cathedral, plate, etc.. I didn't even know it had a filter until I read the manual.

"Up to 7 adjustable parameters plus HI and LO EQ per effect."

So I just need to get a small mixer and we're all set to start experimenting with leaving my heart in San Francisco.

I'll post some on-air recordings once I get it working.

T


Filter/EQ effects

FILTER: Filters, in general, influence the frequency response of a signal. A low pass filter allows low frequencies to pass and suppresses high frequencies, while a high pass filter allows high frequencies to pass and suppresses low frequencies.

PARAMETRIC EQ: The parametric equalizer is the most highly-developed form of equalization. You can control the three parameters which define the so-called gauss equalizer curve: bandwidth, frequency and amplitude boosting or lowering.

GRAPHIC EQ: Eight filter bands are arranged next to each other for this graphic equalizer. In contrast to the parametric equalizer, frequency and bandwidth are pre-determined here.

You don’t need a mixer — it’s built in. Send line level audio into the box, select Internal Mix, dial up Intensity. 100% is all effect, 0% is all straight through/no effect. Put the box after most of your processing , but before the final limiter/clipper to prevent accidental overmod.

Keep in mind that Behringer is not top shelf gear, not even middle shelf. Results may be less than they could’ve been....

Ed

Thanks, Ed.


Yes, I am familiar with the 100% all effect, 0% straight thru, but didn't realize it was what I needed for this mixing application.

So the echo will be in the same phase as the original I assume, so no need for an echo path polarity switch.

If the Behringer works out well in concept, then I may be motivated to buy a more expensive effects unit like a Yamaha 2000 or Lexicon. At this point I have all I need to start.

Appreciate the dope, OM.

T

First Test -  I actually have it working, though I think I can improve it further with some bandpass filter changes, delay and echo choices.  

This is taken off the air into my SDR receiver.  The highs may seem a little hot, but after a pass thru the sky and the listener's receiver they are usually OK according to reports.

I will eventually find a mix that has just a subtle touch of echo in the highs, something like what you hear now at the "3% mix" setting in the recording.

I am cutting the lows by -16 DB and enhancing the highs by +16DB thru the Echo Bandpass filter. There is a lot more tailoring that can be done once I play around with the DSP filter settings.

Also remember that we are hearing no atmospheric noise or QRM to mask the faint highs echo. Normally the echo may have to be run hotter than this recording to come thru at all. We'll have to see.

*Another point... in normal speech, there are much less ssss's than heard on this test audio, so the echo will be activated less...

T

It needs a touch of vibrato. That, and re-insert the effect back into the left and right airchain channels in opposite phases to get an enhanced stereo separation effect. Ops with C-QUAM or Khan Independent Sideband receivers will marvel over your shack-filling audio. Well worth it.

Tom at setting 7 you can tell it's there no doubt but at 5 it's just there in the background..but you know I do like 7 as well so I'm thinking if it were my system I wud go with 6..and if you should decide on 5 well OK..more than 7 just might get ya "who's dat CBer" ?
Yah I have hoid a few over the years who may have started the commercials for Epping Dragway on Sundays..eventually you'll get it right if you already haven't..gud idea and Ed seems to know his way around audio as well  73 de DAVE WB1EAD

Dave / WZ5Q has also been experimenting with this same idea, but used on eSSB. (Hi-fi extended SSB)    I plan to try his Virtulizer settings, but on AM. 
He sent me this link:

http://www.wz5q.net/index/rack_data/dsp2024.htm


OK on your preferences, Dave. My last test will be to see how much average band conditions cover up the subtle sounds. For example, if the signal is full quieting, S9 +60, we would run the echo at 3% or less.   But what if the signal is buried in QRM and static?  No setting would work and bypass would be the right move.

Clark, I don't know what I would do without your keen suggestions.  Yes, shack filling audio is what we want. Based on your suggestion, I might look for three more echo units on eBay and run them all in cascade. 

It's like driving a car with skirts and a gangsta side-tilt-kit.  It may not do much, but sure looks great! 

T