Post by exbostonradiodj on Apr 23, 2013 0:05:23 GMT -6
That's EXACTLY why Bob Orban designed the 8100 with the multiplexer and processor in the same unit...to ensure the multiplexer wouln't affect the processing design the 8000 was known for during the years of the loudness wars in the top 20 major markets. Of course it didn't take long for engineers and companies to hack, modify, and super compress the audio resulting in a totally 'squashed' signal in most larger markets. Dynamics meant nothing..standing out on an over crowded dial to capture the listener's attention....and (hopefully)retain their attention (playing the numbers game) long enough for the stinger/stager/free money song/jock vo to 'hook 'em with what the give away of the hour was....yes sir...I sure do miss those days NOT!!! From an engineering standpoint, you just designed an improved 8000 on a perf board. VERY, VERY impressive homebrew project
That's EXACTLY why Bob Orban designed the 8100 with the multiplexer and processor in the same unit...to ensure the multiplexer wouln't affect the processing design the 8000 was known for during the years of the loudness wars in the top 20 major markets. Of course it didn't take long for engineers and companies to hack, modify, and super compress the audio resulting in a totally 'squashed' signal in most larger markets. Dynamics meant nothing..standing out on an over crowded dial to capture the listener's attention....and (hopefully)retain their attention (playing the numbers game) long enough for the stinger/stager/free money song/jock vo to 'hook 'em with what the give away of the hour was....yes sir...I sure do miss those days NOT!!! From an engineering standpoint, you just designed an improved 8000 on a perf board. VERY, VERY impressive homebrew project
I would not say I improved on the design by any means. If anything I just took a lot of notes by reverse engineering the 8000 by studying the schematic and figuring out ways to simplify the circuit to make it less complex while still achieving the same goals. The 8000 is still a complex beast given that it is not only an audio processor but also a MPX generator. Even the box the thing is built in was over engineered to reduce any possible RF feedback. OTOH I will take credit for possibly being the first that I know of to build a proper FM audio processor for pirate/part 15 operation using the minimal parts feasible while still getting the full job done
It does seem the newer audio processors were designed with loudness in mind. Especially the digital ones. Back when analog was king, people respected dynamics and the loudness wars haven't begun yet. The use of audio processing was limited to simply manipulating the programme content so that it could not over modulate a transmitter, and as a nice side effect bring up audio loudness slightly. Of course it didn't take long until engineers at stations tried to abuse that later part to get more punch and pinch the audio content until it looked like a brick wall on a modulation monitor scope.
Loudness can sound cool when it's done properly but the sad part is some people can't hear over processed distortion if it smacks them in the face and those tend to be the types that licensed stations hire, OR they were painted into a corner by their station manager to do so even though they know better.
Either way thanks for the compliment This was one of the funnest and most educational projects I have ever built.
Post by jessewillem on Apr 23, 2013 11:06:35 GMT -6
You can set digital processors a bit less loud too ;-)
With my piece of software is just as simple as reducing the drive to the multiband compressor and limiter and the final clipper :-) In most other processors, it will probably be the same. Also making the time constants slower will make things sound less squashed.
And I agree with Kage about that brickwall sound. It's lifeless and annoying when I'm listening for some time to these kind of stations. Sadly most stations in the Netherlands are processed that way...
My preference goes to being the middle man of it. Not to be too soft, but not being loud all the time. Still modulating towards the 100%, but not letting it stick there.
That's EXACTLY why Bob Orban designed the 8100 with the multiplexer and processor in the same unit...to ensure the multiplexer wouln't affect the processing design the 8000 was known for during the years of the loudness wars in the top 20 major markets. Of course it didn't take long for engineers and companies to hack, modify, and super compress the audio resulting in a totally 'squashed' signal in most larger markets. Dynamics meant nothing..standing out on an over crowded dial to capture the listener's attention....and (hopefully)retain their attention (playing the numbers game) long enough for the stinger/stager/free money song/jock vo to 'hook 'em with what the give away of the hour was....yes sir...I sure do miss those days NOT!!! From an engineering standpoint, you just designed an improved 8000 on a perf board. VERY, VERY impressive homebrew project
I would not say I improved on the design by any means. If anything I just took a lot of notes by reverse engineering the 8000 by studying the schematic and figuring out ways to simplify the circuit to make it less complex while still achieving the same goals. The 8000 is still a complex beast given that it is not only an audio processor but also a MPX generator. Even the box the thing is built in was over engineered to reduce any possible RF feedback. OTOH I will take credit for possibly being the first that I know of to build a proper FM audio processor for pirate/part 15 operation using the minimal parts feasible while still getting the full job done
It does seem the newer audio processors were designed with loudness in mind. Especially the digital ones. Back when analog was king, people respected dynamics and the loudness wars haven't begun yet. The use of audio processing was limited to simply manipulating the programme content so that it could not over modulate a transmitter, and as a nice side effect bring up audio loudness slightly. Of course it didn't take long until engineers at stations tried to abuse that later part to get more punch and pinch the audio content until it looked like a brick wall on a modulation monitor scope.
Loudness can sound cool when it's done properly but the sad part is some people can't hear over processed distortion if it smacks them in the face and those tend to be the types that licensed stations hire, OR they were painted into a corner by their station manager to do so even though they know better.
Either way thanks for the compliment This was one of the funnest and most educational projects I have ever built.
pal I made your plan in pcb so I can fix opium shall see whether it has the wrong Thanksgiving and if there are errors in the isolates the diorthosi email musicmania1066@gmail.com
After playing around with the old BA1404 based FM Ramsey transmitter again I forgot how nasty those high frequencies can sound on a cheap transmitter. Figured I would whip together a 6 pole 15kHz low pass filter. I did this with 3 JRC 4558 8 pin opamps on a perfboard and was amazed at the results. Not the sharpest cutoff ever but it protected the 19kHz pilot a lot more than without, and really cleaned up the 38kHz stereo subchannel.
I had one of those ah-hah moments realizing just how important it is to filter the audio that goes into these smaller FM transmitters. I'm sure an 8 pole filter would have even been better and there is no reason I can't add another chip to do just that. I only have so many opamps laying in my part box though, so I plan on using another one to notch out anything at 19kHz to completely protect the pilot.
I will post schematics soon when I get it all put together. The question is banging around in my head though how many other pirates here use a quality audio filter ahead of their FM transmitters input? What kind at that? Without the filter I'd imagine audio would sound awful on those chinese transmitters, MP3 transmitters, and most kits like the Ramsey FM10.
If you ever wonder how good your transmitter sounds there is a quick way to do it, just plug in a sine/square wave generator and sweep the thing from 10hz to 100kHz. There is software to generate those waveforms for you if you don't have the real deal. Do so with either the left/right or both channels and listen to your audio output on a good radio. El-Cheapo transmitters will have nasty harmonics when getting above 8-10kHz audio, and will even let things above 15kHz get into the audio even allowing audio to get into your stereo pilot and stereo subchannel! Squarewaves are the real test. If you're going to hear harmonics or aliasing this type of waveform will bring out the beast. A quality transmitter and/or audio processor will not have those issues and will not pass anything above 15kHz (especially harmonic content in music, like that produced by kick drums and cymbal crashes).
When I swept the Ramsey FM10 with a square wave the sounds I heard on air were sickening. Most frequencies killed the pilot even with very low modulation, made odd synthesized sounds pop out, multiple tones that didn't even exist, and stuff that sounded like it came from a horror movie. After running through the 6 pole filter? Almost flawless like a pro transmitter, nice clean square wave sound w/o distorting the audio.
OMG.. language barrier aside that is awesome! Thanks. If you use the design please just give credit where due. Will be very interesting to see others build this if the PCB was easily available and see what the results are.
Post by wilmerjavier on Feb 15, 2021 16:06:35 GMT -6
Receive a cordial greeting ... I have doubts in the references of the fets. not clearly appreciated. if you are so kind to answer what are the references of the fets, thank you very much ... thank...
Mierda, ¿alguna vez se preguntó qué tan mal suena su procesador de audio FM o su configuración sin ningún tipo de procesamiento?
Esta es LA canción de prueba para probar ...
Heart - Alone
Esta canción casi pasa mi procesador de transmisión que hice, pero realmente comenzó a morir por la sibilancia de su voz. el audio y realmente presionando el compresor de banda de paso haciendo agujeros en el audio en los peores pasajes de la canción.
Aún así, los efectos no se notaron demasiado cuando se ejecutó la ganancia de entrada a la par con la entrada de nivel de línea, en otras palabras, ¡sin presionar el primer limitador al límite!
Incluso más allá del primer nivel de las etapas del limitador, todavía sonaba bien, pero realmente podía escuchar partes donde las voces cristalinas perforaban agujeros en el resto del audio, pero les recuerdo que escucho cosas que al 90% de mis oyentes no les importan, así que esto puede sea un punto mudo.
Lo curioso de esta canción específica que menciono es que es bien conocida como una canción de prueba para las emisoras de FM. Muchas personas que juegan con el procesamiento de transmisión usan esta canción como una canción. O suena bien a través del procesador o suena horrible.
Ahora, para aquellos de ustedes que no usan un procesador de audio o cualquier tipo de ayuda para limitar el audio, deberían poder tocar esta canción fácilmente y se desatará el infierno. ¡Intentalo!
Me sorprendió la primera vez que escuché esta vieja canción y me di cuenta de lo mala que podía ser. Bueno, aprendí una lección rápida sobre la diferencia entre el audio dinámico con calidad de CD con énfasis en las voces FEMENINAS en comparación con cualquier otra cosa normal. Santa mierda hablar sobre la diferencia entre distorsión y bombeo en comparación con composiciones niveladoras y reguladas.
Tengo mucha curiosidad por que todos prueben esta canción en su configuración y se pongan en contacto conmigo. No te sientas mal si mata tu audio. Incluso los mejores procesadores de audio más caros fallan un poco en esta canción de Heart.
Por favor, vuelve a llamarme cuando hayas terminado de llorar.
La conclusión final es que lo analógico nunca rivalizará con el filtrado o la compresión digital en teoría, sin embargo, aquí estoy escuchando mi propia caja a través de un transmisor FM en una carga ficticia y suena mejor usando mi caja que usando el software de procesamiento de transmisión de software digital de demostración. .
La versión de software de esto puede manejar los puntos de corte mejor que mi caja y matar por completo todo en algún punto específico, pero el digital en sí mismo causa desagradables armónicos de aliasing, y en experimentos veraces que usan software de demostración como breakaway en comparación con mi caja, mi configuración puede no dar el mayor volumen, pero seguro que no cambia drásticamente la fuente de audio.