SP-1a Speech Processor

Captain Kilowatt. What kind of radio do you run it on?

Thanks just curious what people are using. I would like to try a SP-1

Captain Kilowatt said:

He may not have it set up properly. There are two adjustments on the SP1-A and you need to set each one for best results. VR-1 adjusts the compression level while VR-2 adjusts the input sensitivity. Mine has a very noticeable punch to it yet it does not sound distorted or cause splatter but then again I set mine up watching an oscilloscope as well as listening to it off-air.

Click to expand...

My mentor had them in all of his AR3500 radios and they had the 100w option from the factory as well. He also had an RCI2950 with one.

This was around 1991 I think. When he would turn it on the lows dropped out a bit and the high's seemed to increase. The overall sound was a bit brighter and definitely much more clear and powerful sounding. It did sound a little strange but nothing you could put your finger on and if you did not know he had that installed you would never have known. This was pre-hifi and pre-eSSB so peoples sound on the radio was all over the place with no real standard sound. Most people would have thought it was a power mic with an electret mic cartridge.

When I say strange I just mean that in the back of your mind you could tell something was going on but it was not obvious enough to put your finger on. Kind of like when you gut tells you something about a photo or someone is off but you have no idea what it is. Just like how often you can tell that an instrument on a musical recording is "synthetic" or you think someone's voice has been over processed in the studio. Do not get me wrong they sound good the SP1-a but if you set it too conservative it makes little difference and if you overdo it people can tell it is not natural even if they have no clue why! It is the same with echo and delay if you use just enough to improve how your room sounds it is great but the second you can tell someone is running echo and delay you have gone too far and ruined things. Rednecks and trash do not apply echo, delay, and reverb as they should be used instead they overuse them to the point that they sound unnatural and distorted.

For the record guys if your radio room is harsh and dead sounding you use echo and delay to warm it up the same thing with reverb. You can make it sound as if your room is warm and alive even if it not. If you sound like a robot that is too much reverb!!! The delay feature is normally tied to echo function in 99% of the IC's that have that function. You have to turn echo on before you can add some delay. We really want to add some delay normally but in order to do that, you have to have echo on. So you use just enough echo to give you access to the delay function.

A lot of audio IC's that were designed for cassette players/recorders normally had at least two channels with separate gain stages, eq, noise reduction, auto level control, echo, and reverb. Often you had another eq that was for the different types of magnetic media.A lot of them had built-in switches to control other IC's and AGC functions etc....They are normally dirt cheap as well. If one was so inclined you could use the multiple channels for two different things. You could use the second channel as an extra gain stage. You could use it for compression. Lastly, you could use one channel for TX audio and the other for RX audio. Often one can shape almost any of the functions with either extra cap's or resistors in the signal path. A lot of these have built in filtering available and sometimes primitive cross-ovr like functions.

Do you know who made the processors for Clear Channel when they put them in the AR 3500? Another story but I run echo in my truck strictly a.m. and I love it I have that set just just-rite people think I'm out of base station.

Greetings!

If you ever used a SoundTracker ST radio from Cobra then you have a good idea as to how they can work.

Uses a Compandor, one side is a compressor - the other is an expander.

As the first part of it says, the ST's used a Compressor to your Mics audio while you transmit - it is a preset level and it was (still is) used in telephone handsets as a means to condense and narrow down your voice into a range of tone and power that digital processing and telephony networks could work with. Even your Cell-phone and Home Wireless phones are using this technology.

Expander side never really worked well for the ST units. Too many variables that affect their performance - from the external end. Hint: Real World...

Expandors are devices to re-expand or restore dynamic range - and using ST radios that expansion effect got in the way of echo mikes, loud background noises in the mics and general chit-chat from other non-ST radios.

It just made using ST expansion side - tedious - to use.

Now, if all you had were ST units on a noisy channel and everyone used it for purposes intended - they were admirably performing units - and well worth listening to and using.

The real world just gets in the way at times...

A better event would be to -tweak- your radios' limiter and mic amps sections to help improve the "punch" your voice has.

Some Mic elements are better in vocal and voice range reproduction than others and some older mic amplifiers in many of the older mics can sound better with an upgrade to the transistor amplifier in the handset - some older units use single FET (D104) but use a Salt-based crystal element no longer made. Can't do too much with those, but you're asking about installing a processor unit inside your radio...

Maybe you don't have to make it so complex, but then, anyone willing to use a speech processor must also have to "face the music" in using them. They may alter or add a color to your voice that you may not want - so you'll need to keep options open. (See Above...)

Many just switch to a power mic and figure it's done. That's fine if you want to bring in the dog snoring in the background while your cats' coughing up a hairball when you try to discuss the finer things in life with another power mike user that's tooling along about 45 MPH on a gravel road hauling chickens to the market with the windows down in their 64' Ford...

You get the idea...

There is another problem though, the mobile environment - you may have to twiddle with two levels - the Mics own internal amplifier setting and then there is the radios own mic gain level setting (if applicable) you can get distracted while texting just remember the same law can apply to using your radio too...

Base radio - lots of times it's a set it and forget it. Just remember if you have kids and a speech processor keyed up at the same time - the rest of us hear cartoons - Barney and children that are "learning how to cuss and act like mom and dad..." - in some ways it's called entertainment - others like the neighbors, get mad - possibly to the point they have to call CPS and your radio bleeds into their land line, computer speakers or their entertainment system, at least they have proof...

Ahh, Yes. The joys of CB radio ownership...

No wonder why there's Twitter....
Regards!
:+> Andy <+:

made by sam lewis and bob of bobs cb shop

That would mean the SP 1A is the same processor that was used back on the AR 3500 I think?

I believe it was, Bob at Bobs CB is supposed to be the guy to go to if you want one set up right.

Yes the current SP1-a is either identical or so much so that it does not matter. It is not anything exotic which is why they pull the blockhead maneuver and sand the markings off the IC. I guess they do not know how easy it is to insert an ic int a $17 Chinese tester and have it tell you the IC.

The only people that keep info from is the customer. If someone really wanted to copy it then it would not be difficult to do. Only incredible small minds do that sort of thing. I could make my own wrenches I had to do that in Middle School tool and die class but to be honest I would rather just go to the store and buy a tool! I know what PLL is used in a Cobra 148 but I am not churning out Cobra 148's in my basement!

I am glad they still make these, I am adding one to my list. Might try one on my Cobra 29.

yep that is were i bought mine. many moons ago. still sitting in the box

ShadeTreeMechanic said:

I am glad they still make these, I am adding one to my list. Might try one on my Cobra 29.

Click to expand...

I have one still in the box from 1998 or so. I bought it to install in my President Lincoln but I could not bring myself to punch a hole in it and none of the switches on the front are things I would want to give up. On top of that they are not a simple lever switch that is one or off they send a signal to a controller or the CPU so I would have to do a little bit of work even if I wanted to do that not as easy peasy as a light switch or a NB switch on a Cobra! So when I want to or need to have some processing I use an external unit. I am sure the lytic caps inside need to be changed since it has been sitting in the box never used for the last 19-20 years! LOL

If I can find the time I might put up a schematic for my favorite All Pass RF clipping/compression. My biggest problem is that I hate the scanner software that came with my printer. I have to have that software installed to use the scanner on the printer. The problem is that it is an obnoxious piece of software that wants to manage all your photo, video and other images. Even when you go into the registry and prevent it from starting up on startup it has a way of undoing that. It makes me believe it has a timer of sorts and after so many days it forces itself back on the startup list of software. The only way around it is to uninstall it. It is almost like Malware in how it seems to force the issue after some time. On top of that to be honest it is not a very intuitive piece of software and it is a resource hog.

I have all the 1970's/1980's documentation which is not much but it included a schematic so no worries about trying to decipher my chicken scratchings. I have thought about recapping it since it is prob. close to the same age as me. But it seems to be ok. If I recall it does not have a single electrolytic cap in it. It is all axial styroflex caps and I think 2 ceramic disc caps on the 9 volt power side, one ic which I think is just a generic audio ic and two puts and an on off switch. Oh I am pretty sure it has a 455mz crystal in it as well. It works great though and it is nice that it is external. I think it is 4 pin Yasue(sp) / Ten-Tec I think but obviously, you can wire it for whatever you like. So for not checking my spelling I have not slept in 4 days now and am too lazy to google it! LOL

Guys if you get the chance buy yourself a Ten=Tec 715 new or used. For any radio without processing it is killer. You will need to make up some custom adapters but that also allows you to use it on any radio you want from ancient tube type to modern Ham radio. Ten-Tec does not use the most common wiring on their 1/4" phono jack, In fact, it is backward compared to most.

I do like noise gates and downward expansion but sometimes the cost to get a unit with all of the above and a noise gate and downward expander just is not worth it.

Another gem the Demco Modulator Compressor. You do not want the one with just 2 knobs you want the one with 4 knobs. It hooks into the audio chain in about the middle of the chain so it works on tx audio and rx audio. On top of that it monitors the radio and adjust's itself with active feedback so it is never.It has Nuvistor tube a 8BQ5 and one more tube I think. Fairly rare but because it was designed from the word go to be hard-wired into a radio and has active AGC type function had is designed for rx and tx it is a rare bird when talking about compressors and gain stages for CB radio.

The problem is that these get snatched up almost instantly if they have a BIN price and if not they sell for insane amounts of money if they are a real auction.

You don't see many of these around. They must be pretty good as you say.