Continuing covering suitable ‘fx’ which can help with your output tonality and clarity -
a) Compressor - in principle, yes, but use with care. As a DRC method (Dynamic Range Control) style method, it works well when correctly adjusted in it’s attack, decay and sustained and level of compression, and makeup gain. A blended us of dynamic audio compression on say your actual voice frequency bands which have less emphasis to the degree that your audio out sounds weak and simple Parametric EQ to focus emphasis on your main voice characteristic frequencies is a good combo to start with. Potentially, with good mid-range emphasis and as full a natural reproduction of your particular ‘voice’ frequencies range within the accepted telephony range is your goal. It’s ok to sound ‘talk radio’ broadcast punchy where it benefits, within reason, but remember your QSO partner(s) are listening to a reproduction akin to the AM tonal response of a classic Roberts AM receiver speaker response profile. So if you can get your audio to reproduce well on that kind of speaker amp equivalence, you’re in the ball park comfortably.
b) Reverb - If mention i mention, reverb fx, you start having CB flashback nightmares about demented Echo mic users, that’s forgivable - no, i’m talking about positive use of reverb.
You can take an echo/reverb fx, reduce the repeat rate to zero, and adjust the rest of the settings to create a simple ‘double voice’ effect that when balanced wet to dry properly, gives you vocal singer’s recorded ‘airy feel’ to your audio which can make it a bit easier to listen to. It definately adds some emphasis and when set with a suitably short ‘tail’ (‘tail’ being the time the single reverb effect hangs on after you stop talking or take quiet breath pauses). So adjust it consideration of the main audio limits (you will go back and forth many times getting it spot on, comparing it’s added effect to what you’ve already done).
c) Parametric EQ - this is the big booted leader of your SP pack of effects. Get this side spot on, use the other two items for emphasis and punch.
A good Parametric has multiple bands (at least two, three is what i call a real minimum). Each band has, like with a graphic EQ, an associated freq range - but unlike a Graphic EQ’s basic boost/attenuate continous adjust setting, you’ll have a more moderate gain to attenuation range per band but you also have a band window adjustment (adjustable BPF) where you can move the center frequency of the band range. So by listening to your output, you can (per band) tweak this per-band window so the rolloff favours the more naturally emphasis of your actual input (mic) within the design response of the mic’s driver. Adjust this for each band (simple good ParaEQ’s have a basic Bass, Mid, and HF adjusts with a wider window adjust). The third major control alters the actual width of the window, so even a three band ParaEQ can make a useful tonal make up on a mic that maybe isn’t so great with your voice. It can, with sane adjustment, make you sound less over bright on an electret insert and even give the tone a more dynamic insert tone.
Moving onto more ‘modelling amp’ type useful FX, we start with -
Single/Humbacker modelling - designed to make a Humbacker type pickup sound more like a single coil pickup and the other makes single pickup guitar sound (example, you have two or three single pickups on most non-bass Fender guitars) sound more like the fuller less noisy Humbacker pickup tone. This, used with caution and care, can be a subtle but effective way of rounding out how full your mic audio sounds especially where it’s more where a non-reverb semi-doubling/harmonised blend is all you need to add emphasis to your spoken audio.
Gates - these allow you to set a pre fx lower threshold where if your input audio drops below the adjustment threshold, no audio passes into the effect chain. Some amp/guitar modelling ‘pedals’ or stacks give a you a post fx gate, so you can adjust to ensure only audio within a higher or lower threshold ever leaves the ‘device’, so combined with a low mic gain on the radio, means there’s a margin where the SNR at the mic amp isn’t into the noise floor, but the amp’s internal noise isn’t notably adding badly to the overall resulting received SNR.
But you must ensure your quieter audio, spoken audio, sits far enough above the noise floor and still have (uncompressed) a natural softness of softly spoken audio. Likewise, you need to ensure the peak–to-peak range sits comfortably under 0dB, with room to spare (headroom) to which i suggest a minimum of -3dB below digital peak (0dB) or better still, -6dB relative.
In digital voice terms, you are aiming for a) getting the most effective clear non-metallic and not ringing and non-clipping demodulated audio as heard. Metallic sounding audio is the DV equivalent to dropping below the threshold, where if you could see the received SQ, you are moving all over the place SQ wise, of stable SQ. Again, as with FM (and notably given DV on VHF/UHF is an fsk/fm hybrid - which depends on the actual DV mode), you only need to be comfortably avoid a threshold and steady in SQ to be the DV equivalent of ‘fully quietened’. Any substantial over-level on sig above that gives rapidly decreasing gains in non-existent added R in RST.
So a good jumping in point is to optimise your settings/setup (AF and RF) for analogue FM over a moderate distance where you are still ‘above threshold’ and not getting lost in the noise. Then alter it slightly, but carefully, to get a similar level of balance in DV but with an emphasis on being free of ‘ringing’ and ‘metallic’ in the resolved audio. Parrot/Echo test on a repeater or hotspot is good for this, hotspot for general eval and a nearby repeater, preferably one you’re borderline accesible to, and repeat your DV echo test. If you get mostly a ring and metallic free echo back, you’ve in the threshold - there’s really no reason, unless you’re on the fringes of a hotspot coverage, why you would sanely ever get an Echo back that’s got a ringing or metallic or both tone.
You’re definately trying to avoid Radio Luxemborg ‘fady fady’ AM effect where your audio is sounding like’s jumping between a bad day on 80m and at the other extreme, sounding like CB’er using max rig mic gain and the full kick of their power mic. After all, ou’re setting up speech processing, not trying to hit the crowd at the back of an arena on a PA system.
At the end of the day, you want your audio level as heard modulated, to be above the noise threshold and below clipping/distortion etc. So that could mean a set of adjustments where your quiet audio (even at extremes of distance and low sig quality) is heard at least a few dB above ‘the noise’ (in FM terms) and inside of threshold without being overdriven. Remember, with FM, you’re gains in ‘punch and clarity’ become very much a reducing loss of gains once you are comfortably ‘above the threshold’ to be ‘fully quietened’. In fact, a good report with tell you if you are hitting the ‘fully quietened’ level in FM use, as a lot of the other traditional descriptions are CW specfic (the T in RST), so a high R in RST is where you are fully quietened FM noise wise and clear to a natual conversation level. Likewise, you don’t need a needle banging S meter level (as heard) on FM usage - if your sig as heard remains steady (S meter reading) enough to keep you in the fully quietened range, your ‘S’ in RST report is good.
I aim, typically, to be able to leave the radio’s mic gain at unity and use makeup gain on my external kit and set up my externals setup to keep audio fed to mic socket comfortably within the correct mV range that prevents the FM limiter (analogue) from tripping and likewise creates pure digital silence level in where i’m not talking, natural pause and cautionary pre-response initial pause and is comfortably short of clipping to the point that if i knock the mic over or drop it, the resulting thump gets muted by the external audio setup’s limiters.
If you’re not using a base mic, on your indoor setup, you could always try any of the above ‘SP’ type methods, employing each to a different mic - say the equiv of a common Shure vocal/speech mic and a semi or highly directional electret. Adjust each, in how the level inputs to the chain and make adjustments to each version, find a balance if you have only one set of stuff to work with and use a two-channel mono mixer with attenuated master output (or line level if your audio kit can accept it), but ultimately, no matter what, you want to be feeding lowish mV level range into the rig’s mic input.
That’s partly why i utilise guitar/instrument stuff for ParaEq, compression etc, as the passed audio to each unit or module is kept within a HI-Z input range which, if the output was designed to go into a Hi-Z input of an instrument AMP or PA, is pretty ■■■■ close to what you want to feed a mic input on your rig. If it’s slightly too high, crack back the o/p level on the final stage of the external audio chain a touch and you’ll be comfortable.
It’s how, on base operations, i get a punchy but clear near-broadcast sounding spoken audio received, by taking audio mastering techniques used in pro audio and broadcasting and applying them within the realms of affordable audio kit. And given how modelling kit is rapidly making single effect guitar pedals unattractive and unnecessarily a liability for leisure musicians, you’ll find there’s a lot of old-school guitar pedals out there to exploit and modify to build your SP chain with. I happened to have a spare Digitech and a PC/Midi controllable more complex unit left over (i favour the Digitech for instrument use, hence owning a few duplicates) so they tailored my choices.
However, if you want a more focused example ‘off the shelf’, there is a multi-effect modelling unit by Digitech that’s specifically tailored to Vocal/Speech use, but typically (where you see them listed), they are boarding on low-mid priced ParaEQ SP’s sold to the ham radio market, so you’d see value in being able to repurpose an instrument version instead - but i would avoid a Bass focused pedal use, as it’ll be good at lower AF, but very limited in effect on the MF/HF unless it’s tailored for jazz bass use where the strung range of JG’s is a crossover between mid/high P Bass tunings and lower EG tunings.
Assuming that’s all way to much effort, there is an old trick that’s dirt cheap - take your mic level into a classic tape recorder with a good AGC auto record level. Then attenuated the DIN line out or the earphone socket level to mic input level range. If it passes a record monitor level, just defeat the write-protect lever and use the monitor’s amplified range for a crude pre-amp. That’s how i used to get around record level issues on cassette based computer storage systems, using a crossover between the in and out of the computers using the aux/Din and main sockets of a cassette deck created an effective preamp that made cloning code between computers easy and painless.
Remember, there’s little in radio that’s not solvable by ingenuity and a bit of lateral thinking - just remember to draw a line between sanity and TA restrictions.