Here is what I found using both and comparing the two. The Sclockwood although made as an AM processor it can be used fine for FM also provided you are happy being in mono as FM works better in mono transmission and only a small change with the jumpers on board is needed for FM operation(disabling the pre-emphisis so flat response), not using the positive peaks control. The Cuthbert operates in stereo(two channel), unbalanced in and unbalanced out for stereo operation.
The Schlockwood has a mono balanced TRS output so to use with FM or AM with an unbalanced two channel input to the transmitter a small easy mod has to be done at the output with the wiring in the audio cable or on the circuit board of the Schlockwood to be compatible with the transmitter input i.e. Decade MS 100 or Procaster studio interface.
Using for FM and AM here's the difference in operation. They both achieve the desired result in different ways. The Cuthbert has 3 band compression and release for 3 frequency bands and once set it stays that way but if one song has the tonal balance different from another song(which it does) it doesn't work as good as the Schlockwood at keeping the bass treble and mid equal in each track. With the Schlockwood, the incoming audio is analyzed and reduction is applied where it is needed and not applied where it isn't and each track keeps the same bass treble and midrange the same regardless of the original audio a bit better than the Cuthbert so you sound more close to the commercial stations in that regard. That also keeps the on air volume more equal with each track and with the Cuthbert there still is some songs sounding louder than others and some sounding more bassy or trebly and this is controlled better with the Schlockwood. That doesn't mean the Cuthbert is bad, it does a good job but if you want more perfection and get closer to how a commercial station sounds I have to say the Shlockwood gets it closer. I have in the last two weeks with being on FM done an in depth comparison of the two. Hope I explained it right!
Advantages of the Cuthbert: works on common 12 VDC power supply, 2 channel output for stereo broadcast, works with any transmitter input and does a good job doing what it is supposed to do.
Disadvantages: can't adapt to input tonal imbalance of different tracks to keep each track sounding like the other as broadcast stations do.
Schlockwood advantages: keeps tonal frequencies pretty much the same with each track as compression is applied where needed through an AGC. 3 LEDs show the reduction and it is different for different tracks.
Disadvantages: needs a not as common 18 volt isolated switching power supply, can't work with battery. Needs a small mod to work with an unbalanced input like a Decade MS-100 or Procaster studio interface.
Conclusion, Cuthbert is good and an excellent choice for the more affordable price but the Schlockwood is better if you want to sound closer to the way commercial stations do. The Cuthbert is the choice if you want stereo broadcast capability and have a common 12 volt DC operation.
Very interesting post Mark, and for the most part your observations seem to ring true, but a couple things bother me. The first thing is that the comparisons of two processors designed primarily for AM processing but in this case your using them on a FM transmitter - So that right off kind of makes me tilt my head.
The FM Procaster is not really designed to expect a pre-proccesing -- not saying pre-proccesing won't improve the broadcast, but it's specifically designed for consumer grade inputs, like from a computer or mixer. The Procaster FM has it's own built in pre-emphasis and basic limiting, (and Stereo encoder if your using it), which is why you have to disable those features in your processor to use it on FM, otherwise your processor would be fighting what Procaster FM already does onboard.
Here is what I found using both and comparing the two. The Sclockwood although made as an AM processor it can be used fine for FM also provided you are happy being in mono as FM works better in mono transmission and only a small change with the jumpers on board is needed for FM operation(disabling the pre-emphisis so flat response), not using the positive peaks control.
I get your point here, but just to clarify; The way I understand it, FM doesn't sound better in mono, it's probably sounds incomplete in mono and not as good. But in mono the signal will travel farther, because all it's energy is going to a single channel rather than being split in two, so it will travel farther before it starts to distort or fade. Mono FM provides you better range, not sound quality.
The Cuthbert operates in stereo(two channel), unbalanced in and unbalanced out for stereo operation....
Just an observation, The Culbert is essentially two individual independent mono processors which happen to be inside a single box. That's why, as we've discussed before, you could easily use it to process two separate transmitters at the same time requiring different settings (like one FM and the other AM) with only a single Culbert (or Schlockwood or whatever).
Using for FM and AM here's the difference in operation. They both achieve the desired result in different ways. The Cuthbert has 3 band compression and release for 3 frequency bands and once set it stays that way but if one song has the tonal balance different from another song(which it does) it doesn't work as good as the Schlockwood at keeping the bass treble and mid equal in each track. With the Schlockwood, the incoming audio is analyzed and reduction is applied where it is needed and not applied where it isn't and each track keeps the same bass treble and midrange the same regardless of the original audio a bit better than the Cuthbert so you sound more close to the commercial stations in that regard. That also keeps the on air volume more equal with each track and with the Cuthbert there still is some songs sounding louder than others and some sounding more bassy or trebly and this is controlled better with the Schlockwood. That doesn't mean the Cuthbert is bad, it does a good job but if you want more perfection and get closer to how a commercial station sounds I have to say the Shlockwood gets it closer. I have in the last two weeks with being on FM done an in depth comparison of the two. Hope I explained it right!
Wasn't really sure how to take that so asked ChatGPT about your post and pasted what you said and it replied something interesting:
"Where the forum claim goes too far
“keeps bass treble and midrange the same regardless of the original audio”
That’s not physically possible without:
Dynamic EQ
Or multiband processing that actively reshapes tone
And even then, it’s limited
The Cuthbert is primarily a multi-band compressor, not an AGC-driven processor like the Schlockwood.
AGC Affects everything at once
Think of it like a hand on the volume knob.
Real-world analogy
Schlockwood = someone constantly adjusting the volume knob
Cuthbert = someone adjusting bass, mids, and treble knobs separately
Schlockwood = strong auto-volume control
Cuthbert = more controlled shaping, less auto-volume
A little more from ChatGpt, for what it's worth:
📡 Tie back to your forum guy’s claim
When he says:“Cuthbert doesn’t keep tonal balance the same”
What he’s really observing is:
👉 It’s not aggressively leveling everything like an AGC-heavy unit would
🎯 Bottom line
❌ Not correct: “Cuthbert has no AGC”
✅ More accurate:
“Cuthbert relies mainly on multi-band compression, with little or less aggressive AGC compared to the Schlockwood”
🧠 Simple version
Schlockwood = strong auto-volume control
Cuthbert = more controlled shaping, less auto-volume
Me: Ok, let's consider the same in regard to Schlockwood and Culbert processor for part 15 AM transmitters, like the Halmilton Rangemaster or Chez Procaster AM transmitters
Great—this is where the comparison really flips a bit, because Part 15 AM behaves very differently than FM.
Let’s anchor it to the typical transmitters you mentioned:
Hamilton Rangemaster
Chez Procaster AM Transmitter
📡 First: what AM needs (this is the key difference)
AM isn’t fighting high-frequency noise like FM. Instead, you’re dealing with:
Very limited bandwidth
Low modulation power
A need to squeeze loudness and intelligibility into a narrow signal
👉 So the priorities become:
Average modulation (loudness)
Consistency between program material
Controlled peaks (avoid overmodulation distortion)
🎛️ Now: how each processor behaves on AM
🔵 Schlockwood (AGC-heavy / adaptive)
👍 Where it shines on AM
This is actually where that AGC behavior becomes a big advantage:
Keeps average modulation consistently high
Brings up quieter material (very important on AM)
Reduces “dropouts” between songs or speech
👉 Result:
Louder perceived signal
Better coverage and intelligibility
More “radio-like” density
⚠️ Potential downsides
Can sound a bit “thick” or “compressed”
Less dynamic range
If pushed too hard → “muddy” sound on AM
🟢 Cuthbert (multi-band compression)
👍 Where it helps
Controls peaks in different frequency areas
Can shape tone (helpful for AM’s limited bandwidth)
More natural, open sound
⚠️ Where it falls short for AM
Doesn’t raise average level as aggressively
Quiet passages may stay too quiet
More variation between tracks
👉 Result:
Cleaner, but often not as loud or punchy
⚖️ The BIG reversal vs FM
This is the important takeaway:
Feature
FM (Procaster/Decade)
AM (Rangemaster/Chez)
AGC-heavy (Schlockwood)
⚠️ Can fight transmitter
✅ Very beneficial
Multi-band (Cuthbert)
✅ Plays nicely
⚠️ Less loudness consistency
@richpowers Much too many things here to comment on all or read it all in detail. But to correct you about a couple of things.....mono is better audio quality then stereo. Look on Decade's site with the specs of the MS-100 frequency response for stereo and mono and also note that mono has a cleaner signal(better signal to noise) and all receivers are more sensitive in mono. The Decade MS-100 I have and I think Artisan has is the mono version of it. You only get the 3D effect of stereo when positioned exactly in the right position between two speakers or headphones. Not in the exact right position and you don't hear it anyway.
Search AI with...would broadcasting in mono increase coverage with better signal to noise and audio?
I would ask Sean Cuthbert about your idea that you can drive 2 transmitters with his one processor and your assumption that it is two mono processors separately in one.
I don't think so but see what he says and I will stand corrected if wrong.
As for the processing the Procaster AM gives you it is very basic and that's why it has the jumper to bypass for a better external processor. It is just that it is not necessary
As I said about the Schlockwood it works different than the Cuthbert in that compression(reduction) is applied on the go as needed with the 3 frequency bands keeping the frequency balance with the mid bass and treble with multiple tracks and the lights show this and it differs with each track while the Cuthbert just stays the way you set it. The AGC is jumper selectable so you can see how it works with out it.
Finally the Cuthbert is not made for just AM....it is for both FM and AM + is also for DJs and other audio systems. The Schlockwood can work fine with FM also by disabling the pre-emphisis. You just have mono but since I broadcast in mono it is perfect. Half of all my playlist is in mono anyways. Heck, I grew up with a record player with one speaker and listening to a radio with one speaker. I hate headphones.
I just gave my review of what I experience between the two in actual operation and how they both operate.
https://www.manualslib.com/manual/1595156/Schlockwood-Sw200.html
Specs for Decade MS-100
- Modulation: FM, 75 kHz deviation
- Frequency selection: 88.1 - 107.5 MHz
- RF power: 250 µV/m@3m (FCC Part 15 and IC RSS-210), 100 μV/m@30m (IC BETS-1), 1 mW (IC RSS-123)
- Load impedance (UHF connector): 50 Ω
- Spurious rejection: 40 dB min.
- Frequency response: 20 - 20 kHz (mono models), 20 - 15 kHz (stereo model)
- Harmonic distortion: 0.3% max.
- Signal-to-noise ratio: 70 dB min.
- Stereo separation: 35 dB min., 40 dB typ.
- Input sensitivity / impedance: -15 dBm to +22 dBm / 5 kΩ (mono unbal.), -13 dBm to +22 dBm / 10 kΩ (stereo unbal.), -10 dBm to + 22 dBm / 600 Ω (bal.), -60 dBm to 0 dBm / 950 Ω (mic.)
- Power supply: 110/16 VAC @ 300mA
- Dimensions: 6.3" W x 10.5" D x 1.75" H
- Weight: 5 lb.
@richpowers Much too many things here to comment on all or read it all in detail. But to correct you about a couple of things.....mono is better audio quality then stereo. that mono has a cleaner signal(better signal to noise) and all receivers are more sensitive in mono.
Exactly, but that's not a correction, it's just another way of saying the same thing... When you broadcast FM in mono, particularly in part 15 limits, all your allowable signal strength is going to only one channel, thus it's stronger, and that is why the better signal to noise ratio is achieved. But it loses it's other channel entirely and loses all stereo effects, so broadcasting in FM mono is not going to sound as good as broadcasting in FM stereo will, but it will provide cleaner reception for a greater range. But no, I disagree, an FM stereo broadcast will sound better as long as your in range than a mono one would. - Since range is so often a priority then that is what makes FM mono preferable, it provides a cleaner signal in regard to distance only
I would ask Sean Cuthbert about your idea that you can drive 2 transmitters with his one processor and your assumption that it is two mono processors separately in one.
Ask, but we've already cleared that up here a month or so ago which Artisian also confirmed as accurate
Oh... Your using the Decade? I thought you were using the new FM Procaster model (not that it makes any difference in regard to my points).
Perhaps not the case with the Culbert, but thee Schlockwood was definitely designed specifically for AM, and it's capabilities of pushing the modulation to the max.
Incidentally, I think your review was excellent - wasn't trying to say otherwise, was only expressing what thoughts came to my mond
Oh, and you got a good point... Most portable FM receivers only have a single speaker anyway. Kind of makes the mono vs stereo FM a moot point in that respect I guess, but on a car stereo a stereo broadcast would certainly sound better than a mono one - wouldn't you agree?
I don't think I was involved at all with the discussion surrounding the Cuthbert and Schlockwood. You may be confusing me with someone else.
FM stereo doesn't give you anything if your music sources are mostly mono, which is the case with Mark's format (50s and 60s) and mine (basically everything 1930 and prior).
And most stereo receivers automatically switch to mono when the signal level drops below a certain threshold, as they're more sensitive with mono. Given the power with Part 15 FM and BETS-1 (virtually non-existent), you'd have to have your receiver pretty close to the transmitting antenna to get any benefits from stereo.
@artisan-radio No, not that, but that a single 2 channel processor can drive two different transmitters at the same time, even with different programming sources. Left channel to one transmitter and right channel to the other transmitter.
We talked here last month or so.
@artisan-radio I mentioned you in my conversation with Rich when talking about mono broadcasting and said my Decade's are the mono models and I said I think Artisan's are too.
I have contacted Sean Cuthbert about what Rich is saying that his stereo processor can be used as as two separate mono channels.....two mono audio sources(computers) and drive two transmitters broadcasting the same or different programs in mono from each channel. Two stations from the one processor.
I await his answer. I didn't think it could work that way and if he says it is possible I will stand corrected. I will post the answer I get.
OK I got the reply to this. I stand corrected as this was my answer. But technically doesn't mean practically...
|
"Technically It can be done as the compressor has 6 separate compressors.
3 on the left and 3 on the right. So the right compression will not interfere with the left." But that wouldn't be practical as the controls control the compression and release and EQ together(both channels) and what if you actually ran two stations, one AM and one FM but for each the settings had to be different? You don't have two sets of controls for separate adjustment of the left and right compressors, release and EQ Possible but not practical, and I don't think this has ever been tried with one processor operating 2 stations simultaneously(to my knowledge) and I don't think it will. But since it technically could work with the Cuthbert so I stand corrected. |
But that wouldn't be practical as the controls control the compression and release and EQ together(both channels... You don't have two sets of controls for separate adjustment of the left and right compressors, release and EQ..
Uh... Yeah I think you do too, I've never known a compressor that didn't. Attack and release controls are always separate. Correct me if I'm wrong,
Possible but not practical, and I don't think this has ever been tried with one processor operating 2 stations simultaneously.
Nothing impractical about it, a stereo compressor or limiter is two individual mono units in a single box. Though I don't actually know anyone who's used it for two transmitters, I know its often used one channel to the transmitter and the second channel to the online stream, or to the studio monitors (like used to do it) Im pretty sure it's a common practice. It wasn't something I dreamed up myself.
The Aphex Compellor model I used was a 301 model, which was simply a 1 channel mono version of their stereo Compellor model, so naturally it could only output a single stream, whereas my Aphex Dominator was a stereo unit ( as most any brands usually are) thus providing two independent outputs. But at it core, they are always just 2 mono units in a single box.
@richpowers You have the front controls, EQ bass mid and treble and release bass mid and treble and one control for the compression that controls both 3 bands(both channels) with the one control.
The tone controls just control the drive and output of the compressors but the two 3 band compressors are controlled with ONE control and the tone controls the both 3 bands simultaniously also.
It was made for stereo. If what you say is true you would need 2 sets of controls....bass mid and treble, two sets of release controls for bass mid and treble and two controls for compression, for having one 3 band compression different from the other for the two stations. If that wouldn't matter and the same setting for both stations would be satisfactory you may get away with it. A project for you to try with yours and then you can be a first to try this and report how it works. You can put the theory to the test.