TC Electronic RH450 discussion - Tweaking the Preamp

[BassmanPaul]

I assume by 'test pilot debacle', you mean 'I wasn't chose and hence offended'

I've been thinking on this Ken since I replied to you. Thing is how do I get to try one of these things? I have one music store in my immediate area. Until recently I hadn't seen a Mark Bass product. They are supposed to be coming out of the woodwork and are distributed from Mississagua. That's the next attached city west of Toronto. I've seen one in my local store. Never even seen the Rebelhead. I believe that had I been selected for the test I would have bought the amp.

I'll continue to follow this thread and your posts. I've come to value your opinion since joining TB.

Paul

 

[OhulahanBass]

Taking water breaks from yard work and checking in on my favorite thread

Ken or another wise TBer,

What is Q. Is it the width/band of the boost/cut? Typically I think of Q referring to peak but don't understand why you would want a peak/level control when turning the boost knob controls your peak/level.

 

[engedi1]

Q is indeed the width of the boost/cut. For example, a 1 octave Q at 800 htz, will boost/cut frequencies within an octave of 8000 htz. The RH450 is semiparametric, which means you can adjust the frequency, but not the Q, which is very wide,2.1 octave according to kJUNG.

 

[Rick Auricchio]

Q is indeed the width of the boost/cut. For example, a 1 octave Q at 800 htz, will boost/cut frequencies within an octave of 8000 htz.

Correction: Within an octave of 800Hz, which means between 400 and 1600Hz.

 

[Rick Auricchio]

The diagram you put up is more familiar to me, based on full featured compressors I'm familiar with. That sort of layout and feature labeling would be a must if they decided to go forward with this.

Thanks. I drew it in order to clarify the parameters for our testers. Making it look familiar is important to actually trying things out.

I just corrected the diagram. I had left out the Gain for each module.

I know nothing about firmware, would it make sense (is it practical) to update the firmware or would current owners be out of luck?

Usually the firmware is contained in a read-only ROM or an erasable one (such as flash). Depending on which it is, one must either swap the ROM part or reload firmware via a connector. That connector may be either the 5-pin remote connector, or an internal connector on the board.

So, although firmware is generally able to be updated, we know nothing today about if and how it would be accomplished. We all have to stay tuned.

 

[OhulahanBass]

Hmm, seems in the original post they have been using the software on RH450s since the begining... I'm maintaining hope. As for the Q def.... Q just got interesting to me. Sounds like what TC is getting at is truely allowing artists to completly personalize their amp...did someone say Bass Amp 3.0???

Wow, TC rocks! I can't wait to have time to look into their other products like recording gear, these guys and gals are awesome!

I am very excited to see more posts, reviews and vids, thank you testers.

 

[Passinwind]

Correction: Within an octave of 800Hz, which means between 400 and 1600Hz.

Nope, neither one of you are quite right. The -3dB points are an octave apart in a one octave bandpass filter. And the Q for that filter would be 1.41.

Invalid Link Removed that may confuse you even more, or may just help.

So a one octave parametric constant-Q EQ (ie a "true fully parametric" one) centered at 800 Hz will have -3dB response at 565 and 1130 Hz, approximately.

 

[Rick Auricchio]

Shows how little I know about the details of EQ...

 

[Passinwind]

Shows how little I know about the details of EQ...

Don't sweat it Rick, I had to refresh my memory before I posted. And when I build DIY stuff I still always have to actually measure what I'm getting, at which point I usually just end up using my ears like most people do anyway.

 

[OhulahanBass]

Nope, neither one of you are quite right. The -3dB points are an octave apart in a one octave bandpass filter. And the Q for that filter would be 1.41.

Invalid Link Removed that may confuse you even more, or may just help.

So a one octave parametric constant-Q EQ (ie a "true fully parametric" one) will have -3dB response at 565 and 1130 Hz, approximately.

That clears it up, thank you for the link!

 

[Eublet]

Nope, neither one of you are quite right. The -3dB points are an octave apart in a one octave bandpass filter. And the Q for that filter would be 1.41.

Invalid Link Removed that may confuse you even more, or may just help.

So a one octave parametric constant-Q EQ (ie a "true fully parametric" one) centered at 800 Hz will have -3dB response at 565 and 1130 Hz, approximately.

For sure, and this is a good reason why the RH450 default settings (along with the Classic450) work SO well for plug-and-play bassists. The 2.1 ocatave Q means that the 4 knobs on the panel are "connected" to each other at the fringe edge of each frequency range on the knob. It creates a more musical experience when cutting or boosting, and can especially prevent users from double boosting a certain area which can really get things out of whack.

I have pretty much come to the conclusion that, for me personally, I love the EQ settings that TC has chosen already, and really don't need to adjust them at all. They just work, with the caveat being that you have a bass that sounds good without any EQ applied. If that's the case, then even in boomy situations because of bad room acoustics, the default settings let you get the job done.

Because of this, I've found that I use the presets less and less, at least for EQ'ing. The most I do is use one for my basic tone, another for a bit of compression and extra gain for slap, and a 3rd with a bit of extra tubetone dialed in. The EQ is almost identical on all three. I'd trade the semi-parametric EQ control for a dedicated AND storable Tweetertone control in a heartbeat if I could. The ability to also save Tweetertone settings in would let you do a lot of cool things on the fly, so it would be nice to have a couple more preset buttons as well. That way you could save a modern, pingy slap tone with a scooped middle, or a 70's style grindy slap tone with mids boosted and highs rolled back, yet you would still have room for a few other settings.

But even then, I don't really have to change tones on a gig much, at least not to that extent. Going fingerstyle to slap is enough of a change, regardless of whether the tone is pingy or mellow.

I know I keep coming back to this, but I think the RH450 is about perfect as it is. Even if it had a tweetertone knob, I'd still leave it set low pass around 5k most of the time.

 

[Jazzdogg]

I'm interested in finding out how suitable the RH450 is for doublers who want to be able to use it for DB, EUB, and slab, and the extent to which the RH450 can be adjusted during a gig to combat piezo honk, feedback, and acoustic anomalies.

 

[KJung]

I've been thinking on this Ken since I replied to you. Thing is how do I get to try one of these things? I have one music store in my immediate area. Until recently I hadn't seen a Mark Bass product. They are supposed to be coming out of the woodwork and are distributed from Mississagua. That's the next attached city west of Toronto. I've seen one in my local store. Never even seen the Rebelhead. I believe that had I been selected for the test I would have bought the amp.

I was just funnin' with you a bit In the US, the safest way to try these heads (Genz, Markbass, TC, whatever) is to order from Musician's Friend, which has a no questions asked return policy. So, you are only out the shipping if you try it and don't like it. Not sure if there is a similar mass retailer in Canada.

 

[KJung]

I know I keep coming back to this, but I think the RH450 is about perfect as it is. Even if it had a tweetertone knob, I'd still leave it set low pass around 5k most of the time.

This is an important point. When you extend the top end of the RH450 (or any amp), there are positives and negatives. On the positive side, of course, you get a more open, modern, airy, top end. However, you lose that ability to crank the treble control a bit and generate that upper mid/lower treble grind that sounds so good in a mix in many contexts.

The tweetertone (which again, from what I understand is just the variable lo pass that we are messing with on the software controllable with a knob on the new combos) allows you to do both, which is great. That control is kind of the yin yang of the wonderful VLE control on the Markbass amps, that is also a kind of 'variable lo pass' filter. The MB heads are voiced 'wide open' up top, and the VLE can be used to control the top end (and even the upper mid response when cranked), and was also designed (as far as I know) as a kind of 'front of the amp' tweeter control originally.

 

[KJung]

That clears it up, thank you for the link!

One thing to remember here is that the Q distribution is a sort of 'bell shaped curve'. So, even though it impacts frequencies around a center point, it impacts them much less (i.e., the boost or cut results in a lower db impact) the farther you get away from the center point. That's why it is sometimes difficult to hear the difference between, for example, a full octave versus half octave Q setting on an amp. It is relatively subtle IMO and IME.

 

[KJung]

I'm interested in finding out how suitable the RH450 is for doublers who want to be able to use it for DB, EUB, and slab, and the extent to which the RH450 can be adjusted during a gig to combat piezo honk, feedback, and acoustic anomalies.

That's a tough one. On the positive side, four bands of semi-parametric EQ is very powerful. On the negative side, the Q's are quite wide on the midrange, so you don't have the ability to 'notch cut' to control wolf tones or feedback in very specific frequencies with DB. Of course, not many amps have this ability anyway.

Also, the presets are wonderful for doubling, since everything (EQ, compression, input gain, post EQ volume, etc.) is storable. So, it is easy to have totally different voicings, input gain, etc. for your slab versus DB at the push of a button. The only downside versus a true multichannel amp is that you still only have one input... so you would need to plug and unplug the basses when switching on the gig.

Regarding piezo honk, the tight, warm voicing of the RH450, along with the relatively high input impedance would make this amp appropriate for piezo pickups (i.e., the amp natural rolls off deep bass and upper treble... the typical problem areas with piezo pickups), although I'd never use a pure, raw piezo signal without some sort of buffering anyway.

For those DBers who like a very articulate midrangey tone (like using the little GK MB150 micro combo), this head would most likely do the trick. It of course sounds awesome with slab, and will do everything short of full Marcus Miller uber sizzle.

 

[relwof]

You misunderstood his email. That's not exactly what he was saying....

I think the only thing clear in Uffe's original email is that from the COMPUTER (PC/Mac/???) side, it looks like MIDI. Unfortunately, this does not mean the RH450 itself is MIDI capable.

This is a two part rig, you need BOTH the tweaker software AND the special firmware in the RH450...

I also don't mean to nitpick but, before it gets any more confusing,- there's actually three parts if you include the "special MIDI cable". And of course then there's the MIDI interface, and the PC, and you probably need a bass, a cabinet or two, a 120VAC power ou**SMACK** ok, sorry.

Also, a general point, it's only a MIDI cable if it's MIDI running on it (which we don't know). It's just a 5 pin cable that adheres to a Link Removed standard.

And the 5-pin DIN on the back of the RH450 is certainly not a standard MIDI interface as used by the Tweaker software, since it needs bi-directional I/O (so you would need two MIDI sockets - an in and an out ). OTOH, it is plausible that, since most MIDI gear doesn't need all five pins, they wired it like a MIDI "in" port and used some of the extra pins for the "out", hence the need for a splitter cable. Especially since TC it appears did exactly that some of their guitar products (like the NDR-1 Nova Drive). But it also seems they used one pin for power (so the RC4 remote footswitch can have pretty blinky things without batteries), which I don't think they needed with the NDR-1, so it could be totatly different.

Bottom line, until we know otherwise from Uffe, it's just a serial interface running the MIDI bitrate using the same kind of line drivers MIDI interfaces use (since it mates with the MIDI interface we were given). Other than that, we don't know what protocol it's running, and I wouldn't necessarily assume MIDI.

So if I'm reading this correctly, you connect a normal MIDI interface to the PC, then two MIDI cables between the interface and the "special MIDI splitter", which finally connects to the RH450, right? If that's the case, and you really want to know what protocol it's running, I'd be happy to tell you exactly what they're doing. Simply send me the cable, software, and RH450 test unit... ; )

... People are gonna' read our posts and start their imagination churning with possibilities...

Can't imagine who would do anything like that...

For example, if they were running the MIDI protocol, then it would clearly have been their intent to integrate with things that know how to speak MIDI to devices and control things.

And I'd still love to know - just out of curiosity about the creative, engineering, and business decision process involved - why they didn't have MIDI from the beginning, since they already support it in other products. Of course that's just me, I'm a bit obsessed about that question across the bass gear market.

Otherwise, they could just be using a MIDI interface as a convenient way to have an opto-isolated serial interface available, which could be running something completely proprietary, geared specifically for their needs, in which case integration with actual MIDI controller devices wouldn't be viable.

Well, yes and no.
On one hand, it sounds like the test setup provides bi-directional interactive control of all the normal settings you can get on the front panel and the ability to save/restore preset configurations. That makes it 100% feasible to integrate with MIDI controllers, although it might take some additional external magic (like a box which translates from proprietary TC data to MIDI CC and sysex) and special firmware in the RH450.
OTOH, much as I hate to say it, just because TC has a way to get the RH450 to connected via MIDI-ish serial I/O does not mean that such connection is a "viable" option for the current hardware design. It is possible that they are using some creative tricks at the signal (REMOTE port may not be properly buffered/isolated for safe use with any old MIDI gear) and software (like bit-banged I/O instead of SPI/UARTs) level which could potentially degrade the performance or even risk damaging the hardware (which might be part of the reason they shipped out test units). Just because it works doesn't mean it's something they could ever responsibly release in this form as an option for existing RH450s.
Don't get me wrong, I really really hope that is not the case, and I would LOVE to see a MIDI interface option for the RH450s. But until someone from TC informs us otherwise, we can't assume this is something they could simply do if they wanted to based on what we've heard in this thread. Even if they could offer a bulletproof solution, it might require firmware a upgrade and $500 price tag to recoup the design cost for something only a fraction of RH450 owners might buy.

 

[LM Bass]

I use the RH 450 with double bass and electric bass. I feed both instruments into a Raven Labs MDB-1, then I use the presets and footpedal from the TC for the different sounds I need -electric, pizz, arco.

 

[relwof]

... The only downside versus a true multichannel amp is that you still only have one input... so you would need to plug and unplug the basses when switching on the gig.

So just how rare is switching basses mid-gig these days? Trying to figure out the best way to do that. The two input SansAmp Bass Driver Deluxe looked promising, but I stopped by Guitar Center in Charleston to try one out and it just didn't seem to have enough flexibility in the EQ to find the right sounds with my WAV4 EUB. Needless to say, the four band semi-para EQ in the RH450 sounds very promising, even if it means a separate switch box to avoid plugging/unplugging when changing bases.

... would make this amp appropriate for piezo pickups ... although I'd never use a pure, raw piezo signal without some sort of buffering anyway.

That's got me wondering, since I've never dealt with piezos until now. Seems like while I might do OK straight in from the passive piezos into the RH450, I'd be better off with at least an impedance buffer to keep the pickups happy. But where do I find something like that? Short of a full preamp (which seems like overkill if I'll be using the pre/EQ/DI in the RH450), I don't see much available unless it's out there and I just don't know what they're called yet. Might just have to so some soldering.

So any recommendations on a simple, small, but high quality switch box to select between multiple basses? Maybe with buffering on one side?

 

[Rick Auricchio]

....like bit-banged I/O instead of SPI/UARTs...

Oh, man, I haven't thought about bit-banging a serial port since my early Apple days, working on the Apple II.

(For those unfamiliar, this process involves using software to send every single bit on a serial interface. It saves money in hardware, because the CPU does the work of a serial interface chip.)