Rolls PM350 Input Level Question

[petesenkowski]

I play double bass, but I'm posting in this forum because my monitor requirements are not typical of most double bass players.

I run direct to the PA, and use a Rolls PM350 and hard-wired IEMs as a monitoring system. My bass monitoring is fine; it's the rest of the band's input that worries me. The PM350 has a line level input for external monitor input; my problem is that I often can get only a speaker level feed. The PM350 allows +40 dB maximum line input, and I've been using it with the speaker level feed, but the input pot is barely off the peg (between 7:00 and 8:00) when I get the volume I need.

Am I running a risk of frying the mixer with the speaker level input? Do I need some sort of attenuator for my monitor input? or does the +40 dB maximum give me enough slack?

Thanks,
Pete

[WayneP]

I’d worry about frying the Rolls too, but I expect that would have already happened if it was an issue. Unfortunely, “hair trigger” adjustment ranges like you’re dealing with are part and parcel to an exceedingly strong input signal. Is there no way you can get a line level signal from your mixer? That would be much more ideal. If not, you might look into one of those direct boxes that are designed to work with speaker-level signals, and insert it between your signal feed and the Rolls.

Regards,
Wayne A. Pflughaupt



Pedulla Club #45
Administrator, Tobias Club
Big Cabs Club #23
My Rig: Stage and FOH Friendly

[petesenkowski]

Thanks for the response, Wayne. I play in several contradance bands; we usually play halls or gyms with 50 - 200 dancers, and the sound systems vary in quality. FOH varies from acceptable to very good, but the monitoring is usually limited to one feed into several floor wedges. No one wants bass in the wedges, since they can hear bass from FOH; unfortunately, the FOH sound that gets to the stage doesn't give me the pitch precision I need to monitor my intonation; hence the in-ears; I get the same feed as the rest of the band and mix in the bass with the Rolls.

I can usually get a line level feed at our usual venue and at one other venue with an accomplished soundman. At other venues, the soundmen know just enough to set up the floor wedges, and all I can get is a series feed out of the last wedge at speaker level.

I had looked for speaker level attenuation before but couldn't find anything (keyword ignorance). After reading your post, I looked for "speaker level direct input" and found several items. The most promising seems to be the Rapco Horizon DB-101SL for about $45. I guess I'll get this unless someone has a better specific recommendation.

Thanks again,
Pete

[petesenkowski]

I bought a LiveWire DI with three attenuation levels to step down the speaker level signal from the wedges to line level for input to my PM55: speaker cable into the DI, XLR out from DI to TRS into PM55.

I've been lucky recently; I've always gotten line level monitor feeds into the board, TRS into the PM55, and all is well ... until last night. I could only get speaker level output from the wedges. I ran it as described above ... nothing. I tried all attenuation levels, including zero ... all nothing. I tried again with a different DI box ... still nothing; with a different XLR to TRS cable ... nothing again. I ended up running the speaker level input directly to the PM55 with the volume control barely off the peg, which is the situation I was trying to avoid.

Can anyone tell me what I'm doing wrong?
Line level input from board to TRS to PM55 ... fine;
Speaker cable from wedge to PM55 ... OK but scary hot;
Speaker cable from wedge to DI to XLR to TRS to PM55 ... nothing.

Any help is appreciated.
Thanks,
Pete

[uhdinator]

I'm assuming the wedges are passive and powered by an amp. If so most amps have an XLR in and a parallel out usually as a TRS jack next to the input. If so just tap off that and you are getting the same line level monitor mix that is going to the wedges. Pretty straight forward.

[Never_grew_up]

I'm in Atlanta also. When/Where are you playing? I might be able to come by & take a look.

[petesenkowski]

Originally Posted by uhdinator

I'm assuming the wedges are passive and powered by an amp. If so most amps have an XLR in and a parallel out usually as a TRS jack next to the input. If so just tap off that and you are getting the same line level monitor mix that is going to the wedges. Pretty straight forward.

Thanks, uhdinator; next time I'm in this situation, I'll look into this, and hope that the soundman is willing to let me try. At dances like this, we're working with volunteer soundmen who know how to set up a certain way and get nervous if someone tries to mess with their setup; since we're the only ones getting paid and we're treated really well, I'm reluctant to do anything to rock the boat. Also, I don't know of anyone else in contradance bands who uses IEMs; everyone expects wedges and nothing more.

I realize that uhdinator's solution is a better choice, but can anyone see why my attenuation method above (wedge -> speaker cable -> direct box -> XLR to TRS cable -> PM55) is not working?

Thanks,
Pete

[uhdinator]

Maybe because DI's should not have power from an amp ran into them. Jacking into a speaker parallel out jack is the same as running right off amp output.
No DI, mixer, headphone amp, or IEM I know of is made for that. you may have fried something if you have not already and may even damage the amp that's powering the wedges.

If it's a powered speaker and your getting line level parallel out/thru that's fine. In that case there is no need for a DI anyway to go to a mixer, headphone amp or iem's. DI is to make instrument level high impedance into mic level low impedance and makes it balanced so you can run long distance thru a snake and so signal is compatible with mixer inputs.

[MNAirHead]

this is a very robust unit...

Rolls primary customer base are architectural and church installations.

I've run a PM351 for years like this with zero failures.

Somewhere on here, there was a simple diagragm on how to build a $5 "step down box"

OR

A rolls DB25 also has an attenuator (you'd need some different cabling)

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For events like this, I commonly will place a small "wafer looking" omni mic onto a main or monitor and bypass all the gizmos.

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If I get a few minutes I'll contact their engineers and ask them specifically.

[petesenkowski]

Thank you, uhdinator and MNAirHead, for your advice.

The Rolls PM55 is apparently robust enough to handle speaker level but it still makes me nervous to have such a low input pot setting -- barely off the peg.

Based on Wayne's advice, I got a DI with high attenuation. I use a LiveWire SPDI direct box, a DI with three attenuation levels (0 dB, -20 dB, -40dB); this unit looks a lot like the Rolls DB25. I thought that by running the wedge output through this unit, I would have a more reasonable input level to the PM55.

What confuses me is that when I put the DI in my monitor signal path, I get no monitor output in my ears, regardless of PM55 monitor input pot level or DI attenuation level.

With unbalanced wedge monitor input, I get a signal, albeit a disturbingly strong one. With a balanced TRS monitor input line from the board, I get a signal that's just right, but I can't always count on this being available. When I try to attenuate the wedge signal with the DI -- unbalanced in, balanced out -- I get no signal.

I currently have the PM55 (similar to the PM351, but with 2 inputs instead of 3, and with optional 9v battery power) set for mono monitor input, which means effectively a TS input; however, a line-level TRS cable straight from the board works fine, whereas the XLR to TRS cable from the DI does not work at all.

MNAirHead, what did you mean by different cabling with the DB25? I assume your DB25 cabling method should apply to my LiveWire SPDI.

Should I be using the stereo monitor input setting on the PM55 instead of mono? I don't quite understand the distinction between TRS balanced mono (which is what I believe is coming off the board) and TRS stereo.

Thanks,
Pete

[macbuie]

Newby here! I have used a Rolls 350 for 7 years now. I play a EUB (palatino) and perform mostly folk celtic music. I have to contend with fiddles, penny whistles, guitars and drums(bodhran). When I can't get a mixer line out I use a drum mic on one of the pa speakers. Certainly not preferred but works when anything else is not an option. I also use a Fishman pro eq bass platinum preamp between the EUB and the 350. this combo gives the monitoring a more performance quality sound instead of a pre eq flat sound. However, this only works well if you mix your own eq for the front of house.

[Roadkill]

Originally Posted by uhdinator

Maybe because DI's should not have power from an amp ran into them. Jacking into a speaker parallel out jack is the same as running right off amp output. No DI, mixer, headphone amp, or IEM I know of is made for that.

Not true - many (most?) DI's have enough switchable attenuation to run off of speaker level. Even this cheapie will work:
http://www.amazon.com/Pyle-Pro-PDC21.../dp/B0027V760M
You'll have to use a XLR to TS cord on it's output though to get it into the Rolls and DEFINITELY use the ground lift!!!
Manual: http://www.pyleaudio.com/manuals/PDC21.pdf
Note the section on connecting to high level signals .

[MNAirHead]

have you called the company (in Utah)... engineers answer the phone.

I've not had a problem wiht speaker level..,. not sure it's endorsed by the company.,

[musicman7722]

A bit off subject but the 350 seems to be out of production is this true?

[Roadkill]

Originally Posted by musicman7722

A bit off subject but the 350 seems to be out of production is this true?

Replaced by the PM351 .

[MNAirHead]

Originally Posted by musicman7722

A bit off subject but the 350 seems to be out of production is this true?

Yes to can cable a 351 xlr to 1/4

[Rocksolid]

The Rolls PM57 Rolls Corporation - Real Sound - Products PM57 Headphone Tap is exactly for taking a speaker level and dropping it to phones level and it also has an attenuator.

I use a Y cable pre the Power amps to take the signal from the desk to my PM351.

[MNAirHead]

A DB25 also does this

[Jazzdogg]

According to Rolls, Max Input Level for the the PM350/351:
Microphone level... -20 dB XLR
Instrument level... +15 dB
Line level............ +40 dB

I see no rating for speaker-level inputs.

DIs, like my Countryman, that are designed to handle speaker-level inputs, typically provide a way to select the output level; if you're feeding a bigger signal than a particular PM350 input is designed to process, I'd expect it to self-protect or fry, muting the output.

When you made the same connections at home that you had on the gig, did the same failure occur? How have you been trouble-shooting?

Doesn't look like the Rolls PM351 provides any limiting capabilities. What kind of limiting are you guys using to prevent potentially deafening bursts from getting into your IEMs?

[MNAirHead]

I'd call them in Utah - unofficially I gambled with one for 18 months at speaker level-just turned down

My limiting?
When a place that I'm afraid of,

Bass-mxrm80-xlr ( mxrm80-pm350 -to Shure psm200-iem)