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Thread: Need help narrowing down Saramonic UwMic9 issue

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    Need help narrowing down Saramonic UwMic9 issue

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    Hi, first time here - I'm a videographer for a school and just getting into the finer points of recording audio, so bear with me.

    I've been doing some tests to figure out why our videos have so much background hiss and inconsistent levels - the speaker usually isn't much louder than the hiss, and the level jumps up not only when the speaker turns their head, but also just random syllables. We're limited in what equipment we have, so it's a Saramonic UwMic9 wireless transmitter receiver, shoe mounted, and I'm testing it with two devices - what we usually use, a Sony a77II DSLR, and a Canon camcorder we don't use but I've been using to compare how they handle the sound.

    The mics are fine, I wired directly into the mic jack on the Sony and had none of the issues. I definitely think this is a wireless issue; the Sony doesn't handle audio very well at all but like I said, hard wired mic sounds fine. Recording level on the Sony is set down to 0, Saramonic only has Group A powered on, transmitter pack gain set to 28 (of 30, all the way up is a little too hot), RF strength on the Saramonic receiver is at High but it doesn't seem to make a difference... I did a bunch of tests with the Canon, which has a shoe mount with XLR inputs and an attenuation switch, and got much better results but the issue with levels is still there a little.

    This is in a closed off room with little to no outside noise, but this is a medical school so there is a ton of wiring that could be causing interference just outside the room. However, there's nothing on the RF indicator on the receiver to suggest it's outside interference. Using the Saramonic's auto scan tells me to use channel 1 every time, and I don't know how I'm gonna go through 96 frequency channels to see if there's even a difference. Help please!

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    I assume the mic is the usual clip on lavalier type, and you're clipping this to the subject as close to their mouth as possible and then the receiver goes on the camera, going into an an audio input.

    Looking at the kit - it's a bit budget but seems to offer the common features.

    When you say hiss - it could be a number of things. if the level of hiss changes as the subject moves around, it's an RF problem, signal strength based, and very common. Distance is destructive, but at close range - say up to 20ft or so, low/mid or hi power would normally be fine. Another cause of hiss is simply low mic level into the transmitter, so you try to boost it on receive and bring up the system noise. If you can manage a clip, we'll almost certainly spot the cause in a few seconds. mic placement needs to be as close to the mouth as you can get. Not clear if the system you have has an input sensitivity control - many do, and having it set too low (added attenuation) means more noise.

    Radio mics also suffer from interference, and drop outs. This isn't hiss - it's an RF issue. The most expensive radio mic system is nearly as good as a $10 cable!

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    Hospital environment probably has a lot of RF sort of stuff for patient monitoring and test equipment that puts out RF hash. Can you test this setup away from the hospital?

    Bought 2 sets off eBay bought for about $25 for each set. Does all I need/want. Better gear as the OP has should be much better
    wireless-lapel-mic-2-jpg

    About 100' out before noises up.
    Mic clipped to shirt collar video... Video cam is a cheap Canon consumer model
    https://drive.google.com/open?id=1w9..._RAD26FgFubP1V
    Mark.......

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    you must have weird hospitals in the US. Our hospitals have rather sensitive brainscan monitors, and any RF interference would be pretty critical, so our equipment is tested to stringent specs. on top of most of them are our cellular transmitters, which again, are designed and tested to NOT interfere.

    I've got in my hire stock over 40 radio microphone and In Ear Monitoring channels. They run on three UHF Bands, the 2.4GHz wireless band and have dozens of comms systems on VHF and UHF. Interference to radio mics that operate in TV channels is rarely RF hash, I'm afraid. most interference is strange noises in the b background - swooshing sounds and strange dropouts that are difficult to replicate. Co-channel interference from other radio mics is common, but much of the issues people get are down to intermodulation products. Strange mathematically derived interference products that are produced by multiple RF sources. Often a number of radio mics on scanned frequencies are the culprits. I find scanning a totally awful way to find frequencies, because all they look for are empty channels, and somebody turns on something else on a different frequency and it's not compatible and weird noises start. Sennheiser and Shure, for example publish lists of channels for their gear that can co-exist happily. Stray from these and you are on dangerous ground.

    you can also get problems from apparently empty channels. Here in t he UK, one of our old wireless mic bands now has 4G cellular activity in it. This is problematic in that is causes odd noises when the signal from the wanted distant transmitter gets weak - the cellular signal and the analogue wireless combine in unpredictable ways. Wireless is always a process that must be managed. A perfectly stable system falls when you move to a new area, or fails when somebody turns on their system in the building next door.

    interference is normal and has to be dealt with. The OP mentioned it does a scan and stops on channel one. If the two components can talk to each other on ch 1 all is well. It would only jump to 2, if 1 was occupied. You have no way of knowing if a channel is empty, or just unused at the moment.

    Wireless radio is based on solid technology, and the cheap Chinese kits now has pretty decent RF and AF performance. Sennheiser and Shure have more sophisticated filtering and the ability to be used in multi-channel systems. None of the Chinese kit I have has ever provided channel and bank lists even on the multi-channel equipment.

    Wireless systems are NEVER plug and play. I employ somebody for the important jobs to monitor, fix and manage the RF systems. They are never just sitting around, and problems are common. Money well spent. In video, we buy RF products and expect them to work well. It rarely works like this.

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    Thanks for the replies. I was in a hurry last week so I'll try to elaborate.

    Quote Originally Posted by whome View Post
    Hiss is not electrical noise from other cables.

    Whats with the need to use a wireless mike that is causing problems?
    I was pretty sure it was the wireless setup causing the extra noise, as I did test a few hardwired setups. I'm new to the department and it's just what they've been using. All I'm trying to determine is if there's a frequency I can change to or something I'm missing that will let us use the wireless receiver and alleviate not so much the noise, but the levels jumping so drastically even when the speaker is not turning their head. Or if it's just this kit is garbage (none of the reviews I've read mention any problems) or this is just how it is with wireless.

    Quote Originally Posted by rob aylestone View Post
    I assume the mic is the usual clip on lavalier type, and you're clipping this to the subject as close to their mouth as possible and then the receiver goes on the camera, going into an an audio input.
    I am clipping it in about the upper middle of the chest; even though the mics are omni, the level jumps I get make it sound like a directional mic that sometimes can't pick up around the chin.

    Quote Originally Posted by rob aylestone View Post
    When you say hiss - it could be a number of things. if the level of hiss changes as the subject moves around, it's an RF problem, signal strength based, and very common. Distance is destructive, but at close range - say up to 20ft or so, low/mid or hi power would normally be fine. Another cause of hiss is simply low mic level into the transmitter, so you try to boost it on receive and bring up the system noise. If you can manage a clip, we'll almost certainly spot the cause in a few seconds. mic placement needs to be as close to the mouth as you can get. Not clear if the system you have has an input sensitivity control - many do, and having it set too low (added attenuation) means more noise.
    Both the hiss and the inconsistent levels are only present when the wireless receiver is involved, so it's almost definitely an RF thing. With the receiver plugged into the 3.5mm mic input on the Sony DSLR, initially there was a lot of noise until I turned down the recording volume in the Sony's settings. However, after turning it down quite a bit, it was hard for the speaker's voice to get up over the noise.

    Now, when I use the wireless receiver going XLR into the Canon camcorder, the shoe mount with the XLR inputs has gain control and an attenuator switch for each input - when I keep the gain on the shoe down pretty low, the gain on the wireless receiver up almost all the way, and switch the attenuator on, the noise improves quite a bit and while there is some level jumping, overall it's much clearer. Like I said I'm kind of a novice so I have no idea what an attenuator does or if this is actually a good thing.

    Quote Originally Posted by arcaxis View Post
    Hospital environment probably has a lot of RF sort of stuff for patient monitoring and test equipment that puts out RF hash. Can you test this setup away from the hospital?
    That's probably my next step, I can't say for sure, but I feel like the worst these problems become are on two floors of the building in rooms that are just outside a maintenance shaft running all the way down. I'm not sure if having what I assume is a lot of wiring, pipes, etc. just outside a closed off room would affect the wireless signal the way I'm describing, so it's just a guess.

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    Do either/both cameras have an 'auto gain/level' function that might be enabled?
    Mark.......

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    Quote Originally Posted by arcaxis View Post
    Do either/both cameras have an 'auto gain/level' function that might be enabled?
    I thought of that too but it's hard to say. I can't find anything on the Sony a77II; I know previous models had it but this one does have an "Audio Record Level" option that lets me set the record volume, so if it is applying auto gain I'd never know. The Canon has auto or manual level settings but they seem to be greyed out when I have it connected through the XLR shoe mount, probably because it has a gain control dial. I could see how this seems like auto gain though, since the levels stay so low and then jump up during random syllables.

    I did some more tests this morning with headphones plugged into the Saramonic receiver; the noise increases for every transmitter I add/keep channel powered on for. For example, each transmitter is a group (A or B), and when I turned off the power to group B on the receiver, which is not in use, the noise decreased. Likewise, when I turn on the group A transmitter, the noise increases. So there's that but nothing really alleviates the leveling issues.

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