Bluefinger
20 posts
Feb 01, 2010
2:23 AM
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How do you guys handle these (or any other harp with slotted coverplates)?
After playing Seydels for a while I bought me a MB and a MB Deluxe to see how i would like them. I think they are great, especially when played accoustic but I have a problem when using them with a bullet mic. They feed back like crazy. I never have that problem with closed covers. I think the problem is that I can never cup them tightly because there is a lot of air leaking through the slots. Even when I open the cup on a non slotted harp for a brighter tone it does not squeal but those MBs are out of control. Is there a trick in handling Marine Bands?
thanks!
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Bluzdude46
425 posts
Feb 01, 2010
2:54 AM
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If you are used to seydel and changing over to MB understand that MB's are louder (even without opening the back) then Seydels I and a few guys from the Frederick Harp club proved that one day and I've played with them at home I'm convinced. You may need to adjust your Mic volume or preamp setting slightly.
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The Original Downtown Philadelphia Fatman... Accept No substitutes!
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Bluefinger
21 posts
Feb 01, 2010
3:54 AM
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Hmmm ... I have tried changing the amp settings in every possible way but I can't get anywhere near the volume level I can achieve with the Seydels. In combination with the microphone the Seydels are actually way louder. The MBs sound just thin and feed back at a much lower volume level. I am sure there's something wrong with my grip but I don't know what. Just holding the harp and mic without playing it makes it squeal which doesn't happen with the seydels (or any other closed cover harp like Special 20, Pro Harp, Blues Harp, Lee Oscar ...)
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ZackPomerleau
599 posts
Feb 01, 2010
4:05 AM
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This is interesting, I have never had this issue, what amp are you using?
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Bluefinger
24 posts
Feb 01, 2010
4:09 AM
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Tweed Super, Tweed Pro, Pro Junior ... mics are JT-30 with Shure CM element and JT-30 with MC-151 element ... same effect with all mics and amps so it must be the player ... damn!
Last Edited by on Feb 01, 2010 4:10 AM
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Kingley
773 posts
Feb 01, 2010
4:13 AM
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Hmmm sounds like an odd problem to me. Like Zack I have never had this issue.
However you do say "The MBs sound just thin and feed back at a much lower volume level" Do you have feedback issues at all with other harps?
I suspect your cupping technique is not correct. Maybe the amp settings are also causing issue and possibly where you stand in relation to your amp.
All of these things can affect the feedback level of a mic into an amp.
Maybe you could tell us what amp and mic you are using, amp placement on stage etc. This may help to identify the problem.
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ZackPomerleau
601 posts
Feb 01, 2010
4:18 AM
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Have you tried keeping the mids and presence low, a little treble, and a decent amount of bass? I don't know if those amps have one, but maybe if they have a master volume, cranking that and using the other one for an attenuator effect would help.
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Bluefinger
25 posts
Feb 01, 2010
4:23 AM
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-However you do say "The MBs sound just thin and feed back at a much lower volume level" Do you have feedback issues at all with other harps?-
No, I don't have that problem with any other harp ... holding the mic open will not produce any feedback, even if I point it towards the amp. As soon as I cup it with a MB it starts to squeal. Sometimes not instantly but certain notes will cause the feedback to start. We play at moderate volume levels and my settings are usually bass on full and treble below half. Presence at a third or so. On the pro Jr tone is rolled back all the way.
I have just started using the harp at rehearsals (actually I'm a guitar player) and have never played it live yet. Maybe it's linked to the basement somehow. Can a certain room cause certain frequencies to feed back? I always thought my grip was fine since it worked so well with other harps ... maybe I need to adjust it with the MBs ...
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Pimpinella
57 posts
Feb 01, 2010
4:26 AM
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It's surely a problem with your cupping technique. You need to cup the harp entirely inside your hands. Your fingers and hands should form a ring that tightens at full length around your mouth and against your cheek.
Anyway in most cases you should be able to play only partially or barely cupped to add variations to your sound. If you have problems with feedback if the harp is not entirely cupped, then you probably have your amp too wide up or you're in a very small room or you should to change your position or the position of your amp...
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Bluefinger
26 posts
Feb 01, 2010
4:36 AM
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the room is pretty small actually ...
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MrVerylongusername
870 posts
Feb 01, 2010
4:37 AM
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I think that might be the problem - have you played in the basement before with your other harps? Different rooms have very different acoustic properties and can create different feedback frequencies. A room like a basement, with low ceilings, lack of windows etc... can be a feedback nightmare. EQ is going to be a help. If the feedback starts before you've even played a note it's related to the room acoustics. Start by backing off the mids and lowering the volume.
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Kingley
774 posts
Feb 01, 2010
4:38 AM
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Ok so first things first.
You're playing a Fender Pro Junior. Have you changed the V1 pre-amp valve to a 12AY7? If not I recommend you do this as this will enable to turn the amp up higher with any harp/mic.
Keep the tone control rolled off. That will also help to fight the feedback demon. If you find you do need it to cut through then don't take it above 3.
Keep the amp on the floor and behind you (or behind and to the side). If you put it on a table or chair you often increase the chance of feedback at volume.
Bass on full will also create feedback. In general bass should never be higher than 6 (however this does vary from amp to amp).
The amp placement may be the problem as well. Try standing in a different spot from the amp than you normally do.
I would recommend looking again at your cupping technique to see if that is also causing problems.
THe feedback problem could be caused by any or all of these problems.
Last Edited by on Feb 01, 2010 4:39 AM
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Bluefinger
27 posts
Feb 01, 2010
5:02 AM
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Yes, the room has low ceilings and just one tiny window.
The Pro Jr has a 12AU7 in the preamp (less than half the gain factor of a 12AY7) and the tone is rolled off completely.
The Pro and the Super do not have a mid controll but the bass on full setting is definitely the one that produces the least feedback and it's the setting that sounds the best. These tweeds do not have big boomy bass like Blackfaces for example.
I do not use the technique where I put my thumbs at the back of the harp and against my face (like Jerry Portnoy does for example). I hold the harp between my left hand's thumb and index finger and hold the mic with the third and fourth finger of the same hand. My right hand does the cupping. I hold the mic as far from the harp as possible to have as much space as possible inside the cup. I think this sounds best. I can easily close it and make it completely air tight if I want to (on a non slotted Harp that is). Some local players told me that the grip is ok but I might be wrong or might have developed bad habits ...
Anyway ... on thursday evening I might have the chance to try it in a larger room and then we'll see what happens.
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Kingley
775 posts
Feb 01, 2010
5:21 AM
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That's very strange! I hold the harp and mic exactly the same way and never have feedback problems and I always play Marine Bands.
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MrVerylongusername
871 posts
Feb 01, 2010
5:38 AM
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I'm almost certain this issue is one of room acoustics. The cup is only an issue in so much as it effects which frequencies the mic will pickup. The harp model is only an issue in so much as different harps generate different harmonics.
Sound is a sine wave - peaks and troughs. When sound reflects back on itself it reverses phase. If the dimensions of the room and the frequency of the sound are such that the source peak coincides with a reflection peak, or a trough with a trough, it amplifies that frequency. If that frequency is one that your mic is particularly sensitive to, you get feedback. Bullet mics tend to have a midrange peak.
If the source peak and coincides with a reflection trough, the sound is cancelled out
Different rooms therefore will accenuentuate different frequencies (standing waves). You can try to address the problem by breaking up the reflections; scattering the reflections in all different directions (egg boxes on the wall, cloth drapes, carpet the floor)
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hvyj
127 posts
Feb 01, 2010
5:42 AM
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I'm no fan of MBs, but all things being equal, a harp with UNvented covers is generally louder than one with vented covers, so I have to question whether the design of the MB covers is contributing to the problem.
On the other hand, in my experience, unmodified JT30s can be feedback prone.
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barbequebob
414 posts
Feb 01, 2010
9:59 AM
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With most amps, the first thing I do is turn the treble way down or totally off. Listening to guitar players who work in a music store is useless because they know NOTHING about harmonica.
The Pro Jr., which I won, I turn the tone control all the way down and I've never done swaps for different tubes in the sense of tube numbers, but got better (usually NOS) tubes of the same numbers.
The idea of the vented covers when the MB was created so that they would play louder and spread the sound over a wider area. Harps play at their loudest with the cover plates off.
As far as adjusting anything for different diatonic harp models, I frankly don't buy that at all and the real culprit generally tends to be technique more than anything else.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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Joe_L
17 posts
Feb 01, 2010
3:52 PM
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I owned a Pro Jr. It was tubed with a 12AY7 and 12AX7 in V1 and V2. I used all sorts of mics with it. I used a variety of mics, too. Additionally, I played all sorts of harps through that combo.
Never had a problem with any of them. Sounds like something might be odd with your technique.
Most of the time, I could get the volume up to about 4 (with the tone off) before feedback started. That was about as loud as the Pro Jr will get. In some rooms, I could turn up the tone control to about 4.
A Pro Jr is a pretty good little harp amp. If a person can't get some good sounds out of a Pro Jr, they've got some things to work on.
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Ryan
112 posts
Feb 01, 2010
5:56 PM
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I know this doesn't really answer your question, but I figure I'll thow it out there. At some point you may want to think about getting a Kinder Anti-Feedback pedal. Those things are amazing. Yes they are rather expensive, but it's worth it. You'l use it forever and never regret it. I would suggest anyone who plays a lot of amplified harp, and has had to struggle with feedback issues, save up for one of these pedals, you'll love it.
I know this isn't really what you were asking about, but I think others have given some good techniques to help with feedback, so I decided to throw out one more option. This isn't to say that one should rely on pedals or other technology to fix problems with one's technique. You'll definately want to get all the technique issues worked out first.
Last Edited by on Feb 01, 2010 6:00 PM
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Bluefinger
41 posts
Feb 03, 2010
2:37 AM
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Ok, I could not wait until Thursday, so I grabbed my Tweed Super and set it up in a larger room. Problem solved ... I can turn it up much louder now without getting feedback issues. It was really just the room. The MBs still feed back earlier because I have less controll over the cupping due to the slotted covers but it all happens at a much higher volume level.
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If it ain't broke you just haven't fixed it enough ...
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