Rob Danielson wrote:
> Walt--
>
> Congratulations. This could be a break-through for DIY, low-cost,
> high-quality mics. Based on your two examples, the MKH-110's sound
> is very comparable to the 20's. I agree the bottom end seems more
> defined. I'm imagining many uses already.
I'm not willing to commit quite that far yet. But it's very hopeful. If
it keeps on doing good I'm going to be happy. I went into the 110's just
to get some experience with the SASS without a big investment. Right now
it does look like they are in the same ballpark as the 20's. It's a
different sound, that's a matter of taste, but about the same clean feel
to it. In some ways the 110's are more precise and defined than the 20's.
I definitely expect to try them for my frogs in a thunderstorm series of
recordings. The MKH-20's don't give near as realistic a thunder, at
least based on some whimpy half hearted tries I listened to yesterday.
It almost gave me my thunderstorm to record. Things like rain are a
challenge. How cleanly the drops are recorded and such like. Easy for it
all to just mush together.
It's a lot less money than a pair of MKH-20's. I'm estimating everything
I have in the SASS/MKH-110 would be under $500 for mics, Crown's parts,
lathe materials and electronics. By comparison, I've got about $1400 in
the SASS/MKH-20 for the same list, and that was a unusual low price on
ebay for the mics, with new mics it would be $2500 or so. There's a pair
of MKH-20's on ebay right now, and the reserve is at $1400. There is
also a MKH-110 at $99, from the same place that's been auctioning one
after another from which I got mine. I have no idea how many more they
have to sell.
You should be aware that if a MKH-110 dies you probably can't get it
fixed. Sennheiser USA certainly seemed to be in the dark on them.
As it sits right now I'm expecting to have to cart both around. I need
some frogs to sort the two out. That's one of the down sides of a SASS,
a carry case is big as there is no small dimension. I'm still working on
that end. These won't fit in the original SASS-P case without remodeling
the foam due to the mics sticking out the back. I've considered removing
the support from the housing and building some sort of design that
sticks out less, to get the storage size down. Accommodating that
support adds a couple inches to the needed case thickness.
> Easy for me to write, but I'd love to hear the 20's and 110's cranked
> 75%+ on the MP-2 in a large interior room with no source of sustained
> Hi Hz. Room tone is rich in low-mids and should reveal inherent
> noise adequately. Possible to use no bottom end roll-off on preamp
> and recorder? No filtering might test whether the SASS mount is
> adequately immune to transmitting vibration and the interior might
> give some clues as to how well the SASS is rejecting reflections.
> Obviously, if the noise is comparable, your schematic will be very
> much in demand!
Nothing in my house would do that, the mic picks up virtually everything
in the house, to even get a quiet house I'd probably have to throw the
main circuit breaker. Not really big enough rooms anyway for the type of
sound you are thinking of.
When I was breadboarding, I was near the computer. An amazing amount of
strange thumps, clanks and whines come out of that. Most you don't hear.
I can see why the 110 was used as a test mic for listening to machinery.
The thunder I recorded earlier is done with no rolloff. Though it was
done without the pre and has the whine. I've been hoping for another
thunderstorm to get a new low end recording. Hate to just record the
rumble from the power plant or such like. If anything the 110's put out
almost too much low end. They do it cleanly, and don't overload, but
it's a part of their sound. A couple of my 110's did come with their
original Sennheiser test chart. That shows them flat up to 5k, then rise
to a peak of the hump at about 12k and fall off sharply above 17k. The
top of the rise is up to about 23 mV/Pa against the level area with
stays between 20-21 mV/Pa. They cross the 20kHz line at 18 mV/Pa Both
charts are much the same. Unfortunately Sennheiser begins the testing at
50hz, so we don't know on the lower stuff.
The mount is pretty immune to vibration in my setup primarily as the
mics are floating on O-rings inside the delrin supports. In fact in the
MKH-20 version I did not even use a setscrew, the O-rings retain the
mics fine. If I was building the 110 again I'd do it that way, may at
some point redo it like that, it would require new support and reboring
the back plate. You still cannot go hog wild hand holding them, but it's
pretty easy. The original SASS-P by comparison is very sensitive to
vibration, lightly run your finger along a cable several feet from the
mic and it will pick it up, don't even think about touching the housing.
You have to be very smooth hand holding that one. Cables can't even
wiggle. Clearly it was designed to sit on a support.
Self noise of the MKH-110's is rated at 16dBA, the MKH-20's at 10dBA.
Either of them I've not noticed anything clearly self noise, even with
the MP2 cranked all the way up and listening through it's headphone amp.
That may be partially because there are not many environments quiet
enough around here, so environmental noise masks it. I should be able to
get the gain high enough to hear it. Note you can only crank the gain
that high if it's a quiet environment, otherwise you will be seeing lots
of red indicator! Lang's comment on the quality of the MKH-20 noise
floor was that it was a smooth hiss, could intrude without being very
noticeable. If the 110 is the same that could explain not hearing it so
far. It does not appear like it's going to be a issue in actual recording.
The MKH-110 version, with it's battery and so on is a little heavier
than the MKH-20 version. If I wanted to record much longer than about 15
minutes at a time I'd probably put them on a support. If it's a pretty
quiet environment you might have to anyway so you could back off far
enough to breathe without being picked up. At high gain you almost have
to hold your breath. Right now the MKH-20 has a light plastic handgrip
out of a Sennheiser suspension system, and the MKH-110 has the Crown
metal handle, and that's some of the weight difference too.
>Thanks for the persistence!
I don't like losing. I'm not completely happy with the solution, and it
probably could use some fine tuning. But at least it appears to be
running ok. More testing to be sure. I can get on with why I built them.
Walt
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