Keilwerth SX90 bass saxophone (non production model, handbuilt
by Martin Grünewald)
Guide price: Whatever you're prepared to pay to own it
Weight: Not light
Date of manufacture: 1993
Date reviewed: January 2007
A Craftsman's edition of a top end bass instrument
This review is perhaps one of the most pointless I'm ever likely
In general, the reviews are about instruments that are pretty much
widely available - with some perhaps being slightly rarer than others.
When it comes to this particular instrument though the rarity factor
goes through the roof, as there are only three of the beasts in
existence - and there aren't likely to be any more built in the
This model is the last of the three built (this example over the
course of 18 months) - the previous two being prototypes.
It's a variant of the standard production model SX90 bass (which
evolved out of the Toneking Special), though with a few extras -
built as an apprenticeship piece by Martin Grünewald, one of Keilwerth's
master craftsmen (now no longer with them). In terms of body differences
to the standard production model, this sax has a unique bell and
upper body tube.
It's based loosely around the American style of bass design, in
particular the Conn, which makes for a taller instrument. Basses
built around the French style (known as a 'short wrap') are more
compact - and perhaps a little easier to handle. An example of both
styles can be seen here.
It goes without saying that the most notable and visible extra
is the extension to low A.
Unlike baritones, basses are generally built only to low Bb (very
early ones to low B) - so straightaway this makes this instrument
a rarity, but not only do you get an extra note down the bottom
end, you get three up the top...as this bass extends to top F# (most
older basses stop at top Eb).
It's an impressive beast, isn't it- and I can tell you right away
that it's as heavy as it looks.
Its condition is practically perfect - the superb silver plated
finish barely has a mark on it, and such is the condition of the
action and the pads that I suspect it's hardly been played since
it was built. In fact, I had to slacken the action off in places
due to binding on the key pillars. You don't get much tighter than
So - we've established three things already. It's magnificent;
you want one; you can't have one.
Commonsense dictates that we should all pack up and go home now...but
where's the fun in that?
Modern bass saxophones aren't exactly 'production line' instruments.
The small demand for them simply doesn't make it worthwhile for
a manufacturer to build the various jigs and moulds associated with
the more popular types of sax, so basses tend to be handbuilt. This
explains the relatively high price - and shows up in the way the
horn is put together.
For example, the tone holes are soldered on (as opposed to being
drawn out of the body).
This isn't perhaps entirely due to the lack of jigs or machinery
- the metal on the bass is slightly thicker than that used for smaller
horns and it's probably quite impractical to attempt to draw a tone
hole out of it. The tone holes are silver soldered on, so there
won't be any issues with Galvanic
Corrosion in later years.
The body features the usual conveniences for the repairer, with
a detachable bell and top bow - and a very substantial two-piece
bell brace that Brunel
would have been proud to put his name on.
It also features an unusual crook arrangement, whereby the crook
fits upwards into the socket (as opposed to downwards, like any
other sax). The reasoning for this is most likely due to the fact
that basses take a lot of punishment, and because the crook incorporates
the final bow the horn can have a straight tube off the crook socket
- making it a great deal easier to take out the inevitable dents
resulting from the knocks that this tube is prone to.
Mind you, this is one crook socket that you would never want to
allow to become loose - the consequences could be extremely expensive
if it dropped out of the socket and hit the deck.
Additional detachable bracing on the top tubes adds extra support
for the substantial tubing.
this point it's worth mentioning the engraving that adorns the bell.
As can be seen, the instrument has been signed by the builder and
a rather ornate and stylish 'coat of arms' cut into the bell.
I'm uncertain as to what the engraving is meant to represent (if
anything at all, other than being decorative), but the 'horns' on
the helmet are an amusing touch, having a bassoon-like bell on the
ends (I'm told that Martin Grünewald now works as a bassoon specialist
for Püchner - which
perhaps explains the reference).
It rather put me in mind of something Vic Reeves might have worn
(international readers will probably not understand that reference
- in which case "something that one of Dr. Seuss's creations
might have worn" will probably do just as well).
The remaining pillars and fittings seem to consist largely of baritone
parts. I noted many pillars on the lower section of the horn with
'double bases' - a standard pillar and base with another, slightly
larger, base fitted to it. This isn't a big deal though, and the
addition of a larger base doesn't make the pillars look at all odd
- and makes them reassuringly secure.
There are three hefty sling rings fitted; a standard central one
and one each at the top and bottom of the body. These latter two
allow for the use of a guitar-type strap...though I'm not convinced
that this works all that well (as we'll see later).
All in all the body looks remarkably robust and well put together,
and should prove to be more than capable of handling the rough and
tumble lifestyle of a bass instrument.
Now - it's obvious that when you build a bigger body you have to
scale things up. Bigger tubes need bigger braces, bigger pillars,
bigger fittings etc. - and bigger keywork?
yes...you certainly need bigger key cups, so you might suppose that
everything else has to match.
It's here where the Keilwerth bass runs into a little bit of trouble.
The problem, in the main, is about the compromise between the required
stiffness of the keys and their weight. The longer a key barrel,
the more inclined it is to bend and 'whip' (which describes how
a key will distort when subjected to pressure). To counteract this
you could simply increase the size of the key arms and barrels...but
that would increase the weight (and how!).
What's clear, from looking at the photograph, is that the keywork
is very complicated. Older basses (and baritones) had relatively
simple actions; keys tended to be of one piece and little use was
made of 'bridging keys'. This led to the action feeling very cumbersome
and spongy in places unless the keys were built heavier, which they
The Keilwerth bass takes full advantage of modern key design; levers,
cantilevers and linkages abound in an effort to reduce the length
of key barrels and arms (the top D, for instance, comprises three
levers, and works beautifully) but in some cases the extra complexity
negates any intended efficiency.
For example, take the G key mechanism.
Play the lower octave G on any other sax and only the one key will
move - the G key itself.
Do the same on this horn and three keys move - the other two being
related to the octave key mechanism. Bring that octave key mechanism
into play and the active key count goes up to five.
Unsurprisingly the G key felt awfully stiff and spongy in operation
- however, a careful examination of the octave key mechanism (shown
right) revealed that it was possible to slacken off the springing
closest to the G key foot and beef up the tension on the springs
furthest away (i.e. near the octave key vents). This vastly improved
the feel of the G, and better distributed the spring tension around
the octave key mechanism as a whole.
Another tricky spot is the Bis Bb mechanism.
As many earlier basses don't even have a Bis Bb key it's perhaps
churlish to be picky about one that does - but the way I see it
is that if a key's there, it ought to work.
Most of the problems with the Bis key revolve around the sheer throw
of the key. The throw describes how far the key moves in use. The
average throw of a Bis key on an alto sax would be around a centimetre
- it's at least double that on this bass. The trouble is, the throw
of the Bis touchpiece exceeds that of the B key - so if you set
the Bis touchpiece so that you can roll your forefinger off the
B to actuate it, by the time the B key closes the Bis still has
a way to go...and your finger all but falls off the B key.
Set the Bis key so that this doesn't happen (by raising it) and
your forefinger rolls forward into empty space.
The best you can achieve is a poor compromise that always results
in your forefinger copping a nasty pinch as you go for the Bis Bb.
What's needed here is more of a domed affair, such as that seen
on some Borgani horns. This would better allow the forefinger to
roll forward, and the extra height of the dome would even out the
difference in throw between the keys.
why this was overlooked is anybody's guess. Perhaps it was assumed
that as so few vintage basses have a Bis key, no bass player would
have a use for it?
I also noted excessive whip in the Bis Bb key barrel, which doesn't
help the accuracy of the mechanism.
As mentioned earlier, there are a few extra keys on this bass that
aren't fitted to the standard production model. Most notable (apart
from the low A and top F#) is the addition of a mid D vent (the
topmost central cup in the photo above right). This key was added
by the builder at a later date - presumably as part of the ongoing
research and development project.
The vent sits near the top bow, so the linkage that connects it
to the low D key has to run the entire length of the body - and
is split into two keys.
Mid D has always been problematical on basses - and most players
of older basses either get used to it or develop 'false fingerings'
that help improve the clarity of the note - so an automatic mechanism
that cleans up this tricky note is a welcome addition.
Thing is, whilst it works it does so in a slightly kludgy manner.
keys, as the name suggests, tend not to need to open as far as normal
keys. In some cases the merest crack in the seal of the pad is enough
to allow the vent to do its job. In this case I found the vent key
needed to open about three millimetres, and that's a huge difference
to the three or four centimetres that the D key has to travel -
and so there's lost motion that has to be taken up by the vent linkage.
It does this in a very crude way; the actuating lever hangs above
the D key foot (seen on the right) and only comes into play just
before the D key pad hits the tone hole. This makes the D action
If you adjust the linkage so that it always remains in contact with
the D key, the feel improves considerably - but the vent cup opens
about a centimetre...and as it remains open when you play an Eb
it almost completely kills the note.
There's not much that can be done about it. Ideally yet another
link is needed from the Eb touchpiece to close the vent key - but
this would be horribly complex. A better bet would be to fit a foot
to the vent key that limits how far it can open (it could be made
adjustable too, to allow the player to fine tune the tone - the
existing link does have some degree of adjustment, but it's rudimentary
at best) - which would allow the link mech to remain in contact
with the D foot. There'd still be some double action, but this design
would shift it to the top of the action rather than leave it on
the D key, where it hampers the feel.
a cheeky feature related to the D vent mechanism - this is the guard
that protects the long key barrel seen disappearing off to the top
right in the photo above. In order to make up a guard of sufficient
length, the builder has 'cut and shut' two smaller guards together.
I shan't knock off any points for this oversight, seeing as how
the D vent was a later developmental addition - and given the superb
build quality throughout the rest of the horn - but if the builder's
reading this now I bet he's thinking "Bugger, I knew I should've
sorted that out!".
It might seem like a boon to have a top F#, but there are a few
There's no front F key. I'm not entirely sure why not - it's perhaps
because the necessary linkage would prove to be too complex to work
properly, but the lack of it renders the F# pretty much unusable.
For sure, you can get the F# by using the palm keys and the lower
F# key...but this is big bit of kit and complex fingerings can be
extremely tricky at any sort of speed.
The other thing is...why bother? Why buy a bass that goes up higher??
Which brings me nicely onto the low A mechanism.
Now this is more like it.
Having a low Bb is a prize enough - but a low A is the icing on
the cake. And the cake itself. And the oven.
The extra tubing this requires is phenomenal, though the keywork
involved is rather less complex. Low A mechs have always been prone
to 'whippage' - the fact that most modern mechs operate off an additional
thumb key and require a link that runs right over the body means
that a mech that's anything less than perfectly designed and built
will feel awfully spongy.
So I was pleased to see that the Keilwerth bass had a suitably robust
mechanism. Interestingly, it isn't as beefy as the low A mech found
on the Yamaha baritone - but it's adequate, and seems to work quite
well. Well enough in fact to allow you to get a low A without having
to use the left hand spatula keys (for the low B/Bb) for assistance.
Mind you, it's not exactly what you'd call slick in operation.
I remarked above that some of the bodywork looked like baritone
parts that had been adapted to fit, and this holds true for the
keywork in places. I felt that the keywork would benefit from some
additional bracing in places, especially on the right hand key stack.
Many repairers will know how badly some vintage bari right hand
stack mechs can flex, and this bass suffers from the same problem.
For the player this translates into a spongy feel - every time you
press a key down that is connected to another key (say low F, E
or D) a certain amount of motion is 'lost' as the key takes up the
flex in the linkage of the key it's connected to.
Beefing up the action doesn't have to mean thicker keys - improvements
can be made by using square section links, or by fitting additional
(but small) bracing arms. Similarly, I'd have liked to have seen
better use of anti-whip pillars. I know Keilwerth know how to do
this because I've seen them on the straight
alto. There are a few such pillars fitted, but these are more
for protection of the barrels rather than a dedicated means of preventing
long key barrels from flexing.
From a purely mechanical perspective this bass sits in two camps.
On the one hand it makes use of modern key design that enables the
fitment of more notes and additional keys - which is a good thing;
but on the other hand the additional complexity almost gets in the
I've seen this before, on a Boehm system bassoon. Beautifully complex,
full to bursting with gadgetry but very difficult to play with any
degree of deftness.
it all off is a truly gigantic case.
I appreciate the difficulties in designing a case for an instrument
of this size, but then it's well known that heavy instruments get
bashed about, and I'd liked to have seen a better attempt made at
putting some decent padding in the case. The bottom bow area in
particular is extremely vulnerable - and hideously expensive to
fix if it takes a big knock.
Likewise, would it have been too much to ask for a dedicated compartment
for the crook? There's plenty enough space in the case, and I wouldn't
relish the thought of a critical part of the horn rattling cheek
by jowl with mouthpieces and other assorted gubbins.
But enough of all that!
That bass instruments are unwieldy is a fact of life - but who buys
them for their light touch? No-one, of course - people buy them
for their sheer low-end grunt. But does the Keilwerth have it...?
For the play-test part of the review I was joined by the (it has
to be said) proud and somewhat paternal ("Ooh, careful..have
you got it? Steady now! Left hand down a bit...") new owner
of the instrument, Rhys David; and the incomparable Mr.
Pete Thomas - who undoubtedly knows a thing or two about bass
saxophones. For the sake of comparison, Pete had brought along his
Buescher True-Tone bass...a stalwart among vintage basses.
There was absolutely no doubt the Keilwerth was coming - you could
hear it...or rather you could hear the puffing, grunting and cursing
coming from Rhys as he manhandled the huge case out of his car and
into the workshop.
The puffing and cursing continued as the case was opened and the
bass was lifted out - it weighs a ton!!!
OK, slight exaggeration there - in fact it weighed a tad under 22
pounds, or a hair under 10kg.
Compare that to Pete's True-Tone bass, which tips the scales at
around 16 pounds (7.25kg). Hefting the Keilwerth round your neck
is like hanging Pete's bass round your neck...then adding a tenor
sax. That's heavy.
Impractically heavy, it has to be said.
It's quite a feeling to have several grand's worth of unique brasswork
dangling round your neck with nothing but a nylon hook to stop it
crashing to the ground - and good though I know my BG strap is,
I wasn't completely sure that it was designed to cope with the sheer
weight of what I soon christened 'The
It wasn't all that playable on the strap anyway - by the time I'd
adjusted the strap to get the mouthpiece to the right height, the
buckle was so far up that my neck was being constricted. I'm pretty
sure a standard strap is unsuitable anyway, even for short periods
of time, due to the sheer weight of the horn.
The additional strap rings that allow you to use a guitar strap
looked interesting - but the problem remains one of angle. Both
the standard strap and a harness seem to force you to lay the bass
almost horizontal (so you face downwards in order to play) and the
guitar strap proved little different - although slightly more manageable
in terms of the weight.
We considered the possibility of moving the strap ring even though
the horn was perfectly balanced in its current position - if it
were lower it might allow the player to stand up straighter, but
then this would be at the cost of the balance of the horn, and when
there's 22 pounds on the end of a strap you really don't want to
run the risk of having to support half the weight of the horn with
Pete's bass was sat on a SaxRax
stand, and whilst this was intended for the older style of bass
we could just about manage to prise the Keilwerth onto it. I understand
that SaxRax make a beefier playing stand for bass and contrabass
saxes, but at the time of writing it wasn't yet advertised on their
Having thus decided that the only real option was to play the Keilwerth
on some kind of stand (I wonder why, unlike the Selmer, they didn't
fit a spike), we set about making the thing play.
I spoke earlier about how the complexity of the keywork can affect
how a horn feels in the hands, and this was very noticeable with
The True-Tone, by comparison, is almost prehistoric in mechanical
terms, and yet it felt more responsive under the fingers.
More 'organic', I proposed - you really felt in contact with the
horn. The lack of complex linkages and levers meant that each key
had an individual feel. The Keilwerth felt more positive - but you
felt somewhat distanced from the action (if you'll excuse the pun).
We tested the horn prior to my setting it up, and as such it was
noticeable that it needed some work in terms of balancing out the
action. The G key felt extremely slow, as did the octave key mechanism
- and a poor setup on the mid D vent made the transition around
the note rather hit and miss (these issues were satisfactorily resolved
The top F# proved to be entertaining...without the help of a front
F key it appeared to be impossible to get one's hands around the
mechanism, even more so if the horn wasn't supported on a stand.
It's not that the keys aren't where they're supposed to be, it's
just that everything seems to move that much further when you press
it. Likewise the Bis Bb key was all but unusable in any real sense
(and still is).
I didn't notice any particular problems with the layout of the
keys, but Rhys found the palm keys rather inaccessible and Pete
felt the right hand trill keys could have been better placed - and
even with the increased size of the bell keys, the spatula keys
felt comfortable and positive.
And so to the bit you've all been waiting for...how it sounded.
D'you want the short answer or the long answer? Or both?
The short answer is...it sounded like a baritone.
As much as I'd like to wheel out the adjectives and rattle on about
sonority and gravitas, it just didn't have it. At least it didn't
have it in terms of what I'd expect from a bass. Make no mistake
though, what it does have is impressive! That low A has to be heard
to be believed - it fair rattled the woodwork in the workshop, and
it slipped out with credible ease too.
Tonewise it was hugely interesting to contrast the Keilwerth's response
to that of the Buescher. I think what I was looking for, hoping
for, was the sort of response I'd written about in the Bass
Sax article in the Notes section, which refers to a Pan American
"I think the overwhelming impression was that of wistfullness.
The bass sax is, in fact, a crooner - as mellifluous as any of Bing
Crosby's best boo-boo-booing, and with a lightness of tone that
belies its great size."
To the True-Tone's equally mellifluous 'Boomp Boomp Boomp', the
Keilwerth went 'Bloort Bloort Bloort'.
Bags of attack, huge resonance, but not as much depth as the Buescher,
and nowhere near the roundness. We experimented with mouthpieces,
but as much as these changed the sound on both basses, the difference
Subsequent to this test Rhys brought along a selection of baritone
mouthpieces to try...and of all these we felt that a Selmer Soloist
and a Buffet piece fared best, bringing a greater sense of depth
to the tone - though still nowhere near that of the Buescher. This
is most likely because these two pieces have rather large tone chambers.
On the whole, bass players tend to favour the use of baritone mouthpieces.
This is chiefly because they're more widely available and there's
a greater choice of lay, tone chamber and tip opening. In a similar
fashion, baritone reeds are easier to find.
It would be interesting though to see what difference a dedicated
bass mouthpiece (and a bass reed, with its wider tip) would make.
The horn came with a Zinner bass piece - but this had a modified
baffle in it, and wasn't all that pleasant a blow.
I got very good results using a bog-standard Yamaha 5C bari piece
- the horn blew well and easily, though the tone was definitely
To be sure, the precision of pitch on the Keilwerth is everything
you'd expect from a contemporary horn - but perhaps the payoff for
that is a less individual tone.
In terms of balance across the range the Keilwerth does very well,
it has a cohesive tone overall. The only iffy point is around the
mid D, where the vent key does a great job of lifting the normally
dead tone, but does nothing for the Eb. It's nothing major, mind
you - nothing your embouchure couldn't tweak on the fly - but some
players may find themselves resorting to the old trick of using
the palm key D and Eb (minus the octave key) to get a more balanced
tone over these notes, in spite of the advanced keywork.
My feeling though is that even with a bespoke bass mouthpiece you're
never going to get the lyrical qualities that older basses have.
It seems to me that whilst you can probably knock a lot of the brightness
out of the tone, you can't raise that characteristic lightness that
basses have...that wistful, soulful quality. Of course, this raises
the question of whether you'd actually want that.
Well, the thing is, what else would you want a bass for?
For sure, there's nothing to stop you using a bass sax in a contemporary
setting - and if that's what you want to do then this bass would
be superb, but most bass buyers are going to be using them in a
more 'traditional' setting...and if they used this bass, what would
they have? Just a bari that goes down lower?
It is, of course, impossible to make comparisons with the standard
Keilwerth bass (at least without the benefit of having one to review).
I would suspect that it follows the pattern of low Bb versus low
A baritones - whereby the low Bb variants tend to have a more rounded
tone and the low A models more grunt. If that's the case then the
standard Keilwerth bass becomes a more appealing prospect.
What of the alternatives though? Well, in terms of new basses there's
the Selmer, at £19,000, and Keilwerth's production model SX90
at £15,000. After that you're into the realms of used basses.
But what of the Chinese?
As far as I'm aware there are two Chinese basses on the market at
the moment; one is a Selmer-style bass, the other a vintage-style.
I reviewed a vintage-style
bass in 2014 and found so many build-quality issues with it
that I couldn't possibly advise anyone to buy one. The Selmer-style
basses may be better, though.
For what it is, this bass is superb - no question about it - a
real credit to Keilwerth and, in particular, Martin Grünewald, the
builder. If all you need is sheer accuracy of pitch, a contemporary
feel to the action and a modern tone then this bass has it all -
plus the obvious extras in terms of the additional range....but
shoot me down in flames if I say that in the company of other basses,
the Keilwerth stands to one side, not quite part of the crowd, though
undoubtedly a member of the club.
This, I would say, is an Uber-Baritone.