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Keilwerth SX90 bass saxophone (non production model, handbuilt by Martin Grünewald)

Keilwerth special SX90 bassOrigin: Germany
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 to do.
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 foreseeable future.
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 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 that.

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.

SX90 special bass engravingAt 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?
Keilwerth SX90 special bass octave mechIdeally 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 generally were.
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.

Keilwerth SX90 special bass Bis keyQuite 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.

SX90 special bass D keyVent 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 feel clunky.
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.

SX90 special bass guardHere's 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 caveats.
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 way.
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.

SX90 special bass caseTopping 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 Behemoth'.
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 your fingers.
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 site.
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 Keilwerth.
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 post setup).
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 it sounded.
D'you want the short answer or the long answer? Or both?

The short answer 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 (Conn) bass:
"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 remained.
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 contemporary.

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.

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