Tweeters — Just for slappers?

[Jean-Luc Pickguard]

I've always used cabs without tweeters. I predominently play mustang basses with stainless flats, so I'm not expecting anything particularly shrill to come out of my amp.

 

My amp is a lovely Ashdown ABM600 Evo IV. I keep this at the guitarist's studio where we rehearse and I use the cabs he already had in the studio - an Ashdown ABM 115 with an ABM210 with tweeter on top (in portrait mode rather than landscape if you get the drift. I'm not sure what generation the cabs are, but they're probably at least ten years old. I kind of recall switching the tweeter off on the 210 when I first set it up, but at the rehearsal this week the bass rig was hissing very noticably, so I'm guessing the tweeter switch got knocked back to 'on' when the cab was in transit from the last gig.

 

The thing is that I have rejigged my pedalboard and at the beginning of the rehearsal and spent some time adjusting the eq on the amp which resulted in a slight bass cut and a slight boost to the mids. I'm pretty sure I kept the treble roughly flat. Listening back to the recording of the rehearsal confirms that the bass tone was the best I've had in living memory but the hiss was very noticable. i think the slight bass cut removed some mud and adding mids added clarity. I also had the volume a bit higher than usual which enabled me to play (fingerstyle) with a lighter touch.

 

We're rehearsing again on Monday and I'll try to keep the same settings but check the tweeter switch and A/B with it on/off.

 

Will switching it off take away some of what I liked so much about the tone I got this week? or should the tweeter only really concern itself with the very high slappity thwackity frequency range which would be absent from my signal?

 

I'll report back with my findings next week, but I'd be interested in what others think about this.

 

[Lozz196]

I play similar basses/strings and have found that if the tweeters were switched on on my Ashdown cabs they added more definition and modernness to the sound, however I prefer my high end in a more old school way, less sharp and precise so I leave them off.

[BassAdder60]

I too tend to prefer tweeters off but if I recall on my old Ashdown cabs it had three positions, off, low and high. I ran it either off or low 

 

I still do the same on my Ampeg cab as it adds a tiny bit of presence I feel but generally I’m a tweeter off guy 

[Bill Fitzmaurice]

I never slap and always use tweeters. However, mine are effective from 2kHz, so they operate nearly a full octave lower than average. The reason is that there's a lot of content in the 2kHz-4kHz range. While woofers for the most part have response in that region it's with very narrow dispersion. Tweeters have wide dispersion there, so I don't get the high frequency laser beam effect. Above 8kHz there's little I want, so I roll that off with my EQ. As to why commercial cabs have such a high crossover to tweeters, back when they were first introduced tweeters capable of going to 2kHz were both rare and expensive, so 3.5kHz to 4kHz capable tweeters were used. That practice should have ended back around the turn of the century, but it didn't. 

Edited October 18, 2023 by Bill Fitzmaurice

[Baloney Balderdash]

I never slap, but as my setup is an "amp-less" setup I make use a FRFR PA speaker when not going through a full PA system, which naturally got a tweeter (1.7" high mids/treble tweeter, 15" bass woofer/mids driver) to be able to reproduce the full frequency spectrum (and I do believe the crossover of the FRFR PA speaker that I use is at about 2kHz or so, referring to Bill Fitzmaurice post above this one).

 

However I also make use of an IR cab sim, but while that cab sim is actually also of a bass cab that does feature a tweeter, namely the Ampeg SVT 212AV, looking at the frequency response the high end roll off of that IR does start at about 5kHz, with an abrupt steep decline at about 7kHz, as well as the LPF of the IR loader I use is activated with a cut off point set to at just about 14kHz, so the really high treble content of my signal is reduced significantly anyway.

 

Having this expanded frequency range, compared to say a cab with a single 15" driver and no high frequency tweeter, results is a more natural/balanced, less bloated, tone, with more clarity and better definition, and a nice amount of snap and bite, but without it getting thin or shrill in any way.

 

Edited October 19, 2023 by Baloney Balderdash

[fretmeister]

I never used to use them. Either my cabs didn't have them or I turned them off.

 

But now I've got one in a Barefaced One10T and it sounds much better with it on. No brittle highs, just a more complex and pleasing tone even when I'm using flats on a P with the tone down a bit.

 

So, as per Bill's post ^, I suspect my past cabs just weren't as well designed.

[BigRedX]

Depends entirely on the cab design and what sort of bass sounds I'm favouring whether or not I need tweeters.

 

I did briefly own a TE Bright Box in the early 90s - for the length of time it took to pay for it, get it home, plug it into my rig, discover that it made zero difference to the sound I was using at the time, and take it back to the shop for a refund.

[PaulWarning]

my Fender V2 cabs have a tweeter rocker switch to select off, full or -6db, I have them off, sometimes they get moved accidently, I never notice till I actually look at them, tweeters on bass cabs seem counter intuitive to me.

I never/can't/ don't want to, play slap and use DR neon strings which are quite bright

[Chienmortbb]

@Bill Fitzmaurice summed it up pretty well. Anything in the 2-8KHz region is best served by a tweeter, as beaming of 10-15" drivers mean the only people that hear the sound of the bass are straight in front of it. If that is the bassist's backside, it's all lost. A well-designed cab with a tweeter will not sound harsh, and cabs cannot hiss, only amps and pedals can hiss.

 

Any bass will sound better through a properly designed cabinet. IMHO, cabinets should be substantially flat and if I want a particular sound I use EQ and/or pedals. This is true when using all types of basses, flats or round wounds.

Edited October 19, 2023 by Chienmortbb

[Woodinblack]

I want my speaker to do as little colouring as it can and just put out what the amp gives out. if I want muffled I will do that at the amp.

[chris_b]

I play basses with flats, zingy rounds and dead rounds.

 

I always have my tweeters at about 2/3rds. If the tweeter is picking up any frequencies from the basses, I want to hear it. Whatever the signal a tweeter is not going to sound bad so, even if it's only for general ambience, I'll use it.

[ahpook]

14 hours ago, BassAdder60 said:

I too tend to prefer tweeters off but if I recall on my old Ashdown cabs it had three positions, off, low and high. I ran it either off or low 

 

I still do the same on my Ampeg cab as it adds a tiny bit of presence I feel but generally I’m a tweeter off guy 

 

Yep, me too, I just prefer the sound of tweeter-less cabs. I like clank, but not like that.

[Phil Starr]

Completely with Bill here, tweeters in bass cabs are for midrange mainly. The trouble is that few designs take a lot of care over this and certainly on mid-price cabs the tweeter isn't properly integrated into the design and is compromised by commercial decisions.

 

You need rigid and fairly heavy cones to produce loud bass. Moving these back and forth quickly enough to make sound at high frequencies isn't really possible and above certain frequencies the outside of the cone lags behind the movement of the coil and the cone starts to flex and the sound starts to distort and you can see this in the frequency response also, most bass speakers show peaks and dips in response above 1khz. Speakers reduce in output from the side once the diameter of the speaker approaches half the wavelength. If you sit at right angles to the speaker the sound from the nearest part of the cone arrives at your ears before the sound from the far side and the delay causes cancellation. By the time the sound reaches you from the far side the cone has reversed direction. you can see all this in the driver manufacturers data. this is the Faital 12PR320

 

 

You can see the cone starting to flex at 1kHz in the blue line and also (red line) how much less output there is of axis due to cancellation. Between 2k and 7kHz its down between 12 and 24db so that's almost all the top end of the bass lost at 45 degrees to the side.

 

The trouble is a decent horn/driver and crossover add considerably to the cost of a cab and may cost as much as the bass driver, adding roughly a third to the materials cost of the cab. Early designs were also developed with very little science behind them. Crossovers are often little more than a high pass filter often a single component to protect the tweeter so a lot of high end is added to the midrange peak that you already have and you can see on the graph. Since you have the tweeter and woofer operating at the same time there are also a whole set of new peaks and troughs and off axis issues. Lower crossover frequencies also mean more expensive drivers so they are 'crossed over ' too high and not sharply enough and what you end up with is that horrible tizz that everyone hates.

 

Even worse is the piezo tweeter which can be wired with no crossover at all and almost inevitably sounds awful. Not a surprise, they are only £2.50 retail.

 

So properly engineered tweeters should be concentrated on improving the mid-range and directionality of the speaker cab. they should give you cleaner smoother midrange and better intelligibility on stage. too many are just added because you 'need' one to appeal to a bigger market.

 

 

[Lozz196]

I keep thinking of one of @stevies cabs, given back issues a single good cab seems the way to go and the off-axis projection of these appears to be much better than anything else around.

[stevie]

Here's the frequency response of a 2x12 +horn bass cab from a respected US manufacturer. The red line looks fairly good, almost FRFR in fact, but you'll only ever hear that if your head is right in front of the cab. Move to the side or above and what you hear is shown in the off-axis curves - huge suckouts in the upper midrange! This is the main reason players complain they can't hear their bass clearly when playing live. You can see the tweeter coming in at around 5kHz to provide the boom-tizz sound we know and love. 😀 It's hardly surprising so many players switch them off.

 

The solution (in a two-way system), as @Bill Fitzmaurice has pointed out, is a proper compression driver crossing over at about 2kHz or lower. With a carefully designed crossover, you can get a nice, smooth frequency respose that slopes gently towards the higher frequencies as you move off axis and counteracts the bass driver's tendency to die above 1kHz. The result a much more natural sound.

 

Bassists playing through PA cabs already know what I'm talking about. Unfortunately, I can count on the fingers of one hand the number of dedicated bass guitar cabs using this approach.

Edited October 19, 2023 by stevie

[Jean-Luc Pickguard]

Thanks for all the responses people. I'm beginning to think that my prior dismissal of tweeters may have been somewhat misguided, and the tweeter being switched in may have contributed to how much I liked the tone I was getting. I wasn't enjoying the amount of hiss coming from the cab so I will have to figure out how to eq as much of that out without negatively impacting the tone. I'll have to turn up early to rehearsal so I can investigate further.

[Bill Fitzmaurice]

2 hours ago, Phil Starr said:

Even worse is the piezo tweeter which can be wired with no crossover at all and almost inevitably sounds awful. Not a surprise, they are only £2.50 retail.

Piezos can sound very good, when correctly employed. The trouble is I've never seen them properly employed in commercial cabs. I run them down to 2kHz at high output with very low distortion. But even in a 1x10 I never use fewer than six of them, and only with a real crossover.

[MrDinsdale]

I really like the Baer ML cab which has a 6” mid driver instead of a typical tweeter, never gets overly hissy and cuts through great. Just need a second to cut through with our obscenely loud drummer. I do also have a LPF on my Capo preamp enabled though.

 

I also loved the Barefaced cabs with tweeters, again just sounded clear without being shrill even with distortion. The EBS and Ashdown cabs I’ve used at rehearsal pretty much always have them set at the lowest setting though. 

[Rob Bisby]

I have the horn all the way off on my barefaced big baby 2 for my band, just think it sounds better 

[Wolverinebass]

On my Vanderkley 2x12 the tweeter is always on maximum. Not because I slap like Mark King, but just because I like the cut you can get with it. It's basically so nothing of the signal is cut. So basically the DI you hear (post fx or not) is more or less the same as what comes out the speakers.

[Jean-Luc Pickguard]

I had rehearsal this evening so I checked how the tweeter switch was set on the back of the cab and I was surprised that it was actually off! Taking my pedalboard out of the equation and plugging the bass straight in totally eliminated the hiss. I suspect the boss LMB3 was causing the issue, but I'll need to investigate further.