If my speaker is only rated to 45hz do I need a HPF to tighten up my B string?

The problem may be because you are mixing dissimilar designs.

AFAIK the Wizzy 10 is a reflex cab and the M-line is a transmission line. If these cabs have drastically difference phase and group delay characteristics they may fight with each other, rather than summing perfectly.

I suggest you try each cab by itself. You may get less volume and lows, but the sound may improve. Ideally you want a pair of identical cabs...or at least cabs that have compatible tunings.

I do know that an HPF can help a reflex cab. All basic ported/reflex designs have sort of an "S" shaped excursion plot. Here is an example from the cab design document for the Eminence Deltalite 2512.


The 2512 is rated for 250RMS, but notice this particular design only has 125W of mechanical power handling below 100hz. Also it requires a steep HPF set to 35hz.

Notice that excursion increases below about 500hz. Excursion peaks around 70hz and then starts to decrease. The reason is when the port starts becoming active it suppresses driver excursion. (Fb) port tuning is 44hz and Xmax is 4.9mm. Notice that excursion dips at 44hz and then picks up quickly as the frequency goes lower. The excursion line turns from black to gray at 35hz. This is where the driver hit's Xmax with 125W. With the HPF applied, the signal will be attenuated by 3dB at 35hz. A 3db change essentially means the power has been cut in half (125/2=62.5W), which keeps driver excursion below Xmax.

Below Fb output of a ported design tends to drop off quickly. So excursion is increasing and response is decreasing.

Here is the response plot for this design:


Notice how low the output is at 35hz compared to 100hz. Usable response is frequently defined as the point where output is down -10dB. The graphs shows almost 120dB at 100hz, but only about 105dB at 35hz. After you apply the 3dB cut for the HPF the response will be down to 102dB. So IMHO there is probably not really enough output at 35hz to be considered usable. AFAIK this is the raw response plot without the HPF applied. With the HPF, the low frequency cutoff will become steeper at 35hz.

I don't know how EA rates the low frequency cutoff, but I would not be surprised if 45hz is the point where the cabs are down by -10dB.

I do think an HPF would be good idea if you plan to push these cabs hard with heavy lows. In my experience, an HPF will tend to make the lows tighter and more clear/focused. These are qualities I like, but some prefer big pillow lows that are sort of loose and woolly. In some instances an HPF can also make it sound like there are more lows, but in my experience it tends to be very subtle.

With the HPF, the driver is able to work better in it's intended pass band, because it is not flopping around like crazy trying to produce super low frequencies.

Anyway you can try an HPF before you buy?

 

In my experience,
if you're after a tight low end and don't like muddy sound, a HPF will do wonders for you.
Some units have HPF in place without advertising it too much, like the Sansamp pedals
or some amp heads.
I usually use a HPF unit with adjustable cutoff frequency and just set it to 'wide open', then
turn it up while playing low.
To my ears and with my gear, I can discern between unwanted mud and much wanted lows.
I turn the knob until it starts cutting wanted lows, then back off a bit and I'm done.

 

Does cutting the Low EQ on your Doubler tighten up your B string?

If the answer is "yes" then an adjustable HPF will allow you to cut low frequencies even more surgically and precisely.

You could even do the classic boost/cut studio trick where you boost the Low EQ but then cut the low-lows with the HPF.

 

The speakers on paper is one thing. An important question is, how well does your amp actually reproduce 45Hz. Maybe it’s already rolling that off to some extent. A phone app spectrum analyzer can give you a rough picture of what’s going on.

 

In the meantime you can follow his suggestion to try each cabinet separately. If they each sound good alone, then the problem would seem to be simply that they don't get along well with each other and you need to replace one or the other. In that case no pedal will help.

 

What does the notch filter do on your amp ? I see it goes to 50Hz . Maybe this would do what you need. You could try it .

 

The curve posted above (to an Acoustical Engineer) says it all. If you play notes low on your bass, the speaker will move a lot, but not really put out much sound at the fundamental of the note. This is not something odd in your speaker - the desire for light and loud means that almost every commercially available bass guitar cabinet has this shortcoming.

If you do play without a high pass filter (there is one in your amp, but it may not be enough), and play low notes at relatively high volume, the speaker's excursion (it's movement) will go past where it's "linear" - it goes past where it operates cleanly. At that point, it starts generating a bunch of harmonics. If you're playing a low E (41 Hz), it'll put out 82 Hz, 123Hz, etc. Those first two harmonics will sound OK, as will the 4x and 6x - they're "musical" overtones of the note you want to hear. But higher up - at 5x and especially at 7x the fundamental, you get into very non-musical territory. 7 times 41Hz is 287Hz, which is also in the area that we perceive as "mud" if there's too much. Contrary to popular belief, it's not the 41 Hz that's "mud", it's the non-musical overtones that result from driving the speaker too hard at low frequencies that is the "mud" that a high pass filter cleans up. If you ever get a chance to play through a clean, well set up (that's important) high powered PA with good subs, you can get a lot of 41Hz, and not have it sound at all muddy. It'll sound solid, and have a lot of impact.

So, a high pass filter is the cure for mud, but not for the reason most folks around these parts think it is.

 

Using a HPF has been a game changer for me. Having a hard cut off of all frequencies below a selected frequency has been far more effective than simply cutting at a certain frequency. My little Walkabout combo works much more efficiently - and I still get all the low end I could possibly want (or use).

 

HPF can be nice - I've used it mostly to tame the sometimes raging low end from the piezo pickups on upright basses.
For the best articulation with a low B string on electric bass, the most helpful thing I've found is to use the bridge pickup (assuming the bass has one). Even the best low B axes I've tried benefit from at least some bridge blended in and even my weakest 5-string can growl out in that register when I solo that pickup. (Bit of an extreme measure for me - 100% bridge is not my thing normally.)
HTH

 

The HPF on my Mesa was a real game changer for me. It allowed me to cut out unwanted boominess and maintain clear, tight focused bottom end of the B string. In short, it helped make it sound less muddy, and more articulate, better than attenuating the bass frequency on the head.

 

Might the problem be the room? In my practice room, I've resonance at around b flat (I'm using a four string).

 

The reality is that with our instruments most of what we hear is actually the 1st octave harmonic, not the fundamental. 40 hz is REALLY low and 30.87 hz is REALLY REALLY low. I set my HPF by ear, but I don't have any problem setting an HPF on a PA to somewhere in the 50-55 Hz range...there's just not that much content below that and it really frees up the amplifier watts to reproduce what actually IS there while simultaneously protecting against over-excursion of the drivers.

 

I always use an always on HPF for any head and for any cabinet. Besides cleaning up the lows, it helps keep your speakers safe. One of the best bass tools IMHO and even better with a compressor.

 

It's not just whether you can hear the lows (due to speaker response), but that your amp is still trying to make them and thus eating up valuable headroom. Remove those sub lows with an HPF and there will be more "room" for the lows you want.

 

Amateur/enthusiast here, but from all the Mixing Bass videos I've seen and tried on my personal rig and recordings, HPF and compression are essential to a "profesional" sounding low end. You can turn the bass' volume higher without creating a mess in the room/mix and risk damaging speakers.

I personally set a HPF at 72-80 Hz and boost bass if needed or move the HPF further down or up. Also from experience I would advice using a HPF on smaller and or lower powered combos/rigs to leave more headroom and squeeze a bit more performance out of the equipment.

 

Outbush,

The original Doubler has a single adjustable HPF (a trimpot accessed from the top of the amp, frequency range not specified) and the later Doubler II head has one on each channel with a 3-way switch (25 hZ (factory setting), 50hZ or 80hZ). So no need to buy an external HPF just yet

Check the manual for details and experiment!

 

No, higher the frequency roll off, the tighter the low end will be.

 

Apologies in advance if my question is slightly off topic. My cab (a Markbass NY122) has a frequency response of 45Hz-20kHz. How does it manage to reproduce a low E at 41Hz? And would a cab rated, say, 35Hz-20kHz, be truer to what an open E string sounds like and hence sound better?

PS. I asked this question a while ago in another forum but I'm not sure I understood the answer.