House Jam Micro Cab

[Chienmortbb]

2 hours ago, cbd said:

Is there any benefit to putting a capacitor in series with the speaker as a crude high pass filter? Just had a go on a crossover calculator website which reckons a 220uf bipolar would give you a 6db/octave cutoff at around 90Hz - that would cost about £2.50. Or would it have to be steeper than that to avoid taking too much off the higher frequencies?

To make a decent HPF at the driver end  mean big heavy and expensive components . You need IMHO something line 18-24dB. That entails a 3rd or 4th order filter. A first or even 2nd order filter ( 6-12dB) would putter cutoff frequency too high. 
 

As @Woodwind says it is easier to achieve in ghe signal path rather after the power stages. I think the Thumpinator sets the -3dB point too low although there are lots of them about. 
 

If you have WinISD, you can model the driver and then add various filters to see the effect on the low increase by adding higher order filters. 

[Phil Starr]

22 hours ago, cbd said:

Is there any benefit to putting a capacitor in series with the speaker as a crude high pass filter? Just had a go on a crossover calculator website which reckons a 220uf bipolar would give you a 6db/octave cutoff at around 90Hz - that would cost about £2.50. Or would it have to be steeper than that to avoid taking too much off the higher frequencies?

 

You almost certainly have a tone control which will roll off the bass by 12db or more. It would be easier to just use that as a starting point, not least because it costs you nothing and you can restore the system back to normal when that has finished. I don't want to speculate too much but anyone using the cab for the first time will sense the loss of the bottom frequencies and probably boost the bass on their amp or bass if it is active. We've all played with guitarists who swear blind that they haven't turned up even when you can see it on the meters. Bassists can be just as naughty

 

The thing is that it is perfectly acceptable to use a big amp with a small speaker if you are aware of all the parameters. As the owner of everything you know the risks and will be careful accordingly. For a bassist just jamming with their mates and no knowledge of the gear involved you'll just go for it. Just swapping from a bridge pup to a neck pup could be enbough to put you in the red zone.  At open mic nights I reckon I'd match my cabs double the amp power for 'safety' as you have no idea what fx or playing style you will come across.

Edited 13 hours ago by Phil Starr