Loudspeaker EQ

I am preparing to hard wire in some of my mods to the GX300's. I'll probably make the 2R2 on LF switchable, perhaps with an extra cut option for late night listening. The MF boost switching is rarely used to I'll probably just keep the +2dB option as a midrange spotlight but I have been enjoying a lower MF crossover so may add this as a switching option. On the tweeter I do occasionally use the -2dB teble cut and am thinking about a similar boost by switching out the stock resistor.

Today I tried out a lot of the options in order to find which ones were interesting and listenable with the right material. Other options were either inaudible or not to my liking.

 

Now an interesting finding: you can make a simple tone control using your loudspeakers, essentially a 'tilt' control where you subtly alter the balance of bass and treble extremes. Please don't try this if your amp's manual has warnings about speaker connections or you are nervous about breaking something by getting the wiring wrong.

I am assuming the speakers have separate LF and HF terminals and you normally link these together.

Please leave the link between the black or minus terminals in place and take out the red or positive link. You may wish to lower the volume on the amplifier first or put on standby if it is a valve amp. Check carefully that you are not shorting out the amplifier, the resistor should go where the link was between the two red/+ terminals. I take no responsibility if you do something silly or dangerous. If in doubt you shouldn't try this but take care and you may like the result.

Lets say you want to have more bass...

The opposite wiring approach applies for getting more treble than bass, the red+ plug on the cable from the amp goes to the HF+ terminal and the resistor joins this to the LF+ so there is less bass.

I did eventually rig up an A/B switching arrangement for that inductor feeding the midrange speaker. Very short cables which stayed in circuit but shorted out the new inductor.

I used a fixed position for a calibrated microphone and REW software to measure the frequency response and THD with and without. Miniscule difference, slighlty steeper rolloff and about 0.2% less THD. Which is probably inaudible. So I reverted to stock crossover, moved the test gear away, popped the inductors into one of my spares boxes, and then played more music which was nice.