I have this idea of adding either heavy duty pot to a crossover for the adjustment of a tweeter in a crossover or at least a switch that would adjust tweeter level. The tweeter is 10 DB more efficient than the woofer so I am betting that there could be some latitude here. As it sits now, the tweeter is padded down by 10 DB. It is a 2-way crossover with a 2nd order Butterworth slope at 2.5 Khz. The woofer is a Mark Audio 12PW used in a loaded horn design, and the tweeter is a Scan Speak horn loaded tweeter. I will have to look at the model number. I bought it from Madisound for about $42 ea.
I would actually like to tip up the tweeter level just because it might help me and my old ears but then maybe a bad idea. You guys will certainly have valuable advice. Thanks.
I would actually like to tip up the tweeter level just because it might help me and my old ears but then maybe a bad idea. You guys will certainly have valuable advice. Thanks.
Without seeing the crossover schematic, it's hard to give decent advice.
If the crossover currently includes a fixed L-pad that uses standard values and the tweeter is 8 ohm, you should be able to change to an adjustable L-pad with little impact to the crossover. 4 ohm L-pads can be hard to find.
And "padding down" a tweeter isn't always done with a standard L-pad configuration or with typical values. There's lots of latitude in how this can be accomplished.
If the crossover currently includes a fixed L-pad that uses standard values and the tweeter is 8 ohm, you should be able to change to an adjustable L-pad with little impact to the crossover. 4 ohm L-pads can be hard to find.
And "padding down" a tweeter isn't always done with a standard L-pad configuration or with typical values. There's lots of latitude in how this can be accomplished.
Reasonable request for the crossover. And I also appreciate the reference the other thread. I will get right on it.
Let me add that I bet it would be easier for a switch to be installed with maybe 3 positions.
Let me add that I bet it would be easier for a switch to be installed with maybe 3 positions.
Using an equaliser is another option.. even a temporary one while you find the problem. Using the crossover to change the 'voicing' is fine and it can be done without altering the crossover proper (the acoustic blend) when done with care, but that's what you could accidentally change.
That is likely to be a Scanspeak H2606/920000 which has a nominal impedance of 6 ohm and a sensitivity of 95 dB/2.83V/1m.
To attenuate a 6 ohm tweeter by 10 dB as you have stated, the L pad should have R series = 3.9 ohm and R parallel = 2.7 ohm.
To tip the tweeter UP by 3 dB, you would need Rs = 3.3 ohm and Rp = 4.7 ohm.
I hope that helps you see how the resistors must change in order to suit the degree of attenuation required.
You got it! Thanks. Yes, in fact it is 6 ohm (I forgot) and I am thinking to go with a switchable choice between '0 DB and +3DB' as you have stated.
Thanks guys for a start using this idea. I actually would prefer using a switch instead of potentiometer for this. FWIW, I really don't want to decrease the tweeter so much as to have a normal and plus setting available.
Thanks guys for a start using this idea. I actually would prefer using a switch instead of potentiometer for this. FWIW, I really don't want to decrease the tweeter so much as to have a normal and plus setting available.
Assuming that the series resistor in your L pad is the 3.3 ohm one and the parallel (shunt to ground) resistance is the 2.2 ohm one, then you could try this:
Devise a method of switching an additional resistor of 2.2 ohm in series with the existing 2.2 ohm resistor to increase the parallel resistance to 4.4 ohm - which will give you a 3 dB lift.
Devise a method of switching an additional resistor of 2.2 ohm in series with the existing 2.2 ohm resistor to increase the parallel resistance to 4.4 ohm - which will give you a 3 dB lift.
1) Is a bucking magnet something that is added to the tweeter magnet?
2) The sengpielaudio calculator only does attenuation? I need the opposite, but I think that I have the values to work with now.
2) The sengpielaudio calculator only does attenuation? I need the opposite, but I think that I have the values to work with now.
That is the calculator I used in post #7 to find the resistor values relating to the two required degrees of attenuation (10 dB and 7 dB) of the 6 ohm tweeter.
The calculator gives the theoretical value of each resistor, but the nearest standard value of resistor is what is used in practice.
@Ixnay
a bucking magnet can be added to any driver with ferrite magnet.
The magnet can take away 1 - 1.5 db using a same size magnet and glue it to the existing magnet with adhesion.
The magnet can give 1 - 1.5 db more efficiency with a same size magnet and glued to the existing magnet opposing the force.
Just take care to buy the right ringmagnet for loudspeaker use. And read about using the glue as fixation is not that easy if the glue is used wrong.
a bucking magnet can be added to any driver with ferrite magnet.
The magnet can take away 1 - 1.5 db using a same size magnet and glue it to the existing magnet with adhesion.
The magnet can give 1 - 1.5 db more efficiency with a same size magnet and glued to the existing magnet opposing the force.
Just take care to buy the right ringmagnet for loudspeaker use. And read about using the glue as fixation is not that easy if the glue is used wrong.
I have messed around with big magnets in the shop before, finding that they are stronger than I am, especially when I want position them in particular spot and they say no. And the good one is when you have a large magnet, yes, of course holding it with your fingers wrapped around it, and then get it close to that big metal plate where you think it should go. Don't fret, it is going there bro, just like your fingers behind it. Now you have two hands that are completely useless to you expect to produce sharp Lpain-Rpain.
I know with a tweeter I wouldn't even break a sweat. Still, as you mentioned it takes care to get what you are shooting for when it comes to placement.
On a lighter note, I just ordered the whole shebang from Parts Express. Resistors, switches and even level controls if in fact the experiment starts to go south and I want some kind of precise control.
I know with a tweeter I wouldn't even break a sweat. Still, as you mentioned it takes care to get what you are shooting for when it comes to placement.
On a lighter note, I just ordered the whole shebang from Parts Express. Resistors, switches and even level controls if in fact the experiment starts to go south and I want some kind of precise control.
Tipping up the entire tweeter range may not be the best approach.
Most "old ears" hearing declines above ~2kHz with age, with the very high frequencies (VHF) above 10kHz taking the biggest hit:
Reducing attenuation will raise the level above the crossover point across the entire range, which may "boost" frequencies you still hear fine.
You may want only more VHF, without raising the 2-5kHz range.
Since you are attenuating the HF, there is a potential to raise VHF by as much as that amount.
The Scanspeak H2606/920000 has a fairly flat on-axis response to ~16kHz, you could make it's upper response rise at +6dB per octave by inserting a smaller value capacitor (with the same or greater voltage) to bypass the attenuation.
For a 6ohm driver, using a 7mfd bypass capacitor would put the "lift" starting around 4kHz, a 3mfd bypass cap ~8kHz.
You could install an on/off switch to put response back to normal when younger ears are listening 😉
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