Speaker selection for single ended amp

[Dinolobe]

The impedance peak you are referring to is a characteristic of the drivers. It is an indication of the natural resonance frequency, due to mechanical/acoustic/electrical properties.

There are ways to alleviate it electrically. Here is a link to a paper by the late Marshall Leach that derives a circuit to accomplish it. It should be noted that inductor and capacitor values get larger for lower frequencies. (often cost prohibitive) Also, this is applicable to a single peak (e.g. sealed box), but not for the two peaks resulting from a ported box.
https://leachlegacy.ece.gatech.edu/ece4445/downloads/zobel.pdf

Thanks for the link ! I’ll have to focus a bit on those equations in order to understand them correctly, but it seems that this circuit would be of good use with the kind of speakers I would like to build !

 

[knarfor]

I’ve re read the thread and realized that a solution has been pointed out : using series crossover. I’ll need to investigate this, but is there any other way to thame those big impedance bumps ?

I’m just thinking out loud, but wouldn’t those peaks cancel out themselves if they were 180 degree out phase from each other ? My understanding is that phase should be as close as possible to 0, so a 180 degree phase out should definitely affect the sound. I just don’t have the knowledge to completely understand the effect of phase on the sound. Could there be a way to use phase to cancel out those peaks from the amp point of view while still getting "in phase" sound out of the speakers ?

Thanks for your helpful answers guys !

Stewart Hegeman designed an enclosure that used a series of 1/4 wave tubes to acoustically tame his speakers' impedance bumps. I attached articles by Cornelius Morton describing their design. You should be able to download them from my DropBox. Links here:

The main article:
Dropbox - 1203morton.pdf - Simplify your life

The follow up:
Dropbox - 0209morton.pdf - Simplify your life