If you're building a tall three-way speaker and your midrange driver is closer to your seated listening axis than your tweeter should you go with that and tune the crossover on the midrange axis? Or should you swap the midrange/tweeter locations?
As I understand it both configurations can be made to behave similar if the x-over is managed properly for both. More interesting is perhaps the impact of diffraction from the cabinet. Here distance from transducers to edges matters and is not possible to fix with X-over. Also, hight for midrange might be the most sensitive so depending on the rest of the baffle configuration/dimension, this might effect the mid/tweet positioning. TM or MT don't matter I think as an isolated problem - the culprit is that it can never be an isolated problem 😉 so - go with it!
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1. If you're in the building stage, it is best to optimise driver placement while you can. Assuming that you have a flat baffle, you can start by placing the mid and tweeter close together so as to minimise the difference in acoustic path length. (One can use a sloped, stepped or curved baffle, too).
2. Have a look at the "spinorama" method of speaker measurement and subsequent crossover design (VituixCAD 2) to help you visualise and optimise your speaker's radiation pattern.
2. Have a look at the "spinorama" method of speaker measurement and subsequent crossover design (VituixCAD 2) to help you visualise and optimise your speaker's radiation pattern.
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It depends on your tweeter, if you are using like a ribbon tweeter with limited vertical dispersion then you want it to be at ear height
The important thing is to decide on a design axis and stick with it. The tweeter axis is usually chosen, but in my recent builds I have used a point midway between the tweeter and midrange. If your mid and tweeter are close together, it would be reasonable to use the midrange axis.
This design axis, once you have selected it, will serve as the starting point (reference) for all your subsequent horizontal and vertical polar measurements. You will use it for both simulation and for system level measurements. I break with convention here because I also use it for my gated far field measurements of tweeter and midrange. Not only do I select a design axis, I also select a design reference distance. Many experts advise us to make gated far field measurements of each driver using that drivers individual axis, and import that response into the simulation.
j.
This design axis, once you have selected it, will serve as the starting point (reference) for all your subsequent horizontal and vertical polar measurements. You will use it for both simulation and for system level measurements. I break with convention here because I also use it for my gated far field measurements of tweeter and midrange. Not only do I select a design axis, I also select a design reference distance. Many experts advise us to make gated far field measurements of each driver using that drivers individual axis, and import that response into the simulation.
j.
TNT, Shaun, celef, hifijim,
Thanks for your input. I've done a bunch of gated measurements outdoors with REW on different listening axis. I'm using a Hypex DLCP crossover which has allowed me to quickly try different topologies. What I've noticed is that if the tweeter is more than 2 inches above the listening axis my attention is drawn up to it while listening to music. Is this normal for "tall" speakers? It feels unnatural.
Thanks for your input. I've done a bunch of gated measurements outdoors with REW on different listening axis. I'm using a Hypex DLCP crossover which has allowed me to quickly try different topologies. What I've noticed is that if the tweeter is more than 2 inches above the listening axis my attention is drawn up to it while listening to music. Is this normal for "tall" speakers? It feels unnatural.
You hear what you hear. I am not that sensitive to tweeter height, but clearly you are. The joy of DIY speakers is that you can design and build what is right for you in your room.
2 inches is small to have such a noticeable effect, especially since we are least sensitive to elevation compared to left/right bias. However, it would depend on the tweeter itself (its radiation pattern), as well as the crossover frequency.
FWIW, I have in the past designed speakers and crossovers according to fairly good design principles - essentially crossing over to the next higher-bandwidth driver before the lower driver begins to beam, while taking care not to use a driver in the lower frequency regions where its distortion begins to rise. (That, plus optimum baffle placement to minimise diffraction effects). But since then, "Spinorama" has been the best thing since sliced bread. I can't recommend it enough.
FWIW, I have in the past designed speakers and crossovers according to fairly good design principles - essentially crossing over to the next higher-bandwidth driver before the lower driver begins to beam, while taking care not to use a driver in the lower frequency regions where its distortion begins to rise. (That, plus optimum baffle placement to minimise diffraction effects). But since then, "Spinorama" has been the best thing since sliced bread. I can't recommend it enough.
Thanks for the Spinorama suggestion. I've been reading about it today. It looks like a really useful model.