Are modern fullrange drivers better than tweeters?

[planet10]

That will be interesting.

dave

 

[Lawnboy]

About fifteen years ago, some PHD student in Florida published an interesting paper that indicated that listeners couldn't easily discern between stereo tweeters and mono tweeters.

IE - you can have ONE mono tweeter in the center of two stereo speakers and people couldn't easily tell the difference.

If you think about it, this makes a lot of sense.

First off, when you have stereo speakers radiating 10khz, even the tiniest amount of offset will generate comb filtering. 10khz is 3.4cm long, which means that if you move your head just 1.7cm (0.675"), the radiation from the left speaker will cancel out the radiation from the right speaker.

The other issue is that our perception of where high frequency sounds are located is determine by frequency response, not phase. If the left speaker is 3dB louder at 10khz than the right speaker, our perception of where those sounds are coming from will veer to the left. But as noted above, simply sitting an inch or two off-center will screw up that frequency response.

Put all of that together, and you can see why a single mono tweeter may be ideal. Or if not ideal, it sounds comparable to a set of stereo tweeters.

I tried this years ago in my car stereo, and was surprised by how convincing it was.

I remember reading that in diyma 👍🏼👍🏼

 

[Bryguy]

Yes, crossovers are evil. But the lower you can put them the better, under 400 Hz, and if the centre-to-centre is less than a quarter-wave at the XO frequency, the more of the evil you shed. Hard to do but if you can achieve that and a first order XO (not easy), they can almost disappear.

dave

Hello! I have seen you mention this 400Hz and below crossover point being ideal for WAW many times on this site. May I ask how you arrived at this conclusion? What, for example, makes a 400Hz crossover point, in your opinion, preferable to say, a 600Hz crossover point? Does it primarily come down to the fact that 600Hz is apart of the "critical bandwidth" as you have put it?

 

[planet10]

The number one criteria is being able to get the woofers and midTweeter within a quarter wavelength at the XO frequency. This places the drivers essentially conncident, so one gets the benefits of a coax without most or all of the time issues eliminated.

Add to that the need to consider the capabilities of the woofers & the midTweeter, how loud you need to play — move the XO up you can play louder usually.

dave

 

[Bryguy]

The number one criteria is being able to get the woofers and midTweeter within a quarter wavelength at the XO frequency. This places the drivers essentially conncident, so one gets the benefits of a coax without most or all of the time issues eliminated.

Add to that the need to consider the capabilities of the woofers & the midTweeter, how loud you need to play — move the XO up you can play louder usually.

dave

Understood. Thank you. The midtweet I'm playing with is quite small, with only a 14.5cm^2 Sd, so I thought I should probably set the crossover higher if possible. At 600Hz I still maintain 1/4 wavelength CTC spacing with the woofer I'm working with, so I thought it would be ok, but I remembered your posts about how you like to stick below 400Hz, so I thought I'd reach out in case there were important considerations I was neglecting to factor in. Again, thank you for your response

 

[cracked case]

Isn't it also an idea to crossover at the baffle step frequency, and well away from the resonant frequency of the full range?
Also if you can cross over bellow the resonant frequency of the cabinet, the big heavy bass cone shouldn't excite the panels.
You can kill a lot of birds with one stone with a WAW, the only real drawback is the large value components in the crossover.

 

[planet10]

Isn't it also an idea to crossover at the baffle step frequency

Yes, that is something to consider.

dave

 

[AllenB]

Isn't it also an idea to crossover at the baffle step frequency

Crossing at the baffle step isn't essential but it's a good opportunity.

Normally you pad a tweeter. Crossing at the baffle step gives you some freedom since you can use the FR at it's full sensitivity because you don't need to take it down 6dB.. so you can use one that's lower in sensitivity or, you can choose woofers that keep up with it.