That is agreeable. To low would show signs of non linear distortion. I think we have already dissected that issue. 200hz XO may have been pushing the limits as far as Linear Transient performance was concerned. Was never an issue for average spl. Raising the XO only increases headroom. At 220hz summing is still fine to my ears. I do not like the height of the tweeter but I will work on getting it lower plus I grow use to it over time. The major change has been the room. I went from a small living room with a loudspeaker placed away from walls to this corner loaded situation and it is Not the same. The difference in off axis character may be really showing its self in this situation. I am still tweaking things but the bass seems heavy regardless looking to be voiced flat....I keep giving my microphone the side eye, as the flat measurements do not seem to line up with perception, but it we've talked about how decay affects perception so I cannot say I should be shocked.... Whats really confusing is that if I measure levels right at the drivers, its obvious the woofers are at a much higher level than the tweeter, if I match levels this way, it sounds more balanced, but when taking measurements at the listening spot, it looks bass shy.... and then if I flatten things out at the listening spot, no it seems like its bass heavy. a work in progress....
Heres now
Heres the previous testing upstairs. (ignore the HF roll off justy a quick voicing to see cross band)
I had the system voiced flat for most of the testing, upstairs, but this is what I have.... Below is shot of the just horn when it was upstairs.
Either way, things are much dryer down here.... until the rom modes kick in.
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Camplo is still considering crossing the high frequency driver at 220Hz.
Two years ago, a few weeks after we were discussing SPL (your own hand clap reaching 125dB peak, etc.) you posted this graph showing at 220Hz, the high frequency horn/driver's second harmonic distortion is -22dB from the 110dB fundamental, ~8% distortion.
As I recall, you still decided that was enough for your revised design goals, though one decent front loaded 15" would easily have +20dB more output with less distortion at that SPL level.
I still think the IMD of a HF compression driver forced to cover two decades of bandwidth at anything approaching live acoustic instrument peak SPL sounds terrible compared to what it sounds like if the cone drivers below "take the weight off".
Art
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@weltersys Thank yo for debating me, I do appreciate it.
We also had the discussion surrounding incorrect thd measurements of horns due to low level like that in the cutoff. That measurement was also 3db above target. It does have the actual 220hz response
I wanted to reach 115db per channel, it made sense. As the challenges unfolded I started back off. Maybe 115db accumulated would be good enough, I said. That only requires 112db from the each channel approximately. I also starting investing gating thd taken without the horn but with appropriate voltage. I think the pic below is near 3volts... Putting max linear performance closer to 110db. per channel... to which then I said... well 95db is max safe average....plus 15db 110db walla. I only care about 1meter listening as it is.
Moving forward I still wanted to try and get to the goal anyway. I mean maybe I would like it or it would make a real world difference, consider that I concluded no real world deficit with the original arrangement.
Lately Ive been working here. Effectively crossing somewhere around 280hz or so. I'm still learning the proper terminology. Even though my filter is much lower, the effective roll off and knee is much higher.
Here there is likely no issues with headroom, given the size of the horn and lf extension of the driver.
Right now I am baffled by what my measurements show versus what I hear... possibly my kids goofed my measurement mic, then I looked at prices of the umik-2 and thought, maybe I better make sure lol...
You guys know a sure fire way of testing a measurement mic?
We also had the discussion surrounding incorrect thd measurements of horns due to low level like that in the cutoff. That measurement was also 3db above target. It does have the actual 220hz response
I wanted to reach 115db per channel, it made sense. As the challenges unfolded I started back off. Maybe 115db accumulated would be good enough, I said. That only requires 112db from the each channel approximately. I also starting investing gating thd taken without the horn but with appropriate voltage. I think the pic below is near 3volts... Putting max linear performance closer to 110db. per channel... to which then I said... well 95db is max safe average....plus 15db 110db walla. I only care about 1meter listening as it is.
Moving forward I still wanted to try and get to the goal anyway. I mean maybe I would like it or it would make a real world difference, consider that I concluded no real world deficit with the original arrangement.
Lately Ive been working here. Effectively crossing somewhere around 280hz or so. I'm still learning the proper terminology. Even though my filter is much lower, the effective roll off and knee is much higher.
Here there is likely no issues with headroom, given the size of the horn and lf extension of the driver.
Right now I am baffled by what my measurements show versus what I hear... possibly my kids goofed my measurement mic, then I looked at prices of the umik-2 and thought, maybe I better make sure lol...
You guys know a sure fire way of testing a measurement mic?
I agree that in sound reinforcement, there are better choices than using a compression driver very low at peak SPL, although there are drivers that can handle a low crossover point. And I am familiar with your extensive experience in this field and certainly respect that. For modest SPL like audio at home it is no problem to cross the CD low if that brings benefits.
Could you repost the above graph with higher resolution spl scale, please? It will be more revealing to see what happens. And smoothing no more than 1/6th, preferably 1/12th?