Horn for Neo hot spot

[GM]

Hope you get to feeling better, I suffer from migraines that can immobilize me, so 'feel your pain'.

Anyway, if you design the BLH to cover the driver's rising response BW, then the higher the mass corner is the longer the horn's path-length must be for a given Fc and at some point the time lag between the horn's and driver's output becomes audible, 'smearing' their overlapping BW (acoustic XO).

Different folks have different thresholds for noticing and/or find this time 'smear' irritating, but a good rule-of-thumb (ROT) is to have the acoustic XO no higher than ~250-400 Hz depending on how sensitive the listeners are to it, ergo ideally its effective mass corner will be the same. Since I fall into the < ~250 Hz group, this driver is unacceptable to me and if you have a variety of listeners, then best IMO to err on the low side of caution when choosing an effective mass corner.

It's this latter criteria that gets many folks into trouble, i.e. they design a BLH based on its T/S specs, then drive it with a high output impedance that's significantly increased Qes, lowering the mass corner, so the whole horn is now too small.

GM

[brsanko]

According to hornresp the XO would be at about 350hz, is this inacurate?

[GM]

I haven't inputted your design or messed with the CH option yet, but the deep notch appears to be at ~400 Hz in the shadow response plot.

GM

[brsanko]

Ok I see what you mean. I guess I haven't listened to any designs with the crossover that high so I have no idea if it would bother me or not. It's just such a small easy to build design it's so tempting, But if the drivers aren't going to work at all in a horn design if I don't like it that's $80 down the drain. Hmm what to do. Do you think the effect would be less bothersome in a rear and surround speaker?

[GM]

Don't know for sure, but due to the fact that when properly set up the sum of all the surround channels should = one main's output, then surround effects will be at least -3 dB (half power) in amplitude, so you're going to be concentrating on the mains output and more importantly, the video, which causes your brain to 'hear' what you're seeing.

Factor in that surrounds act as one only for LFE special effects AFAIK and I doubt anyone would notice it even if it was in our most acute hearing BW. I mean our internal processor can compensate for gross timing errors (or create them) when sight is added to the 'mix'.

Listening to 5.1 music without the video is an altogether different matter since we have to reconstruct the event using only a heavily processed recording of it played back through a typically high distortion system if other than headphones. Indeed, it's the various distortions that gives us the 'flavor' of the event, so it's a fine line between 'Heaven' and 'Hell', ergo 'God' is in the balance of the details and just like with religion there's no one true one for everybody.

GM

[gychang]

interesting design if the math/physics work out.

gychang