Art, there's no significant difference in the FR between the two conditions. I just posted the FR curves.
@Brian,
Are you saying that the HR sim estimates 3db more output than my cab? I thought the 96db@35hz was ok? Again I haven't seen the HR sim since I haven't had time to get familiar with HR. Could you share the input parameters as a screen shot?
Anybody else but CRESCENDO with real half space measurements of a TH18?
I think I know where at least some of the impedance misreading in REW can be found. I have a suspicion that I forgot to include all cabling for the impedance calibration being the resistance of the test leads. I will try again next weekend.
Are you saying that the HR sim estimates 3db more output than my cab? I thought the 96db@35hz was ok? Again I haven't seen the HR sim since I haven't had time to get familiar with HR. Could you share the input parameters as a screen shot?
Anybody else but CRESCENDO with real half space measurements of a TH18?
I think I know where at least some of the impedance misreading in REW can be found. I have a suspicion that I forgot to include all cabling for the impedance calibration being the resistance of the test leads. I will try again next weekend.
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Hi Andy, I tried to line up your measured response with the calculated one as best as I could. HornResp's calculations assume no losses, so the expectation is that, at least in the passband, the measured response is likely to be a bit lower than the HornResp prediction, how low being dependent on how "lossy" the build actually is (proper sealing and bracing will minimize these losses).
OTOH, you may see some gain at some frequencies, due to things like directivity due to the frontal size of the box.
IMO the issue with the impedance readings should be of more concern, because of that fairly large difference at the impedance minima.
Attachments
The REW file I posted is 2pi. The dip can be eliminated by adjusting the gate on the impulse response, I just cut the first few ms off with the gate accidentally. You can open the file and adjust the gate and all is well.
I wanna know where you can use a system like that and not have to worry about noise complaints. A pair of 18" THs in a room that big isn't sane.
Rather jealous.
Chris
We only really cranked it for 1 song at which point the neighbors complained but it was punching pretty hard! The rest of the night the cones were barely moving they are so efficient..
Top speakers were KV2 ESD12 and amps were Crown Itech 6000 for subs and Itech 4000 for tops - love this combo very smooth and punchy!
Top speakers were KV2 ESD12 and amps were Crown Itech 6000 for subs and Itech 4000 for tops - love this combo very smooth and punchy!
Fixed the IR windowing and added .9dB to compensate for 60Hz calibration with C weighted SPL meter.:
Yes, ground plane 10V 4Ω 5m IIRC. I'll check my notes tonight when I'm at home.
I have a TH18 loaded with B&C 18SW115 FOUR ohm drivers.
I am wondering if this amp would be OK for it
https://www.minidsp.com/products/plate-amplifiers/pwr-dsp1
Noted at 2400 watts into 4 ohsm. ( I think someone said the driver I has reaches xmax at 1100 average)
Plenty of headroom so I dont think it would run out of capacitence driving a sub.
The risk I think is that the tapped horn might shake the amp to death.
I am wondering if this amp would be OK for it
https://www.minidsp.com/products/plate-amplifiers/pwr-dsp1
Noted at 2400 watts into 4 ohsm. ( I think someone said the driver I has reaches xmax at 1100 average)
Plenty of headroom so I dont think it would run out of capacitence driving a sub.
The risk I think is that the tapped horn might shake the amp to death.