I'm not following--the peaking looks more like 4-5 dB. and above the upper treble deviations using the listening window plot as a reference.The impact of the 1 kHz is small relative to overall boost in that region. You can see it in my measurents:
You can see just a 1 dB or so peaking which is not going to very audible. Erin's measurements of the same are too smoothed to show it.
EQ I developed fixes the broader deviation:
There is a broad boost which could be what you are talking about as far as baffle step. But there is a tiny narrow peak which is the cabinet resonance:
Couldn't that boost be caused by a louder mid-range? By simply looking at the mid drive unit, I wouldn't expect it to go much lower than 1kHz. We can see from the spinorama that the cut off to the tweeter is around 2kHz. A sensitivity miss-match on the mid driver plus the resonance peak and an imperfect twitter crossover may well get that broad boost at 1-2kHz -- me thinks.
I've been working a little on a similar issue, as I am wrapping up the design for a relatively shallow speaker intended to be placed on a ledge near a back wall. It has a front port with some resonance issues, so I have been working on a relatively DIY-friendly solution using hand-drilled perforations. Rather than repost here, I'll link to my thread on the Midwest Audio Club forum. I'm not sure what might be accessible to modify with respect to the Neumi port, but this thread at least walks through a process and has seemed to have tangible results.
Sure. I did not try to diagnose the causes when I was measuring this speaker compared to what I do now.
I was just going to suggest inserting a bunch of soda straws into the port. That's worked for me in the past, although it does reduce the output a bit. But there's not a lot of bass to lose, and it would be better than stuffing it completely.
It's the woofer response. Here's the filtered response for the main tweeter. There's nothing going on at 1 kHz
I'm no expert on port dynamics, but I guess the theory rests on the proposition that a bajillion little ports each with a very high ratio of length to diameter will be less prone to a pronounced resonance than a single port with a lower ratio of length to diameter. There's probably more to it. I first encountered this approach on my 1980's Proac Tablettes, which for whatever reason did have an extremely smooth midbass response.
I was commenting on the broad lift in the 1-2kHz range, which is where the mid driver operates. If you have individual plots of all driver may I ask you post all three (or four including the port) FR on the same chart?
That's the other element I was trying to remember--more resistance. But I don't really understand the details on exactly how that works to reduce resonance. Looks like I'll actually have to try sticking some straws up the Neumi.
I would be happy to post the individual driver measurements, but first I have to understand your terminology. There is no midrange on the Sony. There's a mid-woofer, a main tweeter, and a super tweeter. What I posted was the response of the main tweeter with the stock filter in place. The woofer response will show all of the peaking in the 1-2 kHz region.
I use the terms tweeter, mid range and woofer for the drivers that emit audio in the top, mid and low range of the the spectrum, whatever their crossover frequencies are.
As I said, there is no midrange on the Sony. What I posted was what you are referring to as the midrange. It's actually just your standard 1" dome that operates from about 3 kHz on up to above 10 kHz, where the super tweeter takes over. I'll post all of the curves after I mail some Xmas presents.
We are miscommunicating. I am using the word mid as the middle of the high and low ranges. I am not defining where that range start and end.
Just to confirm it's a 2-way with a little "super" tweeter stuck on top. There is no low pass filter on the main tweeter--it just rolls off on its own. I'm still not exactly sure what you're looking for--it's obvious the response deviations in the 800 - 1500 Hz area are embodied in the woofer measurement, but here's a plot that shows the overall frequency response and the filtered response of each driver. The cabinet resonance may be contributing a little to the bump, along with inadequate baffle step compensation and probably also a resonance from the junction of the woofer cone and surround.
First of all thank you. I think I understood the topology.
And just to close the circle on this, here's a plot of the raw woofer response (no filter) in the stock cabinet, and then with 3" wings added to each side.
