Best new midwoofer?

[ErinH]

Re: Best new midwoofer?

I wouldn't compare the rev to this; it looks more like the illuminator. Which, BTW, bested te SB in the Nivember issue of Voice Coil magazine on the klippel. IIRC, the scan 18wu has about 5mm more linear Xmax one-way as shown via klippel testing.

If someone wants to send me a satori id be happy to provide some data via my klippel and you can compare it to my scan results.


IMO, the scan illuminator beats this driver for best mid woofer.

[Jeff B.]

Re: Response and Distortion plots.

As promised here are some response and distortion plots of the Satori woofer:

Here is the frequency response on a 16" x 9" baffle:


You can easly see the baffle step and then the baffle "bump" at 1khz, however, most of the higher frequency peaks and dips are diffraction effects as well. If these were all removed then the response would be remarkably flat to 15kHz. A perfect woofer for a transient perfect application

The dip at 1.2kHz does appear to be real though, and based on the distortion plot below (even order peak at this frequency), I believe it is caused by the cancellation from the soft surround. I still don't think it matters much at all though - narrow, higher Q dips like this are very difficult to discern audibly and should be completely unobjectionable.

Here's the distortion:


With a 100dB reference level, 3rd order harmonics run -55 to -60 dB all the way up. That is a incredible performance.

Jeff

[internova]

Re: Response and Distortion plots.

Jeff,

What setting did you use for OmniMic? I can never get something that clean from my measurement. I must do something wrong. The distortion looks very good!

As promised here are some response and distortion plots of the Satori woofer:

Here is the frequency response on a 16" x 9" baffle:


You can easly see the baffle step and then the baffle "bump" at 1khz, however, most of the higher frequency peaks and dips are diffraction effects as well. If these were all removed then the response would be remarkably flat to 15kHz. A perfect woofer for a transient perfect application

The dip at 1.2kHz does appear to be real though, and based on the distortion plot below (even order peak at this frequency), I believe it is caused by the cancellation from the soft surround. I still don't think it matters much at all though - narrow, higher Q dips like this are very difficult to discern audibly and should be completely unobjectionable.

Here's the distortion:


With a 100dB reference level, 3rd order harmonics run -55 to -60 dB all the way up. That is a incredible performance.

Jeff

[mzisserson]

Re: Best new midwoofer?

That stuff at 1.2K is just annoying for the price that driver carries. I measured a similar speaker using a proprietary cone That had a similar blip. Turned out to be energy storage right where the VC meets the cone and was highly audible and annoying.

Look around 1.6K attached. This speaker measures great but was unlistenable for long periods of time. Showed up as a phase and impedance blip too. Ironically it was the audible nature of what this was doing to the sound that made me whip out the measuring equipment.

[ErinH]

Re: Response and Distortion plots.

Jeff,

What setting did you use for OmniMic? I can never get something that clean from my measurement. I must do something wrong. The distortion looks very good!

X2

What kind of windowing do you use, what stimulus, and what is your room like? It looks as though you have an anechoic chamber or are nearfield. I've not been able to get that smooth of a response in the farfield ever. I'm jealous!

[dthomas]

Re: Best new midwoofer?

That stuff at 1.2K is just annoying for the price that driver carries. I measured a similar speaker using a proprietary cone That had a similar blip. Turned out to be energy storage right where the VC meets the cone and was highly audible and annoying.

Look around 1.6K attached. This speaker measures great but was unlistenable for long periods of time. Showed up as a phase and impedance blip too. Ironically it was the audible nature of what this was doing to the sound that made me whip out the measuring equipment.

Look at the Usher 8945P it has a similar issue but far from annoying. Not sure you can ascertain that the blip is anything to even concern yourself with. I did several iterations of crossover on the Usher trying to tame it's blip only to end up deciding that it sounded no better just ignoring it.

As far as why the measured driver was unlistenable I think you need to look at more than just the FR response, got any distortion plots on that driver. To me high order distortion can be very discernable regardless of how the driver measures.

[Pete Schumacher]

Re: Best new midwoofer?

Look at the Usher 8945P it has a similar issue but far from annoying. Not sure you can ascertain that the blip is anything to even concern yourself with. I did several iterations of crossover on the Usher trying to tame it's blip only to end up deciding that it sounded no better just ignoring it.

As far as why the measured driver was unlistenable I think you need to look at more than just the FR response, got any distortion plots on that driver. To me high order distortion can be very discernable regardless of how the driver measures.

The distortion is shown, and if you look closely, there are two harmonics converging at 1.6KHz, but which two is tough to tell (2nd and 4th?). It's not surprising that was audible.

[Jeff B.]

Re: Best new midwoofer?

That stuff at 1.2K is just annoying for the price that driver carries. I measured a similar speaker using a proprietary cone That had a similar blip. Turned out to be energy storage right where the VC meets the cone and was highly audible and annoying.

Look around 1.6K attached. This speaker measures great but was unlistenable for long periods of time. Showed up as a phase and impedance blip too. Ironically it was the audible nature of what this was doing to the sound that made me whip out the measuring equipment.

Well, in this case, I really believe it is from the surround. It does not show up in the odd order distortion, and I still really do not think it is an issue at all.

By the way, a driver can't measure with flat frequency response and have a phase issue at that frequency at the same time, unless it has somehow become non-minimum phase. I guess a detached voice coil might behave that way, or a tear in cone.

[Jeff B.]

Re: Best new midwoofer?

The distortion is shown, and if you look closely, there are two harmonics converging at 1.6KHz, but which two is tough to tell (2nd and 4th?). It's not surprising that was audible.

I only know this because I have the OmniMic too, but the blue line is Total Harmonic distortion. The pink line that is running with it is 3rd order distortion. At that frequency nearly all of the THD is a peak in 3rd order. There is very high non-linear distortion at that point which probably does make it scream in this frequency range. It would imply something is wrong with the speaker though.

[dlr]

Re: Best new midwoofer?

The dip in response won't be the same when placed on a baffle, and likely would be hard to hear anyway.

Why would you think that? Most often when a dip like this "disappears" or is diminished it's because of measurement conditions, smoothing due to windowing an impulse, not from a change in driver response. Unless, of course, diffraction enters into it, but that is dependent on the axis, so whatever change occurs is not constant in the polar response.

dlr

[Pete Schumacher]

Re: Best new midwoofer?

Why would you think that? Most often when a dip like this "disappears" or is diminished it's because of measurement conditions, smoothing due to windowing an impulse, not from a change in driver response. Unless, of course, diffraction enters into it, but that is dependent on the axis, so whatever change occurs is not constant in the polar response.

dlr

Diffraction.

And with a narrow baffle like most use, that bump at the transition will show up over a fairly wide listening angle.

[dlr]

Re: Response and Distortion plots.

The dip at 1.2kHz does appear to be real though, and based on the distortion plot below (even order peak at this frequency), I believe it is caused by the cancellation from the soft surround. I still don't think it matters much at all though - narrow, higher Q dips like this are very difficult to discern audibly and should be completely unobjectionable.

Measure off-axis. If it's the surround, it should change quite a bit with axis, more with increasing angle. If it's a spider resonance, it won't change much.

dlr

[Whitneyville1]

Re: Best new midwoofer?

I'll ask the foolish questions. Why would I buy this mid-woofer over the Peerless 830875 or Tang Band W6-789E? (These are examples that give you the idea.) I want to learn, really. This is a "price point" I don't look at normally. I understand the principals of low distortion and excellent low Fs, but otherwise, most of this is over my head. Jeff B. ,I know you are a reliable source and can help an idiot like me.

[Jeff B.]

Re: Response and Distortion plots.

Measure off-axis. If it's the surround, it should change quite a bit with axis, more with increasing angle. If it's a spider resonance, it won't change much.

dlr

With the holiday approaching I'm not sure when I will get a chance to do that, but I might give shot sometime and see.

[dthomas]

Re: Best new midwoofer?

The distortion is shown, and if you look closely, there are two harmonics converging at 1.6KHz, but which two is tough to tell (2nd and 4th?). It's not surprising that was audible.

Yeah I looked fast and didn't notice the bottom of the graph. But definitely a peak in distortion in that area. There are a lot of drivers that peak in that region and the results can be very audible.