Something stirs in the Undergrowth

Dedicated to those large boxes at one end of the room
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izzy wizzy
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#2461 Re: Something stirs in the Undergrowth

Post by izzy wizzy »

IslandPink wrote: Fri Oct 25, 2019 7:23 pm
izzy wizzy wrote: Thu Oct 10, 2019 9:14 am Indeed. Early Xmas present so will have to wait to read it.
Ordered just now !
Me too :)
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izzy wizzy
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#2462 Re: Something stirs in the Undergrowth

Post by izzy wizzy »

Coz I had some issues with the website, spoke with Lean Audio today. He was a little unprepared for the demand. He's sold over 50 copies to date :)
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#2463 Re: Something stirs in the Undergrowth

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IslandPink wrote: Fri Oct 25, 2019 7:23 pm
izzy wizzy wrote: Thu Oct 10, 2019 9:14 am Indeed. Early Xmas present so will have to wait to read it.
Ordered just now !
Mine should be on its way too :) :) :)
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#2464 Re: Something stirs in the Undergrowth

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I'm looking at an annoying card from DPD, just working out how best to get my hands on it tomorrow.
"Once you find out ... the Circumstances ; then you can go out"
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#2465 Re: Something stirs in the Undergrowth

Post by pre65 »

IslandPink wrote: Wed Oct 30, 2019 6:13 pm I'm looking at an annoying card from DPD, just working out how best to get my hands on it tomorrow.
I have an old cold box on my front doorstep and give DPD authority to deposit my parcels in it.

But, I do live in a small rural village so, for me, it's a safe option.
The only thing necessary for the triumph of evil is for good men to do nothing.

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G-Popz THE easy listening connoisseur. (Philip)
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#2466 Re: Something stirs in the Undergrowth

Post by IslandPink »

Yes, I just asked them to leave it on the step .
Now I have it ...
Wow !
Wow ! :D
It's both enormous AND classy. A rare combination.
I shall start tomorrow reading the history section from beginning to end.
"Once you find out ... the Circumstances ; then you can go out"
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izzy wizzy
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#2467 Re: Something stirs in the Undergrowth

Post by izzy wizzy »

Wasn't prepared for how big and heavy it would be. It's definitely a sit it on the table read.

My neighbour bought it over as a "trick or treat" on Halloween with her kids all dressed up. What a treat!

But I have to wait until Christmas.
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#2468 Re: Something stirs in the Undergrowth

Post by SimonC »

IslandPink wrote: Thu Oct 31, 2019 8:39 pm Yes, I just asked them to leave it on the step .
Now I have it ...
Wow !
Wow ! :D
It's both enormous AND classy. A rare combination.
I shall start tomorrow reading the history section from beginning to end.
Mine arrives tomorrow :)
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#2469 Re: Something stirs in the Undergrowth

Post by IslandPink »

Well, embarrassing as it is, this is the first REW/UMC202 test of my right OB speaker unit, with both amps driving , and the volume controls set as they were when listening recently -
REW_first_1Nov19.png
I will now attempt some adjustments !
"Once you find out ... the Circumstances ; then you can go out"
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#2470 Re: Something stirs in the Undergrowth

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I'll try to capture the curves better next time.
Playing around a lot, learning some more tricks with the smoothing, and the 'All SPL's and 'average curves' options. Very useful.
Conclusion from the above test was that I don't have enough overlap between the HP and LP slopes ; the SPL was too low in the 2k-4k region - then I was compensating by raising the overall level of the tweeter too much . I'm on the case, have changed the caps in the tweeter HP to a bigger value, and will look again at the cap size on the zobel on the FX120 pair.
Looking better already though.
Thanks Chris !
"Once you find out ... the Circumstances ; then you can go out"
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#2471 Re: Something stirs in the Undergrowth

Post by chris661 »

No worries Mark.

FWIW, there's an icon just outside of the top left of the graph window where you can capture the graph and export as a JPEG, PNG or anything else you like. Quite handy, that.

IME, broad sweeps of frequency response can be fairly listenable once you've got used to them - it's narrow spikes that cause the problems.

Keep an eye on the distortion curve as you drive the tweeters lower.

Chris
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#2472 Re: Something stirs in the Undergrowth

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Did some work and got curves yesterday afternoon/evening.
Enlarged the cap on the tweeter HP (2nd-order) from 2.7 to 3.9uF
Reduced the cap on the zobel on the FX120 pair from 1.5uF to 0.47uF
( It remains to be seen how this sounds, as I had tuned that by ear trying to get rid of vocal harshness )
The I was able to reduce the tweeter amp level significantly to get these :
Here 5 captures with slightly different microphone position and angle. All around 1m from the OB
REW_5x_captures_Rev2.JPG
The angle of the mic is very critical in relation to the ribbon.
Here's an average of those -
REW_Avg_captures_Rev2.JPG
Bearing in mind the ribbon directionality I went back to 2.2m and added an additional curve -
REW_Avgplus2p2m_Rev2.JPG
Interesting to see the midrange change significantly due to room modes.
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#2473 Re: Something stirs in the Undergrowth

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Here's an average of everything -
REW_AvgAll_Rev2.JPG
One thing I noted is the fall-off over 13kHz. I saw this before with a 16-bit soundcard, and I can see 16bit on one of the set-up windows, don't think it was changeable, so I assume that's the soundcard limit. The ribbon shouldn't fall-off at that point.
I can't remember why 65536 ( 2^16 ) gives you 12 to 13kHz , can anyone remind me ?
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#2474 Re: Something stirs in the Undergrowth

Post by IslandPink »

chris661 wrote: Sat Nov 02, 2019 11:15 am 1. FWIW, there's an icon just outside of the top left of the graph window where you can capture the graph and export as a JPEG, PNG or anything else you like. Quite handy, that.

2. IME, broad sweeps of frequency response can be fairly listenable once you've got used to them - it's narrow spikes that cause the problems.

3. Keep an eye on the distortion curve as you drive the tweeters lower.
1. Thanks - I had resorted to the Snipping tool !
2. Yes, I've tried to avoid spikes by choice of drivers. There does seem to be a bit of a lump at 7kHz from the FX120's so it remains to be seen what the mods I've done will do to the sound.
3. Now this is something I was confused about. Presumably this info should come with the freq sweep ? I didn't seen any distortion data when I clicked the 'Distortion' tab - just a replica of the response curve. I will look & see - maybe I needed to tick boxes below to choose the harmonics. I was just focusing on the SPL at that point. I should do this at least on the ribbon before I mod the 2nd speaker and start listening.
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#2475 Re: Something stirs in the Undergrowth

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I can't remember why 65536 ( 2^16 ) gives you 12 to 13kHz , can anyone remind me ?
It won't, the sample rate will affect the HF cutoff, but in that case I would expect it to be a brickwall not a slow fall off. It could of course be your amplifier that’s driving the tweeter.
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