Something stirs in the Undergrowth

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IslandPink
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#2476 Re: Something stirs in the Undergrowth

Post by IslandPink »

Doubtful, given the concept of it and the parts choice. I should read-up on how to do that test though. Could it just be as simple as putting a resistor across the speaker plugs and clip-leading the ends to two of the pins on the XLR cable ? Obviously put the input level down a lot before firing it up.

One thing I should check is if both channels are the same in the HF. One tweeter was repaired - but from a bit of peering at them, I think it's the left channel that was repaired, I've been testing the right one.
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IslandPink
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#2477 Re: Something stirs in the Undergrowth

Post by IslandPink »

I tried to get some distortion data just now. Did full system first, then unplugged the bass/mid cables to look at the ribbon only.
I tried first and the noise floor was too high. Upped the drive level a few dB. Had a read of REW blurb and upped the data box from 256k to 1M for a longer sweep.
Still didn't solve the problem, what I see is this-
REW_Ribbon_Dist_2.jpg
This is with the tweeter output normalised - the flat line at the top.
Actual tweeter output is 15dB down at 2kHz and 30dB down at 1kHz.
But, as you can see, the noise floor is the top data curve, so all the harmonics are just following the noise floor.
Advice needed, I think.
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#2478 Re: Something stirs in the Undergrowth

Post by chris661 »

It's exactly what I'd expect for a relative curve of a band-limited device.
If something's putting very little out at 500Hz, then all of the measurement there will be noise.

Try having it not normalised and see what you get - it'll be the frequency response of the ribbon, plus actual distortion levels as measured.

Chris
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#2479 Re: Something stirs in the Undergrowth

Post by IslandPink »

I've got those curves as well, and the distortion products are all below the 'noise floor' curve. Given that the more or less follow the form of the noise floor , it doesn't look realistic - can't be useful data. If it was real data, I'd expect the 2nd/3rd/4th curves rising and swapping places to some degree as you head down from 2kHz to its cut-off.
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#2480 Re: Something stirs in the Undergrowth

Post by IslandPink »

Here's some interesting data. I've wondered for a while why it's harder to get Male vocals to sound right compared to Female.
https://erikbern.com/2017/02/01/language-pitch.html
The male vocal pattern for speech, at least , has more energy over a broader spectrum, than female speakers.
Maybe this means there's more potential for intermodulation distortion ?
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#2481 Re: Something stirs in the Undergrowth

Post by IslandPink »

First listening impressions of the revised crossover details & levels are not great, sort of 'ho hum' .
More tomorrow.
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#2482 Re: Something stirs in the Undergrowth

Post by chris661 »

I can imagine that, if you're used to it, losing that much treble energy would be problematic. Give your ears a little while to adjust and hopefully you'll be more pleased with the performance.

With regards to the distortion, it might be worth raising the sweep level a little to get the signal above the noise. IIRC the ECM8000 has a relatively high noise floor - it's a fairly cheap mic, after all.

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#2483 Re: Something stirs in the Undergrowth

Post by IslandPink »

OK yes. I was definitely adapting to less treble. However there is a return of the 'crud' I could hear on vocals, as if there is dirt on the stylus ( which there wasn't ). I fear the reduction of the zobel correction of the FX120 pair is just giving me the problem I had a while back, due to the twin drivers.
On the basis that I can't see any distortion from the tweeter yet, I am going to get parts to bring the crossover down a little to 3kHz 2nd-order.
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#2484 Re: Something stirs in the Undergrowth

Post by IslandPink »

Ps. the obvious but unpalatable way out of this ( for Colin's benefit , for instance ) is to buy one of the best 8" FR drivers with the right properties ( Q approx. 0.35 to 0.4 , 95dB/w ) . This would solve the bass padding-down problem , and hopefully would run to 2-3kHz with less trouble than a pair of mid drivers, to hand over to the ribbon at 4kHz as before.
This would require the AER's if there were one made now that is the same as James's ( which there appears not to be ) at about E3000 each or upwards.
Or the Enviee 8" FR by Joachim Gerhardt , which seems to be very hard to find a price on now, or anyone selling , so may be defunct ...
or the Cube Audio Magus 8" , about E2500/pr ...
So this is why I persevere.
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#2485 Re: Something stirs in the Undergrowth

Post by Nick »

This would require the AER's if there were one made now that is the same as James's ( which there appears not to be ) at about E3000 each or upwards.
Or the Enviee 8" FR by Joachim Gerhardt , which seems to be very hard to find a price on now, or anyone selling , so may be defunct ...
or the Cube Audio Magus 8" , about E2500/pr ...
So this is why I persevere.
Which (at least in the case of two of them from Munich) are not without their own issues. The AER's were the best, but only in one of their own speakers, the other use they made of them were also questionable to my ears.
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#2486 Re: Something stirs in the Undergrowth

Post by ed »

IslandPink wrote: Sun Nov 03, 2019 10:21 pm
Or the Enviee 8" FR by Joachim Gerhardt , which seems to be very hard to find a price on now, or anyone selling , so may be defunct ...
So this is why I persevere.
is the price shown on the website not valid? It says 680 euros each.
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#2487 Re: Something stirs in the Undergrowth

Post by steve s »

IslandPink wrote: Sat Nov 02, 2019 10:56 pm Here's some interesting data. I've wondered for a while why it's harder to get Male vocals to sound right compared to Female.
https://erikbern.com/2017/02/01/language-pitch.html
The male vocal pattern for speech, at least , has more energy over a broader spectrum, than female speakers.
Maybe this means there's more potential for intermodulation distortion ?
Goes to show how important your bass drivers are for good reproduction of male and female voices Mark.
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
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#2488 Re: Something stirs in the Undergrowth

Post by steve s »

IslandPink wrote: Sun Nov 03, 2019 1:41 pm OK yes. I was definitely adapting to less treble. However there is a return of the 'crud' I could hear on vocals, as if there is dirt on the stylus
I may be off track here Mark but the fx120 are likely to struggle to reproduce the vocal fundamental?

My lowthers only came into their own with some female vocals.. some where too low, it wasn't until I combined them with the big goodmans, then all was exposed ?
My musical tastes then broadened

It's likely the Enviee may well struggle looking at the measurements?

It's how all the drivers play together that counts...

Edit.. I'm not sure how you are evaluating the drivers Mark ( open baffle or back horn?) But if its in open baffle are you cutting the bottom end?

I could not run my Lowthers wide open in baffles, they needed a cap cutting the sub 100hz or they too could sound fuzzy... just a thought ?
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
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#2489 Re: Something stirs in the Undergrowth

Post by Toppsy »

Mark,
Have you checked out any the SB Acoustics PA drivers? They trade under the SB Audience name: http://www.sbaudience.com/

I understand they are developing a Satori range of woofers with their new Textrene CF cones. They certainly look very interesting being a woven carbon fibre material. Check out SB Acoustics web site in their 'coming' and 'news' pull down menus : https://www.sbacoustics.com/
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#2490 Re: Something stirs in the Undergrowth

Post by vinylnvalves »

There seems to some discussion about this 10” FR driver which should be good under a ribbon. It’s a copy of the coral drivers of old. https://www.diyaudio.com/forums/full-ra ... und-3.html
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