Something stirs in the Undergrowth

[IslandPink]

I have been mulling over the problem here and remembered back to Lynn Olson's explanation of how the 'Ariel' crossover was designed.
In his case there were parallel Vifa 130mm drivers.
http://www.nutshellhifi.com/Arieltxt2.html#top
(See second circuit and discussion )
So it's basically a zobel for the pair.
I could do the same for the FX120's & hope it works in conjunction with the series crossover - I think it would.
FX120 'Le' is awol on datasheets and forums but an estimate from other drivers in their range is 0.05mH.
I get the following first estimate from MH Audio -

I could quite easily find the parts, so I might try & lash this up at the end of the week before I go away on hol.

[IslandPink]

Ps. I understand now why the Ariel sounds a bit dead & lifeless. The Vifa drivers (P13WH-00-08) are very mechanically damped - Qms = 1.38 and Rms approx. 2.0.

[IslandPink]

More stuff here.
I do think at the moment that my progress is 'compound in its directness', like The Fall.
A pair of tweeter blending pieces, designed by a good fella at work and hot off the machine, nuff said, you ain't seen me, etc :

I may or may not decide whether to have M4 helicoils installed for the mounting screws - needs a bit of checking of the density of the material.

[ed]

Ps. I understand now why the Ariel sounds a bit dead & lifeless. The Vifa drivers (P13WH-00-08) are very mechanically damped - Qms = 1.38 and Rms approx. 2.0.

I've seen this 'black and white' statement before, and as before I have to defend the ariels.....
A different partner may give a completely different appraisal....
yes, I've heard them dead and lifeless, but I've also heard the complete opposite from them.

[chris661]

Thinking back to the meet we had at Steve's a while back, the "dead and lifeless" could simply have been a lack of grunt from the amplifier.
The Fanes came to life more, particularly in the bass and with big dynamic swings, when a large amplifier was connected.

A complex multi-way driven by a single-digit-wattage SET might not have been doing either side justice.

Chris

[IslandPink]

Yes, fair point Ed, my language was a bit loose, I did enjoy them quite a lot at times myself. I wouldn't go for drivers like that these days though. Did you find higher-power SET amps were enough, or solid state ? I think the Aurora PP 300B was the best of my amps for driving them. It's an interesting point to speculate how a beefier amp would overcome the mechanical damping at low excursion levels, though. Is it purely about low Zout ?

[chris661]

I think we concluded that it was "current reserve". Low Zout, and a power supply you can weld with - there are 2x 15,000uF, 110V caps per channel on the Crown amp we liked (MA5002VZ). The newer one (MA12000i) wasn't as good, although that could be down to running right down in the noise of such a powerful amp.

My suspicion regarding the Ariels was that a low-powered amp combined with lossy drivers (and probably a lossy crossover, too) would mean it'd be pretty easy to clip the amplifiers on transient peaks, while a bigger amplifier would be happy to put out the larger voltage swings.
At lower levels, it's difficult to say.

We did note that the Crown amps were happy to go along with big dynamic changes compared to the low-power valve amps on the day. Away from clipping, there were still some differences that could be down to the usual suspects - distortion profile, Zout, etc.
I quite liked the analytical presentation given by the solid-state amps, but I'm a sound engineer and I want things to sound right. The valve amps sounded nice, but the fact that they were imparting a little of their own tone meant they're not really for me.
I think the OTL sounded nicest on the day - a good compromise between very neutral and imparting a little character. A high-power version would be a lot of fun.

Chris

[Nick]

"current reserve". Low Zout, and a power supply you can weld with

Are they basically not the same thing, the ability to deliver current into the load?

[ed]

Yes, fair point Ed, my language was a bit loose, I did enjoy them quite a lot at times myself. I wouldn't go for drivers like that these days though. Did you find higher-power SET amps were enough, or solid state ? I think the Aurora PP 300B was the best of my amps for driving them. It's an interesting point to speculate how a beefier amp would overcome the mechanical damping at low excursion levels, though. Is it purely about low Zout ?

After all this time I still wouldn't like to speculate about what makes single items sound so different with differing partners. In truth I don't think I've ever had a single ended amp that rose above 5 watts so my experience rules out the power argument...
Ariels with WAD 6550 were pants, but then again quite a lot of my speakers didn't like that amp, but it had measurable power(40w).

More realistic comparisons:

EL34 SE with Hammond outputs was ok ish (5w) out z 3R ish
F2 was better(5w) out z 15R
F4 better still(5w) out z 0R2
Aura 40 SS pp(40w) nice out z 0 ish
2A3 SE with James outputs was nice(5w?) out z 3R ish still use it for far field balancing.
F6 the best I've got(25w) out z 0R5

All the F amps have 120000uf in the power supply, I'm sure it's a factor but how much I wouldn't like to guess. For me, at the end of the day you can predict the synergy looking at the theory but the real thing still provides surprises.

I still like the ariels in the studio...when miking instruments they still duplicate the sound of the real thing for me. Others I have experience of, Mackies, Tannoys, diy MAs, have all fallen down in some areas, but then I've always used these near field.

[chris661]

"current reserve". Low Zout, and a power supply you can weld with

Are they basically not the same thing, the ability to deliver current into the load?

I was wondering that myself.
Can Zout change under heavy loading?

Chris

[Nick]

Output impedance is a misleading thing. It means nothing unless its considered in conjunction with available current. You can make a white cathode follower using a ecc83 that has a low output impedance, but can't deliver more than a few tenths of a milliamp of current. Also in the real world output impedance is complex and so frequency dependent. And finally its unlikely to be linear, so may itself be a source of distortion.

[Scottmoose]

Not had a whole lot of sleep lately & taking some time out of work for a few minutes.

I like the Ariels within the context of what they are; they're capable of extremely good (exceptional) results, but they're not a jack-of-all-trades design; they're tightly optimised into a particular set of goals. There's two major pieces of EQ in them for a start; a fairly broad Gundry style depression through the midband, following the alignment Lynn was targeting, and they also have a gently declining response as frequency increases. So they aren't likely to ever project like some speakers voiced to be flat or even slightly elevated through this range.

On a related level, in large[r] spaces I wouldn't be surprised if the Ariels sounded a bit polite in the upper midband, especially off-axis due to the high 3.8KHz crossover frequency. The Scan tweeter is radiating over a wide angle at and around that region, while the P13s are becoming increasingly directional. MTMs tend to be rather directional on the vertical axis by nature and a higher XO frequency increases the likelihood of that on the horizontal also. In smaller spaces / closer in, this becomes less of an issue on the horizontal plane. Design choices -the high XO in the Ariels means more radiating area in the telephone band -the above is the price for it. Name your poison.

[IslandPink]

1. In truth I don't think I've ever had a single ended amp that rose above 5 watts so my experience rules out the power argument...
2. Ariels with WAD 6550 were pants, but then again quite a lot of my speakers didn't like that amp, but it had measurable power(40w).

3. I still like the ariels in the studio...when miking instruments they still duplicate the sound of the real thing for me.

Thanks for the amp info & comparisons.
1. You did have that 572 amp, and having heard bigger plates and/or thoriated filaments in my system, I do have a suspicion one of those things can give more low-level info on a given set of speakers.
2. I borrowed that amp years ago and only played it for a day till I lost interest. I don't think it was doing things right at low levels and the tone was dominated by 3rd & 5th harmonic - horrible.
3. I won't fault the Ariels on tonal balance and natural tone. Vocals and instruments were very believable. Polite perhaps in the low treble, but very listenable long-term, no shrillness. The problem, which I still maintain is due to the woofer's Qms/Rms, is that below a certain signal level the tone and details sort of disappear. There isn't the same level of 'stuff between the notes' that happens with something like an FX120 or a FE208Ez, or a compression driver. I think it helps to play the Ariels louder than I would typically want to do - for instance in something bigger than a normal living room. The top-end roll off was a bit too much for some tastes, but that was fixable as he suggests in the articles.
The worst speakers I've heard like this was a pair of Kef ones my mate Lenny had about 15 years ago - you had to get them to where they were uncomfortably loud in a normal living room, before they started to produce any meaningful tone.

[IslandPink]

Not had a whole lot of sleep lately ..

Ping me a PM if this is something having trouble with.

[ed]

all good by me....
except:
1. the sv572 is about 3.5 watts with a following wind and I've never tried it with the ariels...it's a true unknown.
2. the ariels have never left the studio since I built them....they've led a very sheltered existence...sadly.

I guess I'm only really responding to the 'dead and lifeless' charge.