Something stirs in the Undergrowth

[IslandPink]

No I think you're keeping up better than most.
Yes, Supravox.. I don't think the 285 is quite articulate enough in the midrange compared to a smaller driver.. but I may be wrong. there was a test I did - but I'd need to go back and see what i was trying to blend it with. It's a good point to revisit.
I do rather like the idea of alnico for a mid-driver though - Nick has sent me comments on email that confirm my interest in this. However the PITA of the Lowther is the ±1mm Xmax ( at least the linear Xmax ) which could cause problems much below 100Hz.

[simon]

No I think you're keeping up better than most.
Yes, Supravox.. I don't think the 285 is quite articulate enough in the midrange compared to a smaller driver.. but I may be wrong. there was a test I did - but I'd need to go back and see what i was trying to blend it with. It's a good point to revisit.

That's interesting Mark. I've been weighing up something which is seems to be similarish to you and was intending to use the 285s in OB between 100Hz and 600Hz so I'd be interested in your thoughts if and when you find them.

[IslandPink]

Noted
'Course I can see one option to address the excursion issue is 2x Lowther PM6A 16-ohm, in parallel - to match the Bud GM70 outputs which I foolishly specified as 4 / 8 ohm !

[vinylnvalves]

Mark, you were going down the route of a midrange horn, a smaller direct driver isn’t going to move enough air to replicate the effect your after in my opinion. Look at the JBL Studio Speaker big midrange drivers. Have a look at what Troels does with this http://www.troelsgravesen.dk/The-Loudspeaker. There are some interesting 10” midrange drivers he played with.

I tried a pair of BG NEO 10 drivers they didn’t have the surface area to work well with the TPL’s. 3 per side is what the guys in the USA were using with TPL’s. They are working very well in the modified LX521’s of Daves being cut in an octave higher.

Not sure what the other Steve uses in his system think it’s a 12” midbass driver.

My current midrange AMT’s have the surface area of a 9” driver which upto 5k gives me a similar effect as I get with the 2” compression drivers.

[IslandPink]

Link doesn't work.
it's not about moving air, it's about tone, low Rms etc etc
Sorry for curt reply, Not the best day I've ever had, more soon, over & out.

[vinylnvalves]

http://www.troelsgravesen.dk/The-Loudspeaker.htm Missed the ending of it.
If you want low mechanical compliance (RMS) foam surrounds or the animal skin of some boutique drivers generally the way to go, or go electrostatics. A pair of Quads would make nice midbass drivers

[steve s]

Not sure what the other Steve uses in his system think it’s a 12” midbass driver.

My current midrange AMT’s have the surface area of a 9” driver which upto 5k gives me a similar effect as I get with the 2” compression drivers.

Thats correct steve, I use a high efficiency 12" driver, with a whizzer.. although I cut it off well before the whizzer comes in.
To me the area it covers is easy to mess up.
The ability to convey both dynamics and the finer nuances that make the reproduction believable (read realistic tone !), for me only come with surface area... and only a handful of quality drivers tick my boxes... and those need careful implementation to ensure the rougher parts of their response is not relied upon.

[IslandPink]

Well said, absolutely agree with you on those points. Your speakers can play vocals really loud without them sounding harsh - a very hard thing to achieve, almost all speakers fail this test.

[steve s]

Well said, absolutely agree with you on those points. Your speakers can play vocals really loud without them sounding harsh - a very hard thing to achieve, almost all speakers fail this test.

Well I have had plenty of practice building speakers over the last 25 years mark.. and many disappointments
For me its always been about the drivers and implementation .. and slowly recognising, with the help of you lot of course, what speakers should achieve.
I remember when I bought my first lowther drivers in the mid 90s I could pick out what they did best, and many aspects of thier performance was much better than other drivers I'd used. But it took 10 years with them before I managed to get a sound that was something like though.
. It's difficult on your own to judge loudspeakers, i reject aspects that are not right, but accept other aspects... until some one else points them out for being wrong.. dohhh !!!

[chris661]

Well said, absolutely agree with you on those points. Your speakers can play vocals really loud without them sounding harsh - a very hard thing to achieve, almost all speakers fail this test.

In terms of requirements, this is pretty straightforward: whichever driver(s) are covering the vocal range need to be capable of plenty of clean output. Drivers sound bad when pushed towards their limits, which is why systems tend to struggle at Owston.

IIRC, Steve uses high-efficiency drivers and not-much power. The drivers, then, will be operating well within their comfort zone.

I think we've discussed Rms before, but needless to say I'm not convinced low Rms = high quality reproduction.

Chris

[steve s]

In terms of requirements, this is pretty straightforward: whichever driver(s) are covering the vocal range need to be capable of plenty of clean output. Drivers sound bad when pushed towards their limits, which is why systems tend to struggle at Owston.

IIRC, Steve uses high-efficiency drivers and not-much power. The drivers, then, will be operating well within their comfort zone..

Chris

Yes but no but...
You are correct that many 'hi fi' drivers are soon out of their comfort range when used in a larger room.
But most pa type speakers will do reasonable volume without to much compression/ distortion, but that does not mean that they are all high resultion drivers..
in most cases you get what you pay for and drivers usually work best where they are spec'd to work

As you well know chris..

I do not think any one spec is a measure of a drivers quality
My judge of a good driver is its transient response, its ability to reproduce.
But that is easily spoiled by lots of other externals, namely the implementation and the quality of signal it fed,
I know how my speakers react to different amplifiers and sources, and it more often negatively.

[steve s]

Adding to my last post, it appears to me to be quite a difficult thing to build really good hi fi, much more difficult than one thinks starting out, when you've just built your 1st amp or speaker

I think is more about understanding the simple aspects of speaker and amplifier design, treating every component in the signal path as the enemy. And choosing everything in the signal path (drivers included) for their ability to be amongst the best at what they do.
Then the bit that trips every one up.. what's the 'best' and what do you base your judgement of the best on.

My speakers sound like they do because of my driver selection and my views on ways of getting the best from them. Im sure theres still have room for improvement, but I'm happy that my logic has got me to where I am.
Could I build my speakers with different drivers and cab design.. maybe, but I doubt it.
I use the same logic on the amps I build and use

My logic is routed back to my lowther days, recognising the quality aspects of the driver and not confusing that with poor implementation, which in my view is the most common lowther criticism, and what they get knocked for, along with a peakyness..
That peakyness to me is a positive to be utilised.. not to be flattened, now that may take some thinking about, but its they way I look at things, and the basis of the logic that's got me to where I am..

[Nick]

I would agree with that Steve, I think the first part of the problem of

it appears to me to be quite a difficult thing to build really good hi fi

Is that it can take some time to find just what "really good hi fi" sounds like, or rather the number of things it can sound like. I am of the view that like convergent evolution, its possible to start in different places, with different plane, and by applying the picking the best and throwing the rest strategy you suggest, its possible to arrive and several entirety different solutions that in their own way produce a equally valid version of "really good hi fi"

I would also say that to do that you really have to apply the "throwing the rest" even though that can be inconvenient and expensive. Clinging to a solution for reasons of simplicity or as I often suggest dogma, can prevent the "really good" from ever being reached.

I would consider this thread as a shining example of that process in action and a striking example of the difficulty it can involve.

[IslandPink]

Wise words.

... a striking example of the difficulty it can involve.

Glad to be of service

VnV-Steve, you say foam surrounds for low-Rms, but this is an incorrect generalisation - many new or vintage drivers with concertina surround are low-Rms , often it's the spider rather than the cone surround that is driving the Rms value. Of course, old-school compression drivers with aluminium diaphragms and flexure surrounds are a very good way to get low Rms ..... ( as are Quads, fair point ! )

There are a couple of ways I think the next experiment will be different.
In the past, when I tried to combine a cone and the horn, I had two problems getting in the way -
1. Trying to run a 2-way bass and mid OB , with crossover at ~200Hz, then applying a 600Hz LP to the whole affair , to cross to the horn.
I realised in the end that the 200Hz cross was still affecting the phase at 600Hz, and messing up my calcs about driver placement
2. Driver placement - of the cone relative to the compression driver. I was trying to get physical alignment, but not realising that a cone in its mass-loaded region is moving with 90° phase lag relative to the signal. This means the midrange cone should have been at least 6" further forward than I was trying.

[vinylnvalves]

Mark, you are right about my overgeneralisation of foam surrounds. Lowthers and the like which I had in my mind don’t have spiders totally relying on the surround for the damping. I did a decade or so back replace the surrounds on some generic 15” PA drivers with some foam surrounds. Dropped the FS by around 10Hz.. They didn’t measure as well as a pair of Beyma 15BR100’s I borrowed for testing, so got consigned as failed. I never however messed with the spider, a missed opportunity maybe.
Here’s a link to a spiderless midrange drivers concept which use electromagnetic suspension, the inventor finally made it to market when it was patented.https://www.diyaudio.com/forums/multi-w ... river.html