Field Coils for Audio Systems

[jeff1225]

Do you or Ralph (@Atmasphere) know the Web address for Classic Audio Loudspeakers?

It does not appear to be:
http://classicaudioloudspeakers.com which redirects to

Classic Audio Loudspeakers

There's a page there but tjat shows only a box with a blue border and no content.

The website is correct and I can see it fine on my iPhone. It’s an old school and somewhat primitive website.

 

[tima]

The website is correct and I can see it fine on my iPhone. It’s an old school and somewhat primitive website.

Thank you. I use Firefox; not sure what its' problem is. The site rendered fine in the Brave browser.

 

[morricab]

My position is similar.

I have heard and enjoyed Lowthers on many occasions, but did not feel that I could live with them. I have been curious about the Voxativ and AER, and also the Feastrex.

I chose to go with Supravox widebander because there is no wizzer and therefore I felt that I could integrate a tweeter and have a smooth
response.

Will be watching with anticipation on how Bill's experiment goes.

I also have a Supravox (215-2000) but it is not extended enough for full range IMO. I couple it with a horn for a two-way system.

 

[Atmasphere]

Thank you. I use Firefox; not sure what its' problem is. The site rendered fine in the Brave browser.

I'm experiencing the same thing- its something to do with Firefox.

 

[Audiophile Bill]

I simply avoided Lowthers as i found them too shouty and when you see their breakup in the highs it is easy to know why. The only way i heard them work was with the whizzet removed as in Horning speakers, which I like. I am not sure how AER managed to avoid this without resorting to multiple whizzers like Cube Audio but their measurements suggest they figured it out. Voxativ seems to have at least partially overcome this as well. That said, i haven't heard a single driver whose treble i could live with. I hear some breakup on all of them (even the AERs I have heard at shows). Based on comments about your system, perhaps you have done something that could convince otherwise...

Lowthers in front loaded horns are very different beasts to back loaded horns where the rising frequency response gives the infamous shout. I am certainly no proponent of Lowther back loaded systems although I can appreciate what they can do on some genres.

With a suitable front loaded horn, one can apply the acoustic loading to the lower range of the driver which effectively leads to much flatter response.

I am also a big fan of Horning speakers and TTs since I own the latter. There is something so alive about Lowthers. In terms of using it as say an extended mid range - yes that is a good plan but you will pay a price adding a tweeter no matter what people say imho ymmv.

AER drivers just sound much more linear altogether than Lowthers. They also extend right the way to 20k with no problem. In fact the treble is the region which is so sweet and resolving on the AERs - I would say it is their absolute forte. I don’t think I heard a violin ever as good as through an AER.

I am not here to try to convince anyone of anything though - just reporting my preferences and experience.

cheers

 

[shakti]

So my question - what did you mean specifically when you say “field power?”

Line Magnetic is offering different Power Supply units for their field Coils chassis

??????????-??????????

some of them are high voltage, low current, some are low voltage and high current.

I using 1x LM PR-12 PSU (low voltage high current) to drive both of the LM-755 speakers. On PR12 it is possible to adjust the output, which will effect the magnetic field power (Tesla), which is easily audible. I shared mails with Line Magnetic Foshan to get their recommendation about the "best" voltage/current feed of the field coils system for my LM-755.

“Weight of the magnet is much higher than a 2nd coil which has huge effect on resonances…”

> I am not sure what you mean? You mean that a field coil motor tends to be lighter than an associated magnet? Are you saying lighter or heavier is better?

If the field coil motor is lighter, what is true for many of them, the resonance frequency of the chassis body is higher.

there is no better for higher or heavier, but there is a "best" area of resonance for a chassis body and it is in theory more easy to add weight than to reduce weight.

On the whole, the field coil motors I have seen in production are very big and heavy devices. Mine are 15kg each.

“Inproved airflow”

> I am not following how airflow is improved? Please could you explain a little more?

I have never seen a 15kg field coil motor, from there, I suspect no improved airflow due to a smaller back of the chassis with your field coil motor.

 

[shakti]

AER drivers just sound much more linear altogether than Lowthers. They also extend right the way to 20k with no problem. In fact the treble is the region which is so sweet and resolving on the AERs - I would say it is their absolute forte. I don’t think I heard a violin ever as good as through an AER.

Having owned various AER (BD1, BD2, BD2B, BD3, BD3B) I like to agree on this statement. (never heard BD4 apart from Audio fairs)

 

[spiritofmusic]

Shakti, is there much difference btwn the BD1, 2 and 3? They're much of a muchness on price before you hit the steep climb to BD4.

 

[bonzo75]

Having owned various AER (BD1, BD2, BD2B, BD3, BD3B) I like to agree on this statement. (never heard BD4 apart from Audio fairs)

Bd4 and Bd5 were heard on the same speaker. Given the jump from. 4 to 5, I can imagine 3 to 4 will be high as well. That is also what another Russian user found when he went from Bd3b to 4.

Yes the violin and the highs in them are my favorite but they need to be set up with right amps and cartridge for that.

 

[bonzo75]

Just posted an AER violin video here

Violin videos: solo or with small ensemble

Some Itzahk Perlman

www.whatsbestforum.com

 

[Atmasphere]

I simply avoided Lowthers as i found them too shouty and when you see their breakup in the highs it is easy to know why. The only way i heard them work was with the whizzet removed as in Horning speakers, which I like. I am not sure how AER managed to avoid this without resorting to multiple whizzers like Cube Audio but their measurements suggest they figured it out. Voxativ seems to have at least partially overcome this as well. That said, i haven't heard a single driver whose treble i could live with. I hear some breakup on all of them (even the AERs I have heard at shows). Based on comments about your system, perhaps you have done something that could convince otherwise...

You might want to try the new 6" driver made by PHY. It has no whizzer and pretty smooth response up high. But its also only 96dB. Duke LeJeurne designed a cabinet for this driver for a customer of ours. Duke felt that a pair of tweeters rear firing would help with the off axis beaminess thing that so many 'full range' drivers have and it really did work out quite well. The only downside is this driver only goes to about 70Hz depending on the cabinet. That same customer of ours is currently building a back-loaded horn cabinet for it.

 

[cal3713]

Having owned various AER (BD1, BD2, BD2B, BD3, BD3B) I like to agree on this statement. (never heard BD4 apart from Audio fairs)

Like Marc, I'm also curious about the lower models in the AER line. Is it a linear increase in quality from 1 - 5 or is there an elbow in there somewhere where quality jumps? Obviously there are fabulous reviews of the 4 and 5 drivers...

 

[shakti]

Shakti, is there much difference btwn the BD1, 2 and 3? They're much of a muchness on price before you hit the steep climb to BD4.

With BD1 you get a lot of the AER quality, BD2 is a step better, but I definitely liked the BD3 performance more, which is a bigger step at all.

speakers used with the "B" versions of AER:

Evolution – Highly Sensitive Stereo Horn Speakers – RDacoustic

A unique horn cabinet fitted with extremely sensitive drivers will bring to your home even the tiniest details and perfect spatiality.

rdacoustic.cz

The standard version were fitted Into BD-Design speakers (Oris Horn)

BD4/BD5 might be more designed for bigger Horns like Pnoe

 

[morricab]

With BD1 you get a lot of the AER quality, BD2 is a step better, but I definitely liked the BD3 performance more, which is a bigger step at all.

speakers used with the "B" versions of AER:

Evolution – Highly Sensitive Stereo Horn Speakers – RDacoustic

A unique horn cabinet fitted with extremely sensitive drivers will bring to your home even the tiniest details and perfect spatiality.

rdacoustic.cz

The standard version were fitted Into BD-Design speakers (Oris Horn)

BD4/BD5 might be more designed for bigger Horns like Pnoe

Did you have the RD Acoustics horns? I heard these in Munich and almost bought a pair on the spot! Interestingly, they were getting better sound overall at the show with an inexpensive pair of Fostex drivers than with much more expensive Voxativ. Yes the Voxativ were smoother and more refined but the Fostex drivers had grunt and most importantly BASS.

I would be curious to get a pair of the AERs into a TQWT cabinet for bass loading. This is a much more compact and simple horn concept (it also has elements of reflex loading so it is kind of a "hybrid" horn). You get the speed and texture of horns but with much deeper bass for a given cabinet size and out of drivers that normally make no bass at all (Like my Supravox drivers). Based on the technical data, the standard high sensitivity AERs are very similar to my Supravox 215-2000 drivers, with a very low Qts. Since my drivers work brilliantly in a TQWT (I get flat to 30Hz in room response) I am guessing the normal AER should work great as well...no need to go to the B version.

Has anyone tried the AERs in a TQWT loading? Cube audio loves this design as well (their Nenuphar is a TQWT) as does Horning (they have a double TQWT, which is loaded by the Lowther in the front and the Beyma drivers on the back) and both have great bass.

 

[Audiophile Bill]

Did you have the RD Acoustics horns? I heard these in Munich and almost bought a pair on the spot! Interestingly, they were getting better sound overall at the show with an inexpensive pair of Fostex drivers than with much more expensive Voxativ. Yes the Voxativ were smoother and more refined but the Fostex drivers had grunt and most importantly BASS.

I would be curious to get a pair of the AERs into a TQWT cabinet for bass loading. This is a much more compact and simple horn concept (it also has elements of reflex loading so it is kind of a "hybrid" horn). You get the speed and texture of horns but with much deeper bass for a given cabinet size and out of drivers that normally make no bass at all (Like my Supravox drivers). Based on the technical data, the standard high sensitivity AERs are very similar to my Supravox 215-2000 drivers, with a very low Qts. Since my drivers work brilliantly in a TQWT (I get flat to 30Hz in room response) I am guessing the normal AER should work great as well...no need to go to the B version.

Has anyone tried the AERs in a TQWT loading? Cube audio loves this design as well (their Nenuphar is a TQWT) as does Horning (they have a double TQWT, which is loaded by the Lowther in the front and the Beyma drivers on the back) and both have great bass.

Hi Brad,

Not tried TQWT on the AERs but I am sure they fill work well in that type of application tbh.

That said, I believe this is where the flexibility of the field coil approach can really come into its own. You really can adjust the amount of bass your are getting (at expensive of sensitivity I might add) by changing (lowering) voltage.

My Russian engineer friend keeps telling me not to go making the mistake of chasing Tesla as he is sure I will end up preferring middle of the road voltage rather than a super sensitive and highly damped one. Anyway - will report back soon enough.

 

[morricab]

Hi Brad,

Not tried TQWT on the AERs but I am sure they fill work well in that type of application tbh.

That said, I believe this is where the flexibility of the field coil approach can really come into its own. You really can adjust the amount of bass your are getting (at expensive of sensitivity I might add) by changing (lowering) voltage.

My Russian engineer friend keeps telling me not to go making the mistake of chasing Tesla as he is sure I will end up preferring middle of the road voltage rather than a super sensitive and highly damped one. Anyway - will report back soon enough.

Hi Bill,
Yes, that would be an interesting experiment...perhaps I will look for a pair of Supravox 215-EXC field coil drivers and pop those in to see what they do and how the performance can be adjusted. They are not cheap but quite a bit more affordable than AER drivers or the upper Voxativ drivers.

 

[Audiophile Bill]

Hi Bill,
Yes, that would be an interesting experiment...perhaps I will look for a pair of Supravox 215-EXC field coil drivers and pop those in to see what they do and how the performance can be adjusted. They are not cheap but quite a bit more affordable than AER drivers or the upper Voxativ drivers.

Supravox very handily supply T/S parameters at different voltages so super useful for simulations also…

 

[spiritofmusic]

So Bill, these variable settings could alter efficiency over maybe 7-8dB? To allow a lower setting like 101dB and medium power SETs like 211s, and a higher setting like 107dB+ w low power 46s or 45s?

 

[Audiophile Bill]

So Bill, these variable settings could alter efficiency over maybe 7-8dB? To allow a lower setting like 101dB and medium power SETs like 211s, and a higher setting like 107dB+ w low power 46s or 45s?

Indeed so - depending which driver is being used.

 

[Audiophile Bill]

Marc - for say the Supravox the driver - it varies from 93-102dB sensitivity *without* horn loading depending on voltage applied.