the BL would be an indicator, especially if voice coil length is known...or use a flux capacitor...err fluxmeter ;-)
Field Coils for Audio Systems
- Thread starter Audiophile Bill
- Start date
I am going to buy a gaussmeter actually - can get them for reasonable money now.
I am no expert on this but found the following on the web:
A fluxmeter is therefore different from a gaussmeter in two major ways. First, the fluxmeter measures total flux (?) over an area, where the gaussmeter measures flux density (B) at a single, small, point in space.
cool, thanks! Now that is a major difference! You want to knof flux density in the gap not the total flux!
I found a dealer in the UK willing to give me a trade in on my Altec A7's for some Supravox field coil speakers, but says once ordered there is no back out. I have heard some on YouTube, hard to say if clarity on computer speakers is pure magic on high fi, or harsh noise that gets to one after awhile. Are you able to give some insight here?
Sorry, didn't see that yours are possibly Alnico 215-2000, not Excitation (field coils) 215-2000's?
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I have the Supravox 285-2000 EXC in my upper bass horns (60-600Hz). They blend seamlessly with the midrange. How they sound will be highly dependent on the enclosure, crossover, etc… so not sure what you are asking @Rensselaer?
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I have the 215-2000 Alnico drivers mated to a Beyma CP755TI compression driver in 18 Sound XT1464 horns. Soon I will have solid wood Tractrix horns to try with them. The Supravox is in a TQWT cabinet.
There's an app for that.
I have Keuwlsoft Gaussmeter. Accuracy depends on the phone, so idk about that but it does work.
How can a smartphone measure magnetic fields without a device? It cannot.There's an app for that.
There's an app for that.
As we have local accurate data on the Earth magnetic field we can easily check the calibration of our cellphones. I was astonished to find mine to be accurate within 2%!
I also have found that many inexpensive hall effect sensors are very accurate.
Just tried the app, and it does seem to do SOMETHING...my phone never 'stuck'to metal parts but it does using the app and I get readings that differe when approaching metal versus magnets...not sure if it has any merit but it seems to show variations in magnetism somehow
It looks like they are in a TQWT, for which they are ideal. I have run mine fullrange but they are just not extended enough in the highs and you have to sit with your head in a vice to get acceptable highs. I am basing my DIY design on this model from Supravox:
ALIZEE - Pair of TQWT loudspeakers 2x20W / 99dB
Thanks to its long-standing work on loudspeakers, Supravox engineers design most of their loudspeakers without using a filter, which is the best solution to obtain an exceptional and natural sound reproduction. This TQWT (Tapered Quarter Wave Tube) loudspeaker is a full-range loudspeaker...
www.supravox.fr
In room response is down flat to 35Hz and useful to 30Hz. I found I prefer a compression driver above 1Khz-20Khz. When tuned correctly I get within +-2db from about 200hz-18Khz.
![IMG_0018[1].JPG](https://www.whatsbestforum.com/data/attachments/89/89077-ee38875c9f5911f74aa6f2950617265c.jpg "IMG_0018[1].JPG")
Do I understand correctly that you are not familiar with the field coil speakers I posted but are explaining the high frequency issues with ferrite/Alnico magnet speakers they sell? Have you heard these?It looks like they are in a TQWT, for which they are ideal. I have run mine fullrange but they are just not extended enough in the highs and you have to sit with your head in a vice to get acceptable highs. I am basing my DIY design on this model from Supravox:
ALIZEE - Pair of TQWT loudspeakers 2x20W / 99dB
Thanks to its long-standing work on loudspeakers, Supravox engineers design most of their loudspeakers without using a filter, which is the best solution to obtain an exceptional and natural sound reproduction. This TQWT (Tapered Quarter Wave Tube) loudspeaker is a full-range loudspeaker...www.supravox.fr
In room response is down flat to 35Hz and useful to 30Hz. I found I prefer a compression driver above 1Khz-20Khz. When tuned correctly I get within +-2db from about 200hz-18Khz.
View attachment 98603
Have I heard the field coil 215-2000 exc? No I haven’t but cone geometry and design is identical other than magnet so, while exc version might sound more pure in some way, the high frequency extension shouldn’t change. I can tell you that the bass quality and punch from this driver is very good in a TQWT cabinet (the guy in the video used Supravox designed cabinet just like mine).
It is not issues per se, it’s just physics. An 8 inch driver will beam like hell at high frequencies. It’s fine for some and at least it isn’t nasty in the highs like most Fulleange drivers with a Whizzer cone.
Look at the Cessaro Opus-1 speaker. They have their own version of the Supravox 215-2000 Alnico (they still use the original in the Wagner) and they also choose to match it with a horn tweeter (same with Wagner). A good compression driver to my ears just sounds more realistic up top in a good horn (probably where your ALTECs are letdown).
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