Has anyone heard of the old Wharfdale E70 made back in the 80's?

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#61
#63
I'm very wary of continuing this discussion. Speaker design can't really be done by specs.

But if you still want to have a go ...

  • use the Parts Express : GRS BT3-8. I don't think this is the original which was made by Foster but it looks good from the 'reviews' and is loud enough. There's a long story behind the choice of the Foster which I won't go into.
  • The bass unit needs a very light cone. Mmd < 20gm and a huge magnet for a 10" .. preferably with Re about 4R8
  • I can't really say much about the mids except they have to be loud. You'll note the originals had huge magnets and VERY light cones. You need 95dB/2.83V over 1-5kHz ... if you use a single '8R' nominal unit with Re 6R4. The originals were 3R2 and connected in series so more like 98dB/2.8V. May be easier to source a single '8R' unit. Unfortunately, the mid is probably the big factor in the sound which allows E70 to challenge far more sophisticated speakers on Classical Music. The bass sorta does the pop / rock stuff.
My apologies for being a snob 😀
 
#64
kgrlee said:
I'm very wary of continuing this discussion. Speaker design can't really be done by specs.
Click to expand...
Same here! We are now straying into 'How to Design an E70 From Scratch' territory, a challenging topic for a whole new thread!

I think I got close once when I married a Wharfedale RS/12/DD with the E70 kit tweeter in a 3 cu ft reflex cabinet. However, they required the addition of a Goodmans Hi-Fax 750-P horn driver to really make the midrange sing. :note:
 
#66
kgrlee said:
Old Bones, who recommended this and the drive units to you?

You said in a previous post that you've already got a box built and had tried out what you'd bought and found it wanting. Do you still have the box? Is it close to the original?
Click to expand...

They were not actually recommended to me personally. I studied the images of the drivers the specialist was selling as suitable upgrade/replacements for the original Wharfedale units and bought them from a cheaper source.

I haven't yet built the enclosures. I have guestimated the internal sizes using the external measurements shown on the Wharfedale service sheet. Then assuming a wall thickness of 3/4" it comes to just over 76 litres. Subtracting the volume in the 2 mid driver tubes it comes to about 70 litres which I have assumed was the origin of the model name E70.

So far I just mounted the drivers on a simple open baffle board and wired them up to the xover as a preliminary test. It was this test that I described earlier. The woofer was totally lifeless and the mids and tweets barely made a sound. I was planning to make sure there were no big problems before committing more money and time to building the boxes. I have a lot of woodworking experience from boatbuilding, etc. so will find that the easy part.
 
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#67
kgrlee said:
I'm very wary of continuing this discussion. Speaker design can't really be done by specs.

But if you still want to have a go ...

  • use the Parts Express : GRS BT3-8. I don't think this is the original which was made by Foster but it looks good from the 'reviews' and is loud enough. There's a long story behind the choice of the Foster which I won't go into.
  • The bass unit needs a very light cone. Mmd < 20gm and a huge magnet for a 10" .. preferably with Re about 4R8
  • I can't really say much about the mids except they have to be loud. You'll note the originals had huge magnets and VERY light cones. You need 95dB/2.83V over 1-5kHz ... if you use a single '8R' nominal unit with Re 6R4. The originals were 3R2 and connected in series so more like 98dB/2.8V. May be easier to source a single '8R' unit. Unfortunately, the mid is probably the big factor in the sound which allows E70 to challenge far more sophisticated speakers on Classical Music. The bass sorta does the pop / rock stuff.
My apologies for being a snob 😀
Click to expand...

No apology required my friend. All your comments have been encouraging and useful to me. I have mentioned this project or related issues on a couple of other forums and been met with brick walls. What I am trying to do is impossible without loads of software, test equipment, and years of experience [alledgedly]. I was was told to just build a kit or work from a well documented design (that more often than not uses high end expensive components). The more I meet with this attitude the more I dig my heels in and carry on. Your posts, and those above from others are much appreciated and will help me on my journey.
 
#68
Yes, the 70 refers to the internal volume of 70 litres.

The dimensions of the enclosure plans I posted earlier are based on panels of 15/18mm thickness

The dimensions of the sealed midrange enclosures are not critical. A cardboard tube (at least 3mm thick) or plastic drainpipe is glued into the front panel and is pressing on a thick foam rubber sealing pad on the back. The tube is completely filled with wadding, such that the packing density increases towards the back of the tube.
 
#69
Thanks to all who have contributed to this thread. I am going to carry on with the project. First step will be to build the crossovers from scratch using the simple circuit posted by Steve in post #32 but with amended values confirmed by kgrlee. I have a bit more research to do before sourcing the components, ie. what voltage ratings on capacitors, wattage ratings on resistors, and coil specs apart from the mH number. Most sellers don't list the impedance of their coils so that will largely be guesswork. If I can find a way around the huge shipping charges for the good tweets from Parts Express I will order a pair, otherwise it will be European sourced Eminence APT30 or 80. I don't know how much wattage they need to cope with. The 30 will manage 10w and the 80 will take 35w. Rather than keep coming back to this same thread with "related" questions I will start separate ones elsewhere.
 
#72
Cal Weldon said:
I have a pair of the Foster 49-1166-01's tweeter foster49-1166-01 - Google Search
that would likely be a drop in replacement but when I see the price of the GRS ones it's hardly worth boxing them up if they're anything like the Fosters
Click to expand...

Since doing more research I find that Fosters supplied OEM drivers for other big names. Those you mention were used by Cervwin Vega (?), Wharfedale, and I think the Fane J22 looks like it as well.
If I could get around the 66USD shipping cost of the GRS units to France I'd go for a pair.
 
#74
Wharfdale

There was a company called "the Radio People" in Hong Kong who built cabinets, and sold them with the Wharfdale drivers. I saw a beautiful pair of teak Wharfdale 90's for sale 2 years ago in a store I frequent. They sold for $200. Someone brought them back from Asia when they were stationed there.

They were very large, and had gorgeous grilles. I did not get a chance to hear them in the store though.
 
#76

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#78
Yes, groovy man! 😎

I threw out a Leak badged Super 3 with Alnico magnet during a parts store clearance around 15 years ago. 😱

Because of the Leak badge, I didn't fully realise the value of what I held in my hand! 🙁

At least it wasn't a pair! 🙂
 
#79
BTW, if you are looking for a bass unit to replace the E70 10", look for something like

Mms 31gm
Re 4R8
Bl 11.6 Tm
Sd 330 cm2

Fs 50 Hz or less but the above 4 parameters are the important ones.

Won't match the response 100 - 1k Hz but the bass should be good.
 
#80
Thanks for getting back to this thread. Those specs will help in my search. I have ordered the parts for the crossovers. Hoping I have made the right corrections to the circuit diagram posted in post #32. Strangely the drivers shown are all current Visaton units.
 
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