Thanks - I've very much enjoyed the topic. 
In the spirit of never giving up, here's more info on sensitivity etc. for the E70 kit drivers.
ET/02/1 (Tweeter): 8 ohm nominal (6.9 ohm DCR), 98db/2.83V/m, 2.7kHz res.
EM/01/1 (Mid): 8 ohm nominal (4.6 ohm DCR), 94 dB/2.83V/m, 150Hz res.
EB/25/1 (Bass): 8 ohm nominal (4.4 ohm DCR), 95dB/2.83V/m, 42Hz res.
I hope these figures will help clarify the challenges you face in cloning an E70.
In the spirit of never giving up, here's more info on sensitivity etc. for the E70 kit drivers.
ET/02/1 (Tweeter): 8 ohm nominal (6.9 ohm DCR), 98db/2.83V/m, 2.7kHz res.
EM/01/1 (Mid): 8 ohm nominal (4.6 ohm DCR), 94 dB/2.83V/m, 150Hz res.
EB/25/1 (Bass): 8 ohm nominal (4.4 ohm DCR), 95dB/2.83V/m, 42Hz res.
I hope these figures will help clarify the challenges you face in cloning an E70.
Here's a possible mid
Fostex FE 126 En - Fullrange buy at hifisound.de
I would use just one in the bottom position and put the horn in the top position. Saves you one piece of plastic drainpipe to act as mid enclosure.
You might be able to get away without the horn too.
Else use 2 of these in series
Fostex FE 108 EZ Sigma Fullrange buy at hifisound.de
Check for size & fit
Fostex FE 126 En - Fullrange buy at hifisound.de
I would use just one in the bottom position and put the horn in the top position. Saves you one piece of plastic drainpipe to act as mid enclosure.
You might be able to get away without the horn too.
Else use 2 of these in series
Fostex FE 108 EZ Sigma Fullrange buy at hifisound.de
Check for size & fit
Thanks - I've very much enjoyed the topic.
In the spirit of never giving up, here's more info on sensitivity etc. for the E70 kit drivers.
ET/02/1 (Tweeter): 8 ohm nominal (6.9 ohm DCR), 98db/2.83V/m, 2.7kHz res.
EM/01/1 (Mid): 8 ohm nominal (4.6 ohm DCR), 94 dB/2.83V/m, 150Hz res.
EB/25/1 (Bass): 8 ohm nominal (4.4 ohm DCR), 95dB/2.83V/m, 42Hz res.
I hope these figures will help clarify the challenges you face in cloning an E70.
Thanks again. It all helps.
I was going back over my notes and your posts and found this:
"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 1k-5kHz ... if you use a single '8R' nominal
unit with Re 6R4. The originals were 3R2 and connected in series so
more like 98dB/2.83V. May be easier to source a single '8R' unit."
In the Wharfedale data I have found it shows the pair of mids as 8ohms nominal and wired in series. This adding up to 16ohms? Your figure of 3R2 per driver coupled with a high SPL seems to be the target I am looking for.
I assume you posted links to 2 examples as food for thought. The second one with the 4" cones work out at €600+ Postage per set so would be near the price of a tatty second hand pair of actual E70s.
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I have been researching different drivers and as you say, there is virtually nothing out there with 93db+ in a 4". So I looked into 5-6" full range. You can find a few with good output 93-98db but the Fr seems to top out below or too close to the 7000hz E70 design crossover point., and of course they are mega expensive.
Sorry. That should be 3R2 and connected in series at 98dB/2.83V
[QUOTE] In the Wharfedale data I have found it shows the pair of mids as 8ohms nominal and wired in series. This adding up to 16ohms? Your figure of 3R2 per driver coupled with a high SPL seems to be the target I am looking for.
I assume you posted links to 2 examples as food for thought. The second one with the 4" cones work out at €600+ Postage per set so would be near the price of a tatty second hand pair of actual E70s.
[/QUOTE]The spec that Galu posted for the 8R nominal mid is likely for the E50. This was even more sophisticated (& $$$) than the E70 mid cos 1 unit was doing the job of 2.
Fostex FE 126 En - Fullrange buy at hifisound.de
is the closest match I've found for a single mid version from the Fostex range and also from
Loudspeaker Raw Driver Measurements
You may have better luck looking at Car speakers. Don't worry about fr etc. Just get the 94dB/2.83V/1m sens.
To avoid confusion, note that I have been talking about the Wharfedale Speakercraft drivers. The same EM/10/1 mid driver was employed in all three kit speakers (E50, E70 & E90). The commercially produced models differ and I bow to kgrlee's superior knowledge in that respect.
For the record I'll add the following information:
- In the E50 kit, the single EM/10/1 mid has a crossover consisting of a series 16uF and 0.8mH in front of a parallel 8 uF.
- In the E70 kit, the two series EM/10/1 mids have a crossover consisting of a series 16uF and 0.5mH in front of a parallel 4.7uF.
To avoid confusion, note that I have been talking about the Wharfedale Speakercraft drivers. The same EM/10/1 mid driver was employed in all three kit speakers (E50, E70 & E90). The commercially produced models differ and I bow to kgrlee's superior knowledge in that respect.
In the E50 kit, the single EM/10/1 mid has a crossover consisting of a series 16uF and 0.8mH in front of a parallel 8 uF.
- In the E70 kit, the two series EM/10/1 mids have a crossover consisting of a series 16uF and 0.5mH in front of a parallel 4.7uF.
There are good car speakers as well as bad .. as there are good 'hifi' units and bad.
Car speakers are cheaper cos they are made in HUGE numbers. Some customers/manufacturers have very high QC standards. Gold Peak, the company that now owns both KEF & Celestion, has factories in Sam Chan and I remember discussing this with one of their factory managers and their R&D people. If I was starting speakers again, these are the people I would want to make them.
Look for nice 'smooth' frequency responses and the 94dB/2.83V/1m sens. Many 'full range' units may be less sensitive but have our required 94dB in the 1-5kHz range so look at the curves for eg 92dB/2.83V/1m units too.
OK.
I have given it my best shot. I spent most of yesterday searching through long lists of drivers and can't get close enough to required specs, regardless of price.
4", 4ohms, 92db+, reasonably flat response, power handling etc. So at this point I must congratulate Graham Banks and the team at Wharfedale that put so much effort into producing the E70. Respect.
I am wondering if I might get away with a cheat as follows. I have been following a different thread on the forum that is discussing series and parallel drivers. It has been stated that you can use four drivers wired in series/parallel to get a 6db gain. That would bring my "unsuitable" mids up to 94db in total. I do have eight of them to play with. Is this a possible solution or just another flight of fancy?
I have given it my best shot. I spent most of yesterday searching through long lists of drivers and can't get close enough to required specs, regardless of price.
4", 4ohms, 92db+, reasonably flat response, power handling etc. So at this point I must congratulate Graham Banks and the team at Wharfedale that put so much effort into producing the E70. Respect.
I am wondering if I might get away with a cheat as follows. I have been following a different thread on the forum that is discussing series and parallel drivers. It has been stated that you can use four drivers wired in series/parallel to get a 6db gain. That would bring my "unsuitable" mids up to 94db in total. I do have eight of them to play with. Is this a possible solution or just another flight of fancy?
If you are going to change the arrangement of drivers, you might as well use a singleI have been following a different thread on the forum that is discussing series and parallel drivers. It has been stated that you can use four drivers wired in series/parallel to get a 6db gain. That would bring my "unsuitable" mids up to 94db in total. I do have eight of them to play with. Is this a possible solution or just another flight of fancy?
Fostex FE 126 En - Fullrange buy at hifisound.de like I suggested.
How are you going to arrange 4 mids?
Another way to get 6dB on top of your mid's basic sensitivity is to use your 2 mids in parallel. That would halve the impedance and the crossover would need serious tweaking to suit.
Are your mids 8R nominal? If they are 4R nominal, the resulting impedance would be 2R and may upset your amp.
I'd say the latter!Is this a possible solution or just another flight of fancy?
Yes they are 4ohm nominal. That's why I thought about putting them in series pairs before going parallel. Using just two in parallel would bring me to that dodgy 2ohm situation.
I had thought to use the four arranged in a tight cluster + arrangement.
I see why you have suggested the Fostex but at €105 the pair delivered they are even further out of reach than the horn tweeters you recommended.
I think I have reached the point of defeat. Until I can get access to more cash the whole project will have to be put on hold. Given the threat of Brexit hanging over our heads we are not even certain if our pensions will be safe. Sincere thanks to all who have contributed. It hasn't brought me to a satisfactory conclusion but it has given me a bit more knowledge and that is never wasted effort.
I gave it a lot of thought and decided to end the project. So many people have advised just building an established proven design. I decided to try the Paul Carmody Tarkus design. Started by ordering the crossover parts from Loudspeaker Freaks in Holland and a month later I have nothing and they don't answer my emails. I now discover they have ripped off quite a few members here. I can't afford to lose even more money chasing my dream so that is an end to it.
Thanks for all your help, guys.
Thanks for all your help, guys.
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