Hi folks
I’ve done a lot of reading of past threads but thought it best to simply post a thread to the good people here.
I somewhat recently inherited a few speakers from my late father, which have led me through a nice pathway of learning a little about restoring and tinkering with speakers.
A Wharfedale Teesdale (the omni-directional 3-way) which sympathetically recapped sounds really lovely even in its mono state.
Kef Celeste IVs which after a recap, and some painting of butyl on the degraded tweeter domes sound quite impressive compared to the apparently crappy Bluetooth speakers I was used to.
The final set are some Denton 2s ….with missing tweeters. By all accounts these little speakers really were not great even in their time, and i suspect 50 years might not have done them any favours. But they were almost certainly his first set so I would ideally want to restore them and keep them around, the enclosures at the very least.
The problem I have is that it’s rather difficult to find an exact set of replacement drivers on the Bay. With an assumption that they are the purple plastic ones, there is likely a need to restore these tweeters too as I have read that they had a tendency to detach themselves , it has been 50 years after all.
Alternatively I was hoping to potentially upgrade the crossover and add a new tweeter - 6ohm, suitable for the 1750Hz crossover point. But there is very little information on woofer specs, and no other builds that i could find to crib from where a tweeter’s been successfully modded into the existing system.
In any case the original crossover design seems odd in comparison to what I normally see documented or suggested.
A 2.0mH, 50uf filter on the woofer, and 0.8mH 16uf for the tweeter/midrange. It seems that without fundamentally redesigning the crossover any dropping of a replacement driver is probably not going to work well.
I had found a driver that may work, something like the Seas 27TDFC-06 which appears to be a matching impedance and suitable for crossovers down to 1500Hz. Of course it is much more complicated than this, but in theory could this work with the existing crossover whilst retaining the current woofer?
Alternatively (and i suspect this is most sensible) I could simply rebuild a 2-way using the existing cabinet. I believe the internal volume is 12-14L, with no porting - should it be possible to build a reasonably cheap but pleasant enough sounding speaker for the kitchen for an enclosure of these rough specs?
Apologies for the length of the post, hoping that there’s possibly enough to go on from that ramble.
I’ve done a lot of reading of past threads but thought it best to simply post a thread to the good people here.
I somewhat recently inherited a few speakers from my late father, which have led me through a nice pathway of learning a little about restoring and tinkering with speakers.
A Wharfedale Teesdale (the omni-directional 3-way) which sympathetically recapped sounds really lovely even in its mono state.
Kef Celeste IVs which after a recap, and some painting of butyl on the degraded tweeter domes sound quite impressive compared to the apparently crappy Bluetooth speakers I was used to.
The final set are some Denton 2s ….with missing tweeters. By all accounts these little speakers really were not great even in their time, and i suspect 50 years might not have done them any favours. But they were almost certainly his first set so I would ideally want to restore them and keep them around, the enclosures at the very least.
The problem I have is that it’s rather difficult to find an exact set of replacement drivers on the Bay. With an assumption that they are the purple plastic ones, there is likely a need to restore these tweeters too as I have read that they had a tendency to detach themselves , it has been 50 years after all.
Alternatively I was hoping to potentially upgrade the crossover and add a new tweeter - 6ohm, suitable for the 1750Hz crossover point. But there is very little information on woofer specs, and no other builds that i could find to crib from where a tweeter’s been successfully modded into the existing system.
In any case the original crossover design seems odd in comparison to what I normally see documented or suggested.
A 2.0mH, 50uf filter on the woofer, and 0.8mH 16uf for the tweeter/midrange. It seems that without fundamentally redesigning the crossover any dropping of a replacement driver is probably not going to work well.
I had found a driver that may work, something like the Seas 27TDFC-06 which appears to be a matching impedance and suitable for crossovers down to 1500Hz. Of course it is much more complicated than this, but in theory could this work with the existing crossover whilst retaining the current woofer?
Alternatively (and i suspect this is most sensible) I could simply rebuild a 2-way using the existing cabinet. I believe the internal volume is 12-14L, with no porting - should it be possible to build a reasonably cheap but pleasant enough sounding speaker for the kitchen for an enclosure of these rough specs?
Apologies for the length of the post, hoping that there’s possibly enough to go on from that ramble.
Any pictures? Seacrhing comes up with a couple omnis none called Teesdale. The SP2 version with the same name is a more convential 3-way.
If they are these there is a chance i still have a pair kicking around.
dave
There were lots of models of the Wharfedale Denton style.
The old ones had two mounting bolts on the bass, recessed on the baffle and the purple jellyfish tweeter. The back panel was removeable. As in Dave's shot.
Later ones had a front of baffle mounting, a smallish bass and a cone tweeter with a little coffee cup sized enclosure. The crossover was quite low (1750Hz?) and tended to fry the tweeter at parties.
We did find a woofer that might slot in without too much effort the 8" paper bass Monacor SPM-205/8:
https://willys-hifi.com/products/monacor-spm-205-bass-mid-speaker?variant=42205576787
Tweeters are replaceable too, and a 3/4" should work, but would normally be crossed nearer 3kHz. Which means some crossover changes which I can flesh out if you want once you decide on things..
Wilmslow keep crossover components too:
https://wilmslowaudio.co.uk/monacor/monacor-spm-2058-size200x200mm
I think you should see how it all sounds and works and take it from there. Measure cutouts and widths of drivers too if replacing.
Wharfedale did some models with regular tweeters like the Shelton:
https://www.diyaudio.com/community/threads/wharfedale-shelton-xp2-a-minor-classic-imo.314732/
The Wharfedale Laser 90B was another we covered here. Quite a nice filter. The small coil on the tweeter input tames a plastic tweeter.
The 450uF on the bass is optional.
They all look a bit the same after awhile...
Best, Steve.
The old ones had two mounting bolts on the bass, recessed on the baffle and the purple jellyfish tweeter. The back panel was removeable. As in Dave's shot.
Later ones had a front of baffle mounting, a smallish bass and a cone tweeter with a little coffee cup sized enclosure. The crossover was quite low (1750Hz?) and tended to fry the tweeter at parties.
We did find a woofer that might slot in without too much effort the 8" paper bass Monacor SPM-205/8:
https://willys-hifi.com/products/monacor-spm-205-bass-mid-speaker?variant=42205576787
Tweeters are replaceable too, and a 3/4" should work, but would normally be crossed nearer 3kHz. Which means some crossover changes which I can flesh out if you want once you decide on things..
Wilmslow keep crossover components too:
https://wilmslowaudio.co.uk/monacor/monacor-spm-2058-size200x200mm
I think you should see how it all sounds and works and take it from there. Measure cutouts and widths of drivers too if replacing.
Wharfedale did some models with regular tweeters like the Shelton:
https://www.diyaudio.com/community/threads/wharfedale-shelton-xp2-a-minor-classic-imo.314732/
The Wharfedale Laser 90B was another we covered here. Quite a nice filter. The small coil on the tweeter input tames a plastic tweeter.
The 450uF on the bass is optional.
They all look a bit the same after awhile...
Best, Steve.
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Like Lojzek, I see the crossover point of the Denton 2 quoted as 1,400 Hz: https://www.hifiengine.com/manual_library/wharfedale/denton-2.shtml
I have a pair of Denton 2 which belonged to a friend. I've played around with them, recapping/modifying the crossovers etc., but they still sound lacking in excitement.
The best thing about them is their sturdy, teak veneered enclosures, and I've often thought about fitting new drivers and crossovers.
P.S. Wharfedale described the Denton 2 tweeter as a "mid-range treble unit". It has a plastic rear housing described as an "integral loading cavity for minimum distortion in the mid-range". The purple cone is made of Cellulose Acetate Butyrate (CAB) which "combines great strength with light weight".
This is a refurbished pair of Denton 2 that I spotted at auction a while back:
The woofer turned out to be a cheap PA replacement and the tweeter was unspecified.
However, it does indicate what can be achieved appearance wise.
That's the arrangement of my Denton 2 crossovers. I replaced the ageing ELCAP capacitors.
This a photo of one of my Denton 2s:
Thanks for the responses folks, your knowledge is much valued.
I think I may have seen the user manual you mentioned, the frequency response graph looked like the one here: https://www.petervis.com/gallery/Vintage%20Advertisements/wharfedale-hi-fi/wharfedale-denton-2.html
Interesting to see some comparable Wharfedale crossover designs system7, I am thinking perhaps these little speakers were certainly built to meet a price bracket since they're certainly missing some complexity compared to those Sheltons.
Potentially, they mightn't sound all that hot even with sparkly new midrange tweeters, and that would be after tweaking (or more realistically rebuilding the crossover)? In comparison, as you say Galu, the cabinets are really quite robust. I suspect after sanding and refinishing the veneer, and adding a new grill cloth they might look pretty handsome. But maybe I might be polishing a turd, sound-wise...
Having very crudely remeasured the enclosures, they are roughly 15-16L internal volume, potentially a suitable candidate for something resembling the KEF based LS3/5a?
Cheers
Ampoule
Ah, thankyou. Potentially I have been looking for an incorrect driver specification!
I think I may have seen the user manual you mentioned, the frequency response graph looked like the one here: https://www.petervis.com/gallery/Vintage%20Advertisements/wharfedale-hi-fi/wharfedale-denton-2.html
I may have a wire crossed, I have one of the large Teesdales that look like the below image. I believe the aluminium cones in the top half (pictured) were supposed to disperse the sounds from the mid-range driver and tweeter. The enclosures for these definitely warrant the term 'cabinets', quite impressive furniture making going on really.
The model I have is identical to the one posted by Galu (sans tweeters). The 1750Hz crossover frying tweeters might indeed line up with these lacking their drivers!
Interesting to see some comparable Wharfedale crossover designs system7, I am thinking perhaps these little speakers were certainly built to meet a price bracket since they're certainly missing some complexity compared to those Sheltons.
Potentially, they mightn't sound all that hot even with sparkly new midrange tweeters, and that would be after tweaking (or more realistically rebuilding the crossover)? In comparison, as you say Galu, the cabinets are really quite robust. I suspect after sanding and refinishing the veneer, and adding a new grill cloth they might look pretty handsome. But maybe I might be polishing a turd, sound-wise...
Having very crudely remeasured the enclosures, they are roughly 15-16L internal volume, potentially a suitable candidate for something resembling the KEF based LS3/5a?
Cheers
Ampoule
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The KEF LS3/5a has an internal volume of 5.5 L.
Note that the crossover point for the midrange/tweeter (M/T) in the Denton 2 is quoted by several sources as 1,400 Hz.
If you were simply looking to replace the M/T, you'd be looking at a substitute with a resonance frequency at least an octave below that.
A small full range driver, protected at the rear like the original Denton 2 M/T by its own small enclosure, may be a suitable replacement.
Perhaps something like this one from the wide Visaton range: https://www.visaton.de/sites/default/files/dd_product/FR 58_2204_2205.pdf
Thanks for the caution.
What would that figure translate to in dB/m/W I wonder?
Below, for all to see, is the very FR curve you mention:
I see now that I had a brain freeze when looking at its specs! I read 81 dB/W/m as 91 dB/W/m. And that would still not be high enough it would appear!
I am not sure. SPL reduction due distance increase from 0.4m to 1m, about -8dB and power reduction 1.5=-1.76dB.
If they meant 1.5W as 50% voltage increase, then it's -3.52dB. There is no voltage reference and impedance/dcr also unknown.
Thanks for your calculations!
Reading off the graph at 1,000 Hz gives me an SPL of around 96 dB.
According to your calculations we might be justified in subtracting 10 or 12 dB to get the dB/W/m sensitivity figure.
I can't find a system sensitivity figure for the Denton 2, but the later Denton 2XP (XP for extra power) was quoted as 88 dB/W/m - although it did use a different tweeter!
The Visaton FRS 7 (4 or 8 ohm) is quoted at 88 dB/W/m and might prove suitable if its physical dimensions check out.
https://www.visaton.de/sites/default/files/dd_product/FRS 7_2011_2012_0.pdf
However, the protruding circumferential lip at the rear necessitates rear mounting or the use of an adaptor plate.
A pair costs around £25 from cpc: https://cpc.farnell.com/visaton/frs7-2012/speaker-full-range-2-5-15w-8ohm/dp/LS01665
Not too much of a monetary risk! N.B. Must be FRS 7 and not one of its variants.
@Ampoule I hope you haven't fallen asleep by now!
https://www.visaton.de/sites/default/files/dd_product/FRS 7_2011_2012_0.pdf
However, the protruding circumferential lip at the rear necessitates rear mounting or the use of an adaptor plate.
A pair costs around £25 from cpc: https://cpc.farnell.com/visaton/frs7-2012/speaker-full-range-2-5-15w-8ohm/dp/LS01665
Not too much of a monetary risk! N.B. Must be FRS 7 and not one of its variants.
@Ampoule I hope you haven't fallen asleep by now!