I will be focusing on the later model diamond V as pictured above , they have a particle board box with double 13mm mdf front baffle giving a hefty and rigid 26mm ,
Earlier ones had a 7 ohm bass unit with 6 ohm tweeter , these can only be recognized by the smooth and very soft rubber dust cap on the bass unit or by looking inside where you should find a 2nd order butterworth crossover with 5.6mfd and 6.8mfd capacitors ,
the other later ones had a 4ohm bass unit with slightly textured and stiffer dust cap and used an 8 ohm tweeter with 2nd order linkwitz filter with 4mfd and 8mfd capacitors ,
soundwise they are different , the earlier ones are warmer and actually sound more like the previous diamond IV that used the same ingredients as the diamond V mk1( using up parts left over from the IV which means the early mkV is actually just a IV ? perhaps ) ,
The later ones are far flatter across the response with a shorter bump in the bass , these are to my ear far easier to live with as the upper bass lift isnt so obvious , pull them away from the rear wall a bit and stick them to heavy stands , Sadly i cant find a point where change over occurred , i have even seen a pair that had one of each , most likely mixed up in an AV system ,
personally i find the plastic fronts are god awful , if you want to mod your diamond V's then it will have to be removed , just use a flat blade screwdriver and gently tease up the sides at about 1/4 of the way down the baffle and then do it again at 3/4,i will post up pics of how to this soon ,
i think they sound better without all the plastic which does have a profound effect on the output when at higher volumes ,the plastic does have a smoothing effect on the sound at lower volumes and helps cure the diffraction that comes from the edges of the driver chassis ,however the minor diffraction from bare baffle is far less intrusive on the sound than the plastic .this becomes evident when the plastic is removed , suddenly percussive instruments start to fill defined spaces within the soundstage whereas with the plastic it is in the same area but not as well etched in the soundscape . the plastic can be refitted if desired ,perhaps with some damping pads or similar added to the inside of the plastic,
the internal wiring should be checked , some had copper plated steel ! , i only noticed this when the internal wires stuck to the magnet when i was refitting the drivers , i would use basic copper wire such as qed 42 or 79 strand but as long as its copper it will be better than the supplied stuff if yours are steel wired .
relieved of their plastic shrouds of doom ,
next i will be adding some stupidly good capacitors to them along with better quality internal wire then i will be covering the front baffle with leather and addressing the baffle edge to farther reduce the diffraction issues ,
once inside you will more than likely find one small sheet of damping wool , i can guarantee its stuffed in the rear of the box and is doing virtually nothing to control internal energy reflection within the box ,
the wadding is a rectangle as in the above pic , cut or tare along the red line , then roll up the two sides toward the red line , slide the wadding into the box with the cut running either side of the cross over , work it up to the top of each side wall of the box then unroll inside the box , it should cover both side panels and the rear and bottom of the box, at this point i add about 30g of real wool wadding directly behind the bass unit to obtain a stuffing density like the lower of the above pics, i have found this delays the onslaught of compression in the lower mid and bass at higher listening levels but you must have very light (or even no) stuffing density running up from the top of bass units rear all the way to the port/vent as these little boxes need all the help they can get below 80hz which is where the port is most active , you should notice a reduction in lower midrange output from the port , cello and viola will be notably cleaner sounding! . it also doesnt hurt to use a bit of sorbothane under the crossover and just snug down the crossover retaining screws , i fit slightly longer and larger screws so it cant vibrate loose but doesnt over compress the sorbothane , you can also pot the crossover with hot glue once you are satisfied with the results of any crossover mods , just sorting the wadding and wiring helps a lot .
i am also exploring the tweeter options as the fitted metal dome has serious beaming issues on axis hence the phase correction device /diffuser that is fitted , i have found that one of seas 25mm soft dome will run happily and smoothly down to the 2.5khz crossover point and will do it within +- 2db all the way to 22khz , albeit with a small change to the high pass circuit to acomodate the 6 ohm impedance , the metal dome measures similarly and stays flat but hits a wall at 19khz then gets all peaks and troughs as most metal domes seem to , it also has a very definite character that colours the sound unacceptably when compared to my other speakers (that cost over 10 times more than the full rrp on these budget wonders ).
I chose to use Claritycaps on these wee speakers , the reason i chose them is i feel they have best balanced nature in use , not too warm and syrupy and not to cold and analytic , they are not cheap but nor are they stupidly expensive ,
above you can see the difference in size , the blue alcap 50v 8mfd +/-10% and the above 230v 8mfd +-3% , they are a bit of mare to get on the boards ,
When you first power up with these caps expect a slightly 2D presentation for the first 50 hours or so depending on power running through them , they will open up over time , you should also get immediate improvements in instrumental detail , timbre and character of individual instruments will be far clearer ,the tweeter will sound far less coloured and sooo much more integrated with the bass unit ! ,, it all gets better and better over time so be patient with them , after this much fiddling i tend to use them as much as poss for about three weeks before i sit and take in the improvements in a critical way , if all is well and i decide to stay with the tweeter's i will start the finishing work .
more soon ;-)
so they have been running for a week or so , everything is happening as expected , soundstage depth has increased massively , generally speaking the sound from them is just bigger and all instruments are now more weighty and present , sibilants and leading edges of instruments which previous to the mods were a bit over done with little weight to back them up are now crisp and well balanced , the sound now has greater dynamic contrast , keep in mind we working with a pair of speakers that can be had for £25 in VGC and less if they are tatty and scruffy ,
the first few seconds of Scott Walker's Tilt was a real ear opener , percussion was hung in the air with quite disarming ease , a touch limited in ultimate scale but way smoother than the alloy dome unit , i did a quick test with my samsung galaxy s6 using spl spectrum app , i will put up a screen grab of the response while playing a Richard Hawley track that is almost pink noise , its not a real response test as the phone mic only works to about 12,000hz but is good enough to get an idea of how well the new tweeter integrates and if its phase is correct for the 2nd order 180deg phase shift ,
the grab shows a near perfect response up to the mic limits of course .
if you want cheap and cheerful tweeters that punch way above their weight then look no farther , these trounce any dome tweeter at the same price
the pink trace is of a 2 second sample from a vintage sydney bechet track that has no real bass or treble to speak of , the red trace is from the instant the freeze was taken so can be ignored , this is not a frequency sweep as usually used , it is real music played for 2 seconds with all frequency peaks added together from a 5 piece band playing but is great for showing up any obvious lumps at the crossover region from incorrect phase etc , as you can see it is almost flat over the 2,500 hz target point , however the pic below taken from the richard hawley track over 2 seconds and summed ,shows that the treble is rolling off slowly and smoothly from the crossover point upward, this was to be expected as the vifa tweeter was padded down quite a bit , around 2-3db too much for the new planar , easily sorted by adjusting the resistors on the high pass filter to lift the tweeter response a touch to level it out, the lift at around 1000hz and again toward 150hz-80hz is reminiscent of a certain well known bbc design and is often seen in small cheap speakers to give the impression of warmth or 'weight' to the sound , the 1khz bump is chosen to bring the impression of greater clarity , however these anomalies are minor and the bass bump can be tailored
there is a small issue with the bass as mentioned above, for some reason wharfedale have designed in a lift at 150hz (or neglected to attempt to tailor it ), i know it is done for the the reasons above but it can be overcome by blocking the port which reduces the blip by at least half and also rolls off the bass more slowly , but this little driver needs to breath or the mid band can sound a touch restricted , however it can be overcome by making a tapered 1/4 wave box tuned to around 50hz , if you aren't looking for high volumes then this is the best approach , even though the drivers aren't really ideal for it they do seem to respond well to such loading but lose sensitivity , expect 82-84db@1w@1m , the tweeter will need padded down by around 10db from raw but could be as little as 8 or as much as 12 depending on the listener , room etc, i will be aiming for as flat as i can get , the TQW also smooths the 1000hz bump a bit too , i suspect the small box of the diamond does enhance this frequency range a bit , the power handling is good though so will be plenty loud enough in small to medium rooms with a good 50 watt amp . if you do for the TQW remember the driver is not ideal for it and the cone can reach its end stops pretty quickly , recognisable as a 'crack' sound . i will post info about the TQW once i find a suitable recipe .
in the mean time i will just lengthen the port to apply more damping , its against the rules but it does work to smooth out the 150hz bump which is more obvious when the alloy dome tweeter is replaced with such an even handed unit as the planar ,
more soon
