Hi all, i have recently just refurbished some old Wharfedale speakers i had lieing in the attic from the late 70s. They are Wharfedale Dovedale SP's. They were a 79 model i think and come with 3 way crossover and the well recognised white midrange 4.5" speaker with laser cuttings to reduce resonance. They also have two 6.5" mid/bass drivers and a single tweeter.
Basically i have gone ahead and replaced the tweeters with scanspeak classics of the same impedence and freq response because one of the originals had blown. I have had to replace all the bass drivers with the most similar drivers i could find within my price bracket too. I also went about repairing and upgrading the crossovers and replaced all internal wiring with decent copper stuff.
Now my main question is, can anyone provide me with a calculator or some way of calculating the recommended size of cabinet for the new drivers ive chosen to replace the original ones? The spec of the drivers can be found here:
THE ART OF SOUND PERFECTION BY SEAS - H1215-08 CA18RNX
The speaker cabinets are 55litres a piece and since i have two drivers in each cabinet i think this should be ok; but i am struggling to find any method to calculate the recommended cabinet size when using two drivers in one cabinet.
Btw, just on a side note, originally the wharfedale drivers were 16ohms each wired in parallel to make 8ohm. Currently i have my 8ohm SEAS drivers wired in series with one another, but in parrallel to two 8ohm resistors that are wired in series with each other. Am i right in thinking this should be ok to closely represent the original resistance?
Some help would be appreciated if anyone can provide me with some method of calculating a recommended box volume for these drivers when used together, or perhaps even a different driver i could use.
Thanks in advance,
Andrew.
Basically i have gone ahead and replaced the tweeters with scanspeak classics of the same impedence and freq response because one of the originals had blown. I have had to replace all the bass drivers with the most similar drivers i could find within my price bracket too. I also went about repairing and upgrading the crossovers and replaced all internal wiring with decent copper stuff.
Now my main question is, can anyone provide me with a calculator or some way of calculating the recommended size of cabinet for the new drivers ive chosen to replace the original ones? The spec of the drivers can be found here:
THE ART OF SOUND PERFECTION BY SEAS - H1215-08 CA18RNX
The speaker cabinets are 55litres a piece and since i have two drivers in each cabinet i think this should be ok; but i am struggling to find any method to calculate the recommended cabinet size when using two drivers in one cabinet.
Btw, just on a side note, originally the wharfedale drivers were 16ohms each wired in parallel to make 8ohm. Currently i have my 8ohm SEAS drivers wired in series with one another, but in parrallel to two 8ohm resistors that are wired in series with each other. Am i right in thinking this should be ok to closely represent the original resistance?
Some help would be appreciated if anyone can provide me with some method of calculating a recommended box volume for these drivers when used together, or perhaps even a different driver i could use.
Thanks in advance,
Andrew.
The simple way is faking it! Use the value of one driver but double the the Vas then use that cabinet for two drivers. I the the program also calulate maximum output you put in twise the cone area and twise the wattage. ( Basically you fake a driver as big as the two drivers added together)
Yes the wiring is the proper way of doing it.
However there is a very compliacated interaction btween frequency response, impedance and crossover components so just getting 8 Ohm does not ensure that you have a good accoustic crossover.
You are best of with calibrated microphones and a lot of computer programs for measurements as well as heaps of time and knowledge...
A start is downloading testtones say 1/3 octave intervals and play them over the loudspeaker then you can hear severe dips and peaks. If the crossover is ragged try reversing the midrange. If that does not work add a RC-link to the bassdriver it will flatten the impedence of the driver and thus increase the acoustic slope of the crossover thry this both in forward and reverse
Yes the wiring is the proper way of doing it.
However there is a very compliacated interaction btween frequency response, impedance and crossover components so just getting 8 Ohm does not ensure that you have a good accoustic crossover.
You are best of with calibrated microphones and a lot of computer programs for measurements as well as heaps of time and knowledge...
A start is downloading testtones say 1/3 octave intervals and play them over the loudspeaker then you can hear severe dips and peaks. If the crossover is ragged try reversing the midrange. If that does not work add a RC-link to the bassdriver it will flatten the impedence of the driver and thus increase the acoustic slope of the crossover thry this both in forward and reverse
by the looks of it you are making a new speaker, using the old cabinet.
In practise its not too ideal to choose drivers for an exsisting xover and cabinet.
my best bet would be, if you would use your new drivers, and simply make a proper speaker out of them.
"faking" a driver is actualy a good idea.
Winisd does support multiple driver in same cabinet if you are intrested.
freeware, google it.
As for designing a crossover..
Passive Crossover Network Design
this should do just fine.
just read the article, and do things as suggested.
I would advise to update this thread when you got up to something, so if it has flaws others can spot it and direct you to the better direction.
A link of the datasheet of the
"replaced the tweeters with scanspeak classics of the same impedence and freq response because one of the originals had blown" --> twweter woud be nice too.
I would say maybe You should try a 2.5 way floorstander out of the 4 midbass and 2 tweeters You got.
I would think a new design would get You far superior results than swapping drivers of other than originals into an exsisting design.
In practise its not too ideal to choose drivers for an exsisting xover and cabinet.
my best bet would be, if you would use your new drivers, and simply make a proper speaker out of them.
"faking" a driver is actualy a good idea.
Winisd does support multiple driver in same cabinet if you are intrested.
freeware, google it.
As for designing a crossover..
Passive Crossover Network Design
this should do just fine.
just read the article, and do things as suggested.
I would advise to update this thread when you got up to something, so if it has flaws others can spot it and direct you to the better direction.
A link of the datasheet of the
"replaced the tweeters with scanspeak classics of the same impedence and freq response because one of the originals had blown" --> twweter woud be nice too.
I would say maybe You should try a 2.5 way floorstander out of the 4 midbass and 2 tweeters You got.
I would think a new design would get You far superior results than swapping drivers of other than originals into an exsisting design.
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