Hello,
i recently acquired a pair of extremely rare Marantz Model M2 'Focused Field' bookshelf speakers and would like to replace the 6.5" bass drivers as the ones they came with are very cheap replacements and the originals are basically impossible to find.
i am a neophyte so please bear with me, and i have attached all i could find after much searching. i hope to gift these to an ailing friend and realize there are some variables to consider, but i am not familiar with the calculations and time is of the essence in this case. i did find something within my budget and, assuming i needed 4ohm drivers, wondered if they might be suitable or if anyone could recommend something better:
6.5" Replacement Speaker Woofer Part # W-6024
Anyway, any suggestions would be greatly appreciated.
Cheers.
i recently acquired a pair of extremely rare Marantz Model M2 'Focused Field' bookshelf speakers and would like to replace the 6.5" bass drivers as the ones they came with are very cheap replacements and the originals are basically impossible to find.
i am a neophyte so please bear with me, and i have attached all i could find after much searching. i hope to gift these to an ailing friend and realize there are some variables to consider, but i am not familiar with the calculations and time is of the essence in this case. i did find something within my budget and, assuming i needed 4ohm drivers, wondered if they might be suitable or if anyone could recommend something better:
6.5" Replacement Speaker Woofer Part # W-6024
- Steel Frame
- Poly Mica Cone, Rubber Surround, Vented, Bumped Backplate
- Size: 6.5"
- Hole cut-out: 5.625"
- Depth: 3.25"
- Voice Coil: 1.5"
- Magnet: 20 oz
- Impedance: 4 ohms, Re: 3.6 ohms
- Power: 90 watts RMS, 170 watts max
- Response: 29-4800 Hz
- Sensitivity: 85 dB, 1 watt, 1 meter
- Le: .40 mH, Fs: 58 Hz, Vas: .42 cu. ft., Qms: 3.05, Qes: .71, Qts: .57, Xmax: 4mm
Anyway, any suggestions would be greatly appreciated.
Cheers.
Attachments
Maybe a Scan speak 18W/4424G00 would fit with a little work and has a response that should allow you work up a Xover if you have measurement capability and can use a Xover design package.
I haven't checked the SB acoustics website maybe their 6.5 Polypropylene 4ohm driver would work. Although its dimensions are slightly smaller .
As to its T/S params you will need to go over them to see if they are in the ballpark. Both drivers can be made to work at a 2.5K Xover. I don't know how they will perform in the bass if it is a sealed cabinet?
I do not know if your Marantz is a vented design. If so Both drivers would work,. If sealed the Scan maybe give a little more bass for the box size.
Actually the Peerless SDS 830657 6.5 inch driver may be a cheap and effective quick fix however its 8 Ohms impedance which would mean a redesign the bass portion of the Xover. I Imagine it all comes down to how much time and effort you want to put into this.
I haven't checked the SB acoustics website maybe their 6.5 Polypropylene 4ohm driver would work. Although its dimensions are slightly smaller .
As to its T/S params you will need to go over them to see if they are in the ballpark. Both drivers can be made to work at a 2.5K Xover. I don't know how they will perform in the bass if it is a sealed cabinet?
I do not know if your Marantz is a vented design. If so Both drivers would work,. If sealed the Scan maybe give a little more bass for the box size.
Actually the Peerless SDS 830657 6.5 inch driver may be a cheap and effective quick fix however its 8 Ohms impedance which would mean a redesign the bass portion of the Xover. I Imagine it all comes down to how much time and effort you want to put into this.
I Googled the part number in your post and came up with an online listing for US$48 each as the first hit. I assume that's the driver in your speaker? Not particularly cheap and there will be much better woofers for that price if that's the case.
Whatever you choose, even if it physically fits it almost certainly won't have the same sound and frequency response, etc as the original part, or indeed the replacement part, so a new crossover would be needed. to get it to sound good.
Parts Express used to have a woofer selection guide which listed the parameters, dimensions etc so you could compare drivers. Might not still be there, but might be worth an optic.
What do they sound like?
Geoff
Whatever you choose, even if it physically fits it almost certainly won't have the same sound and frequency response, etc as the original part, or indeed the replacement part, so a new crossover would be needed. to get it to sound good.
Parts Express used to have a woofer selection guide which listed the parameters, dimensions etc so you could compare drivers. Might not still be there, but might be worth an optic.
What do they sound like?
Geoff
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Thanks. The existing drivers are not original and poor quality,low power substitutes. The stock Marantz drivers for these i believe are virtually impossible to find in any condition. i have looked for some time and found nothing on the particular model except the odd thread (including mine).
The part number i listed is what i for one i considered using a possible replacement. The ones that came with it are of a low quality and power rating.
The part number i listed is what i for one i considered using a possible replacement. The ones that came with it are of a low quality and power rating.
If you were to buy that woofer, it would cost you US$96 plus shipping, plus a new crossover and you don't know if it's a good sounding woofer anyway.
For that damage, you might be better of looking at an existing two way project for which that sealed box size (about 12 litres) might work for you. Something with Peerless, Dayton, SB Acoustics or Vifa drivers - low cost but good performers.
There would still be the rather important issue of finding drivers which fit, unless you particularly want to perform surgery on the baffle. Could you please let us know the measurements of the cut outs and rebates in your cabinets? Are the dimensions of the possible replacement woofer the same as what you have - if so, we could work with those but we'd still need those details for the tweeter, assuming you want to go down that path.
Geoff
For that damage, you might be better of looking at an existing two way project for which that sealed box size (about 12 litres) might work for you. Something with Peerless, Dayton, SB Acoustics or Vifa drivers - low cost but good performers.
There would still be the rather important issue of finding drivers which fit, unless you particularly want to perform surgery on the baffle. Could you please let us know the measurements of the cut outs and rebates in your cabinets? Are the dimensions of the possible replacement woofer the same as what you have - if so, we could work with those but we'd still need those details for the tweeter, assuming you want to go down that path.
Geoff
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Thanks for the reply.
Unfortunately, i do not have much time at the moment to research design. i just wondered if there happened to be someone in the forum who might know of a driver that would be a (more) suitable swap-out based on the attachments, which contain the speaker's dims/specs, The driver i was considering seems to fit the opening and has a good bottom end and fairly high power rating for the size.
Unfortunately, i do not have much time at the moment to research design. i just wondered if there happened to be someone in the forum who might know of a driver that would be a (more) suitable swap-out based on the attachments, which contain the speaker's dims/specs, The driver i was considering seems to fit the opening and has a good bottom end and fairly high power rating for the size.
They don't make midwoofers with anything like these kind of specs (for closed box in 4ohms) anymore. You may find any number of things that fit the cutout, but the likelihood that the acoustic response of the replacement with the existing crossover filter will still match anywhere close the original design is almost zero. Closest I could think of that has anything remotely close to the original specs and is still available, is the 8ohm Seas CA18RLY.
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I has a quick optic at various drivers; there are some 4 ohm rated drivers which would fit the cut out, such as the SB16pfcr-4 and Dayton DC160-4, but the specs such as dB, QTS and FS are different, sometimes markedly, and that's without considering the sound. I haven't seen any sealed cabinet projects for your sized cabinet and those drivers, so I don't know how they might perform in that situation.
Of the two, the SB is higher quality, more expensive, higher efficiency and has better mid-range than the Dayton, IMHO. It would also better suit the brochure's stated XO point of 2400Hz.
A Peerless 830657, which can be surface mounted, would be cheap and could work in that size sealed cabinet (I think, someone please correct me if not) , but it's an 8 ohm woofer so the crossover would have to change anyway. Not many two way projects for it, although I've done one with a Vifa BC25TG tweeter. Driver cost in Canada for that one would probably be around the same as the woofers in your initial post.
Geoff
Of the two, the SB is higher quality, more expensive, higher efficiency and has better mid-range than the Dayton, IMHO. It would also better suit the brochure's stated XO point of 2400Hz.
A Peerless 830657, which can be surface mounted, would be cheap and could work in that size sealed cabinet (I think, someone please correct me if not) , but it's an 8 ohm woofer so the crossover would have to change anyway. Not many two way projects for it, although I've done one with a Vifa BC25TG tweeter. Driver cost in Canada for that one would probably be around the same as the woofers in your initial post.
Geoff
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If it is possible, look for speakers on sale, the ones I got in the flea market locally were with mild cabinet damage, working, Philips India 2 and 3 way units, 100 Rupees - $1.25 - each.
You can give those to your friend for his/her entertainment.
I think it is less effort than repairing what is really a once repaired unit.
And your speaker is a 2 way design, so it is a full range + tweeter in my opinion, the big speaker is not a woofer.
Look for Chinese or Parts Express parts, Scan Speak are really Chinese parts assembled in Denmark, so quite expensive for what it inside.
It may be a lot of work, you may not like how the replacement drivers sound like, hole may not match and so on...it may cost you more than what you may have expected, shipment is costly nowadays.
If I had the original drivers, I can get them rebuilt with new cones and coils here quite cheaply, but in Canada, that is difficult.
You can give those to your friend for his/her entertainment.
I think it is less effort than repairing what is really a once repaired unit.
And your speaker is a 2 way design, so it is a full range + tweeter in my opinion, the big speaker is not a woofer.
Look for Chinese or Parts Express parts, Scan Speak are really Chinese parts assembled in Denmark, so quite expensive for what it inside.
It may be a lot of work, you may not like how the replacement drivers sound like, hole may not match and so on...it may cost you more than what you may have expected, shipment is costly nowadays.
If I had the original drivers, I can get them rebuilt with new cones and coils here quite cheaply, but in Canada, that is difficult.
The replacement drivers it came with i believe are inexpensive, low power and 8ohms. They sounded weak and muddy. These are so very rare. i have only found one thread describing their sound and, according to that review, they are quite good. Don't find too many small boxes claiming to reach down to 30Hz. Would love to find a pair of original bass drivers, but searching part numbers produces nothing and the likelihood of finding a pair of loose ones in any condition is not.
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