Hello
Recently I could pick up two vintage Goodmans Woofers as well as other components from an old estate.
Id like to build a new enclosure, as the speakers were mounted in the furniture and did not come with a cabinet.
Tested the woofer in free air and some 140 L sealed enclosure that was lying around, to check them. The go up to 4-5 kHz, are very! sensitive but are difficult the get any deep bass from.
They seem to be very special model with very high BL and very low Qes. Id like to hear about any experience with high BL / low Qes Drivers anyone had.
Some info on the woofer
Goodmans Audiom 852
Size 12 inch, 313mm overall diameter
Weight 26 lbs, 11.8 kg (heaviest 12'' speaker I ever laid hands on)
Total flux 308000 Maxwells (highest number I've ever seen)
Fs 35 Hz
Re 15.8 Ohm and 15.6 Ohm (Highest I ever measured)
3'' voice coil
By comparing with other modells, 308000 Maxwells would correspond with 16'000 Gauss flux density. Taking in account the Re and comparing with other Goodmans woofers I would estimate a BL of around 32.
Does anyone have experience with such woofers?
Thanks a lot for any info.
Martin
Recently I could pick up two vintage Goodmans Woofers as well as other components from an old estate.
Id like to build a new enclosure, as the speakers were mounted in the furniture and did not come with a cabinet.
Tested the woofer in free air and some 140 L sealed enclosure that was lying around, to check them. The go up to 4-5 kHz, are very! sensitive but are difficult the get any deep bass from.
They seem to be very special model with very high BL and very low Qes. Id like to hear about any experience with high BL / low Qes Drivers anyone had.
Some info on the woofer
Goodmans Audiom 852
Size 12 inch, 313mm overall diameter
Weight 26 lbs, 11.8 kg (heaviest 12'' speaker I ever laid hands on)
Total flux 308000 Maxwells (highest number I've ever seen)
Fs 35 Hz
Re 15.8 Ohm and 15.6 Ohm (Highest I ever measured)
3'' voice coil
By comparing with other modells, 308000 Maxwells would correspond with 16'000 Gauss flux density. Taking in account the Re and comparing with other Goodmans woofers I would estimate a BL of around 32.
Does anyone have experience with such woofers?
Thanks a lot for any info.
Martin
Attachments
Hallo Martin
Nice find !
I'd say the best would be to measure the TSPs and design a reflex box from these TSPs. Alternatively you may also be content with a large closed box but that would have less LF headroom. What do you want to drive them with and what kind of music do you listen to usually ?
Regards
Charles
Nice find !
I'd say the best would be to measure the TSPs and design a reflex box from these TSPs. Alternatively you may also be content with a large closed box but that would have less LF headroom. What do you want to drive them with and what kind of music do you listen to usually ?
Regards
Charles
If you don't measure woofers on a regular basis this can be done cheaper by using a signal generator and a voltmeter. Many of the free speaker mesurement programs have a signal generator function.
Regard
Charles
Regard
Charles
Hi Martin,
Why just you don't build an enclosure with same internal volume as that of the furniture? The baffle is in excellent condition as it looks like. Or it's not yours?
Regards,
Dorin
Why just you don't build an enclosure with same internal volume as that of the furniture? The baffle is in excellent condition as it looks like. Or it's not yours?
Regards,
Dorin
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Hi Dorin
Unfortunately, I could not take the baffle with me, it stayed with the old furniture. The speaker had already been disassembled when i got them.
I listen to all kind of music, from renaissance consort, baroque, classic, rock to pop, with the exception of newer things. From solo instruments, over opera to synphonic orchestra and piano concerts.
I'd like to drive them with some low power tube gear. I've built a 10 w class A tube amp that i could use.
Goodmans used the ARU 172 devices in a 7900 cu inch enclosure with those woofers, but they cannot be found easily.
I first thought about some backloaded horn or a TQWT, but have so far no expericence with them.
Martin
Unfortunately, I could not take the baffle with me, it stayed with the old furniture. The speaker had already been disassembled when i got them.
I listen to all kind of music, from renaissance consort, baroque, classic, rock to pop, with the exception of newer things. From solo instruments, over opera to synphonic orchestra and piano concerts.
I'd like to drive them with some low power tube gear. I've built a 10 w class A tube amp that i could use.
Goodmans used the ARU 172 devices in a 7900 cu inch enclosure with those woofers, but they cannot be found easily.
I first thought about some backloaded horn or a TQWT, but have so far no expericence with them.
Martin
If the drivers have very high BL, they're likely to have very low Qts, which makes it hard to get low bass in anything other than an EBS alignment, and that's likely to require a very large box.
Hi Martin, for most of the music genres listed, you don't need much more bass extension other than what this woofer is offering. Build the biggest enclosure you can manage and maybe lately add a cheap subwooofer or two if is it really necessary.
I wouldn't go for a backloaded horn either. And yes, this driver will have quite a low Qes but maybe not as low as some imagine.
Keep in mind that it is a 16 Ohm driver. Drivers with higher impedance usually have more windings. I.e. the L of the BxL rises with higher nominal impedance for a given magnet assembly and coil size. You can check this easily from manufacturer data sheets of drivers that can be had in different nominal impedance versions.
If you don't listen to EDM and Hip Hop you may probably be quite happy with a large closed box.
Regards
Charles
Keep in mind that it is a 16 Ohm driver. Drivers with higher impedance usually have more windings. I.e. the L of the BxL rises with higher nominal impedance for a given magnet assembly and coil size. You can check this easily from manufacturer data sheets of drivers that can be had in different nominal impedance versions.
If you don't listen to EDM and Hip Hop you may probably be quite happy with a large closed box.
Regards
Charles
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