I bought a set of Sound Dynamics 12 s speakers a while back and the lady who sold them to me said that the woofers were replaced back in the 90's. I asked if they were replaced by the same Sound Dynamics woofers and she assured me they were. Of course it turns out they weren't (which explains why they didn't sound as efficient/sensitive as I was expecting them to be). The only markings on the replacement woofers is PMBWC1228. They are light and seem of modest quality from what I can tell (they look like coated paper--I'll post a picture of the generic woofers later).
1) Does anyone know anything about the 12" woofer that were used as replacements in my 12s cabinets? They are marked PMBWC1228.
2) I have a set of Sound Dynamics Signature Series s45's with a blown tweeter (these are three ways). Would the 12" woofer in those work in the 12s, or would they likely be deficient in the mid-range?
3) Does anyone know of a viable replacement for the 12" woofers in the Sound Dynamics 12s (which have high sensitivity)?
4) If there is no viable replacement for the 12s woofers, does anyone know of a good way to use the old spun aluminum horn tweeters in the 12s, perhaps an alternative DIY design, for example, that I might try?
Note: Unfortunately I have no idea of the specifications of either the 12s woofers or the spun aluminum horn tweeters, but was hoping someone here might already be familiar with them.
Thanks.
1) Does anyone know anything about the 12" woofer that were used as replacements in my 12s cabinets? They are marked PMBWC1228.
2) I have a set of Sound Dynamics Signature Series s45's with a blown tweeter (these are three ways). Would the 12" woofer in those work in the 12s, or would they likely be deficient in the mid-range?
3) Does anyone know of a viable replacement for the 12" woofers in the Sound Dynamics 12s (which have high sensitivity)?
4) If there is no viable replacement for the 12s woofers, does anyone know of a good way to use the old spun aluminum horn tweeters in the 12s, perhaps an alternative DIY design, for example, that I might try?
Note: Unfortunately I have no idea of the specifications of either the 12s woofers or the spun aluminum horn tweeters, but was hoping someone here might already be familiar with them.
Thanks.
Those yellow/orange surround paper cone woofers you posted on canuck look
like a decent replacement units. Probably made to be sealed. Of course, this has
to be verified by measuring the parameters and response. I suppose they would be
about 88-89 dB in the box with filter on which suits the waveguided tweeter well.
BTW, tweeter looks very good in the waveguide.
like a decent replacement units. Probably made to be sealed. Of course, this has
to be verified by measuring the parameters and response. I suppose they would be
about 88-89 dB in the box with filter on which suits the waveguided tweeter well.
BTW, tweeter looks very good in the waveguide.
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Thanks for the observations. If I knew that the 'orange' woofers were properly matched to the tweeters (and cabinet) I would just continue to use them and be done with it. But they don't seem to be as sensitive as I would expect the 12s to be (which is typically noted as having a sensitivity of 101 or 102 db). They are definitely not as sensitive as the other pair of Sound Dynamics speakers that I own (the sd 45s, which also seem to have a higher sensitivity than the normal range of speakers), which leads me to wonder if the woofers are not properly matched to the tweeters.
For those who haven't seen the pics on the other site Lojzek mentioned, here are a few of the drivers in question.
For those who haven't seen the pics on the other site Lojzek mentioned, here are a few of the drivers in question.
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Philosophil,
The trick is going to find a large woofer that will work in a two way.
This is all I can think of, it is very expensive:
The Madisound Speaker Store
The trick is going to find a large woofer that will work in a two way.
This is all I can think of, it is very expensive:
The Madisound Speaker Store
Hi Phil,
only PA drivers with powerful motors can come close to higher sensitivity
values. No way your SD 45 would ever come anywhere near that, maybe
around 90 db tops. An example of Eminence Beta 12A-2 in100 litre vented
cabinet, low passed. Manufacturer says 98 db,the break-up region exceeds
100 dB, the usable level is rather 94 dB in open space.
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Lozek,
I'm not trying to question your knowledge in these matters, which far exceeds my own, but the Sound Dynamics sd 45s are definitely more sensitive than my PSB 500's (which are rated as 92 sensitivity), for they play much louder at the same volume level than the PSB's do. Also, here's a list of some of the specs of the Sound Dynamics 12s as taken from an ad on US Audio Mart:
* 1" dome aluminum horn tweeters
* 12" woofers
* 10 - 125 W RMS
* 28 - 20000 Hz
* 101 dB/W/m
* 26 1/2 x 15 x 12 "
* 55 lbs EACH
Are these specs inaccurate? Klipsch and Cerwin Vegas often post high sensitivity levels, so couldn't Sound Dynamics be in the same ballpark as these?
I'm not trying to question your knowledge in these matters, which far exceeds my own, but the Sound Dynamics sd 45s are definitely more sensitive than my PSB 500's (which are rated as 92 sensitivity), for they play much louder at the same volume level than the PSB's do. Also, here's a list of some of the specs of the Sound Dynamics 12s as taken from an ad on US Audio Mart:
* 1" dome aluminum horn tweeters
* 12" woofers
* 10 - 125 W RMS
* 28 - 20000 Hz
* 101 dB/W/m
* 26 1/2 x 15 x 12 "
* 55 lbs EACH
Are these specs inaccurate? Klipsch and Cerwin Vegas often post high sensitivity levels, so couldn't Sound Dynamics be in the same ballpark as these?
45's may well be louder than psb's, only this doesn't necessarily mean
they are higher in sensitivity than 92 dB. It would not be the first time
specs were tuned up to the public expectation.
Specs you posted are not very informative for they neither say anything
about the response smoothness, nor about the power level at both the
frequency extremes. 28 Hz can be anything, like -10dB from the rest
of the spectrum. If it's true that it can play bass allright, which I don't doubt,
then there is no way sensitivity can ever be that great. It's only natural.
In order to have high SPL, motor has to be large and powerful and the
suspension pretty stiff which raises the resonant frequency significantly
and causes the Qts to be very low which prevents the driver to passively
play lower bass.
As an example of a speaker specifications presented truthfully, I chose this one:
Abbey
The best you can do to find out how things are is measuring yourself.
they are higher in sensitivity than 92 dB. It would not be the first time
specs were tuned up to the public expectation.
Specs you posted are not very informative for they neither say anything
about the response smoothness, nor about the power level at both the
frequency extremes. 28 Hz can be anything, like -10dB from the rest
of the spectrum. If it's true that it can play bass allright, which I don't doubt,
then there is no way sensitivity can ever be that great. It's only natural.
In order to have high SPL, motor has to be large and powerful and the
suspension pretty stiff which raises the resonant frequency significantly
and causes the Qts to be very low which prevents the driver to passively
play lower bass.
As an example of a speaker specifications presented truthfully, I chose this one:
Abbey
The best you can do to find out how things are is measuring yourself.
Yeah, those replacement 12"s don't look up to much.
What're you going to do for a crossover? - I think this will determine how you proceed.
Chris
What're you going to do for a crossover? - I think this will determine how you proceed.
Chris
Unfortunately, crossovers are well beyond my level of competence. When it comes to this sort of thing I have to depend on the knowledge and expertise of others. I was simply hoping that someone else here may have worked with Sound Dynamics 12s speakers or their tweeters (or those unknown replacement drivers) in the past and might be able to offer me some guidance regarding what options might best be available to me. Sad I know, but unfortunately that's where things stand at my end of things. 🙁
Philosophil,
Are you saying you just want to lower the alum tweeter level to the woofer? That's really easy and inexpensive.
And/or check out this new woofer line - being discussed on another thread - good to 4,000hz!
Dayton Audio PA310-8 12" Pro Woofer
Are you saying you just want to lower the alum tweeter level to the woofer? That's really easy and inexpensive.
And/or check out this new woofer line - being discussed on another thread - good to 4,000hz!
Dayton Audio PA310-8 12" Pro Woofer
While I honestly never thought about lowering the tweeter to the woofer, but I would actually prefer to have woofers that match the tweeters (higher sensitivity). The woofer you linked here actually looks really interesting, so thanks for that.
Hi Phil,
Read this through so you know what a waveguide does to tweeter response.
Although certain frequency region gets amplified, it needs to be brought
down in level for hifi performance.The purpose of a waveguide is controlled
directivity. It could happen to you that a real PA woofer would be too loud for
your tweeter.
Zaph|Audio
Read this through so you know what a waveguide does to tweeter response.
Although certain frequency region gets amplified, it needs to be brought
down in level for hifi performance.The purpose of a waveguide is controlled
directivity. It could happen to you that a real PA woofer would be too loud for
your tweeter.
Zaph|Audio
So am I right in concluding that the waveguide lowers the crossover point for the speaker? Does it also have any effect on off-axis response.
The horn tweeters in those 12s have what appears to be an L-pad at the rear of the cabinet. How would this relate to lowering the tweeter to match the woofer (in the current set up I find them a little harsh when turned up, and better when turned down).
Okay, so another quick scan of that article suggests that waveguides increase efficiency within a certain frequency range, and also increases directivity. When the frequency range is tamed with a filter the general result is lower distortion. Is this correct?
If so, then taming the 12s waveguide a little might actually result in a better overall sound? If so, then I would be interested in experimenting with that.
If so, then taming the 12s waveguide a little might actually result in a better overall sound? If so, then I would be interested in experimenting with that.
Phil,
waveguide lowers the distortion in comparison to tweeter on the flat baffle,
so you can cross it at a lower frequency. L pad serves a purpose to reduce the
spl of the tweeter anyway you want it. High fidelity assumes the level of both
of the drivers to be about the same.
Theoretically, you could improve the sound quality to the maximum if you
wanted it, with the right tools and idea how to.
waveguide lowers the distortion in comparison to tweeter on the flat baffle,
so you can cross it at a lower frequency. L pad serves a purpose to reduce the
spl of the tweeter anyway you want it. High fidelity assumes the level of both
of the drivers to be about the same.
Theoretically, you could improve the sound quality to the maximum if you
wanted it, with the right tools and idea how to.
Phil,
I'd be hooking up an L pad fast and see if you can tune them to your liking.
You may have a Radio Shack up there, they have them.
I'd be hooking up an L pad fast and see if you can tune them to your liking.
You may have a Radio Shack up there, they have them.
I don't think there's a Radio Shack in Canada these days, and "The Source" has very few DIYer parts available
but these folks, perhaps Q-Components loudspeakers & audio products
might be able to help with replacement drivers as well - i.e. Goldwood, Eminence, etc ?
but these folks, perhaps Q-Components loudspeakers & audio products
might be able to help with replacement drivers as well - i.e. Goldwood, Eminence, etc ?
With the sound focussed in a more narrow beam it will be louder on axis for a similar tweeter effort, so you could take advantage to push it harder.
The waveguide is quite small, and probably too small to be much help at the frequency where the 12 is doing the same directivity. You could try making it larger. As an example, if you had a pool noodle (the long narrow cylindrical floating device, it's simple but other things may work better.) and slice an edge off down its length, attaching it around the waveguide. The roundover helps.
For what it's worth, here are the measured specs for a pair of 12S that I just took in. 12" woofer runs full range and likely rolls off naturally at the crossover point.
Piston dia = 10.375"
SPL = 91.64 (calculated)
Re = 3.809
Fs = 35.66
Qts = 0.5446
Qes = 0.6355
Qms = 3.809
Le = 0.4244
Mms = 63.08
Vas = 4.667 cu ft
Piston dia = 10.375"
SPL = 91.64 (calculated)
Re = 3.809
Fs = 35.66
Qts = 0.5446
Qes = 0.6355
Qms = 3.809
Le = 0.4244
Mms = 63.08
Vas = 4.667 cu ft
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