Glen,
Although I'm no expert here, my gut feeling is that by using two midrange drivers in this way you're reducing distortions that weren't necessarily in need of improvement, and introducing new distortions, higher cost and increased complexity.
If you want a midrange driver that can take massive hammer there's the Adire Extremis to name just one. With a suitable midrange there's simply no need to have more than one.
Simon
Although I'm no expert here, my gut feeling is that by using two midrange drivers in this way you're reducing distortions that weren't necessarily in need of improvement, and introducing new distortions, higher cost and increased complexity.
If you want a midrange driver that can take massive hammer there's the Adire Extremis to name just one. With a suitable midrange there's simply no need to have more than one.
Simon
Look at something very high end and you'll rarely see two mid drivers covering the same range:
http://www.bowers-wilkins.com/display.aspx?infid=1729
This one does have two mid drivers, but they're doing different things, and they use a single 4" cone to cover 220hz - 880hz.
Surely most 6" drivers are well on top of ~300hz+ with very low distortion.
Simon
ps - I heard Madonna has a set of Nautilus speakers
http://www.bowers-wilkins.com/display.aspx?infid=1729
This one does have two mid drivers, but they're doing different things, and they use a single 4" cone to cover 220hz - 880hz.
Surely most 6" drivers are well on top of ~300hz+ with very low distortion.
Simon
ps - I heard Madonna has a set of Nautilus speakers
AndrewT said:
All MTM's have lobing problems.
And I don't necessarily want to do what what everyone else is doing.
SimontY said:
I dunno. 1/4 the voice coil power and 1/2 the cone excursion with a series connected pair isn't something to pass on lighlty. Zaph on his mid-range driver test page makes comments WRT this advantage when MTMing in series.
The midrange driver is very important to the quality of the overall system and the LDC has a chart showing some pretty eye popping changes (for the worse) of driver paramaters with not much voice coil heating for an average driver.
Anyway, I just deleted one $400 woofer from the design, so I can absorb part of that with another mid-range driver
Cheers,
Glen
Please at least connect them in parallel. Series connections cause problems, and there's just no need for anything other than parallel considering your amp's current pushing ability.
I still can't understand why you'd connect two in a peculiar way when surely one larger one is easier, cheaper and quite likely better. The only "drawback" of a large midrange driver is beaming, but it'd have to be pretty large for it to be a real problem.
Simon
I still can't understand why you'd connect two in a peculiar way when surely one larger one is easier, cheaper and quite likely better. The only "drawback" of a large midrange driver is beaming, but it'd have to be pretty large for it to be a real problem.
Simon
Glen,
Nice towers, but I am with Simon , 1 midrange, the best you can buy.
Moreover, put the second wf in TMWW mode.
Voice coils aligned vertically (like B&W) is good.
Separates cabinets ( decoupling mechanical each of the others)
External Huge x-overs ( facilitating the modds)
just my personal preference.
Paolo
Nice towers, but I am with Simon , 1 midrange, the best you can buy.
Moreover, put the second wf in TMWW mode.
Voice coils aligned vertically (like B&W) is good.
Separates cabinets ( decoupling mechanical each of the others)
External Huge x-overs ( facilitating the modds)
just my personal preference.
Paolo
inertial said:Glen,
Nice towers, but I am with Simon , 1 midrange, the best you can buy.
Moreover, put the second wf in TMWW mode.
Voice coils aligned vertically (like B&W) is good.
Separates cabinets ( decoupling mechanical each of the others)
External Huge x-overs ( facilitating the modds)
just my personal preference.
Paolo
Now I want Glen to build a B&W Naultilus 803 clone
To rehash all of this into a single sentence again, why not do 3.5 way with BSC in the midrange? TMMWW or TMMWWW... or simply 3 way TMW (too ordinary?)
The benefits of the first suggestion (3.5 way) would be:
* only one, small, upper mid driver, therefore matching dispersion of the tweeter nicely
* secondary mid to perform BSC and reduce excursion in the lower midrange / upper bass
* multiple woofers crossed over low so their size, quantity or position is less critical
I don't see why you deleted the third woofer to be honest, nobody said it would cause real harm. Spreading those out will have some benefits as well as the drawbacks that B&W cited, and that of cost and size.
To be different, use sound, well-known principles and make the construction and crossover a masterpiece. The speaker will be unique and should be quite stunning after all's said and done. You can consider novel techniques for decoupling the top and mid drivers (magnet clamp holding the driver?), and as Paolo just suggested even decoupling the cabinets for top/mid and bass or even separate bits for all three (as long as you can keep the tweeter and midrange unit close).
Simon
The benefits of the first suggestion (3.5 way) would be:
* only one, small, upper mid driver, therefore matching dispersion of the tweeter nicely
* secondary mid to perform BSC and reduce excursion in the lower midrange / upper bass
* multiple woofers crossed over low so their size, quantity or position is less critical
I don't see why you deleted the third woofer to be honest, nobody said it would cause real harm. Spreading those out will have some benefits as well as the drawbacks that B&W cited, and that of cost and size.
To be different, use sound, well-known principles and make the construction and crossover a masterpiece. The speaker will be unique and should be quite stunning after all's said and done. You can consider novel techniques for decoupling the top and mid drivers (magnet clamp holding the driver?), and as Paolo just suggested even decoupling the cabinets for top/mid and bass or even separate bits for all three (as long as you can keep the tweeter and midrange unit close).
Simon
SimontY said:
Ermmm, I'm not connecting anything ATM, I'm just floating ideas and weighing up the pro's and con's.
I already told you the supposed benefits of connecting a pair of midrange drivers /small woofers in series (read in part from the Zaph site).
Connecting a pair in parallel would be completely pointless regardless of my amp current capability as the sensitivity isn't required to compete with the bass woofer pair. It would then just have to be padded out.
So series connection causes problems? What are they?
Cheers,
Glen
You've got me there
I only "know" this from what loads of people have told me, but I can't offer the technical explanation, it goes above my head. Anyone else?
Simon
ps. I use series-parallel connection in my current speakers but that's only because I had dozens of the drivers already and my amp can't drive the 1ohm load of an all-parallel connection. Also it's an open-baffle so it starts with an advantage in terms of low bass colouration.
I only "know" this from what loads of people have told me, but I can't offer the technical explanation, it goes above my head. Anyone else?
Simon
ps. I use series-parallel connection in my current speakers but that's only because I had dozens of the drivers already and my amp can't drive the 1ohm load of an all-parallel connection. Also it's an open-baffle so it starts with an advantage in terms of low bass colouration.
Hi Glen,
Lobing issues can be audible if you bob up and down to detect them, but whether they are an important issue when you are close to the tweeter axis is most debateable.
If the tweeter is between 'mids' having different characteristcs, say one upper mid the other lower mid or upper bass, I feel you will get more noticeable sound lobe than with D'Apollito.
Mid drivers in series are not subject to the same series connected errors as LF drivers. I would normally fit equal value damping resistors across the terminals of each series driver anyway.
Can I suggest you make a cardboard box mock up to try the alternatives your well stocked driver cupboard will permit before you make any decisions about cutting.
Cheers ...... Graham.
PS. Read up on Joe's Elsinore project, also here at diyAudio.
Lobing issues can be audible if you bob up and down to detect them, but whether they are an important issue when you are close to the tweeter axis is most debateable.
If the tweeter is between 'mids' having different characteristcs, say one upper mid the other lower mid or upper bass, I feel you will get more noticeable sound lobe than with D'Apollito.
Mid drivers in series are not subject to the same series connected errors as LF drivers. I would normally fit equal value damping resistors across the terminals of each series driver anyway.
Can I suggest you make a cardboard box mock up to try the alternatives your well stocked driver cupboard will permit before you make any decisions about cutting.
Cheers ...... Graham.
PS. Read up on Joe's Elsinore project, also here at diyAudio.
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