AE Lambda Midbass 10 Project?

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Re: Re: Re: Re: Tang Band W8-1722

LineSource said:



http://attlid.eu/spam/W8-1722.jpg


This 2.3MB jpg includes T/S specs, SPL vs. freq, and distortion plots.
The DCR impedance is 3.6R. Not too good for those who plan to use two of them. 88db sensitivity is low for an 8".
The Jantzen Ja8008 by Seas has better sensitivity at 94/95db. Paper cone with foam surrounds. No mention about faraday ring. Can't find the price for them.
 
Re: Re: Re: Re: Re: Tang Band W8-1722

SamL said:

The Jantzen Ja8008 by Seas has better sensitivity at 94/95db. Paper cone with foam surrounds. No mention about faraday ring. Can't find the price for them.

This driver calculates out to 93.05dB 1W. I don't expect any shorting ring is being used, or if it is, it is clearly not effective based on the impedance curve. Also pay attention to the resonance centered about 900hz. It appears as a clear peak in the impedance curve and a dip in the response curve at the same point. Also the PDF file states "Be aware that normal box-simulations do not apply to this kind of driver." I'm curious as to why that would be? :confused:

We shouldn't be too far out on the 10" midrange driver. I have lighter samples of the 10" and 12" cones coming with a new material that Nick believes will be be best for the midrange. I will also be working on the 6.5" and 8" drivers soon as well. We really need a good, 95db+ 6.5" driver for 3way systems, and nothing I have tested is really up to par. If the cone samples prove acceptable I'll be on to those soon as well.

John
 
Re: Re: Re: Re: Re: Re: Tang Band W8-1722

John_E_Janowitz said:
We shouldn't be too far out on the 10" midrange driver. I have lighter samples of the 10" and 12" cones coming with a new material that Nick believes will be be best for the midrange. John


John - Nick....Please consider prototyping a 10" underhung motor midrange with a 0.85" thick AlNiCo ring magnet in place of the current ceramic. It sounds like your magnet charger equipment is adequate to handle AlNiCo. The increase in gap flux will acheive the required BL at lower Mms and higher Xmax from a shorter-lighter copper voice coil, and AlNiCo has better resistance to reverse EMF flux drop. Can you prototpye a thicker rear pole steel which seems to saturate first?

SamL...a solid state diy'er could build a 25W super-sym Class-A amp that could easily drive a 1-2 ohm load of two W8-1722 in MTM parallel with 99 db/watt efficiency. This could mate to a 99db/watt diy ribbon tweeter with 2-ohm transformer. Small wattage Class-A bipolar amps sound sweet to my ears.
 
Re: Re: Re: Re: Re: Re: Tang Band W8-1722

John_E_Janowitz said:
We shouldn't be too far out on the 10" midrange driver. I have lighter samples of the 10" and 12" cones coming with a new material that Nick believes will be be best for the midrange. I will also be working on the 6.5" and 8" drivers soon as well. We really need a good, 95db+ 6.5" driver for 3way systems, and nothing I have tested is really up to par. If the cone samples prove acceptable I'll be on to those soon as well.

John
Damn. I haven't even got my 10M's yet and you're coming out with a higher efficiency version. I'm going to have to watch out for those as the 10M's will only be>250Hz in my system.
 
Re: Re: Re: Re: Re: Re: Tang Band W8-1722

John_E_Janowitz said:


I will also be working on the 6.5" and 8" drivers soon as well. We really need a good, 95db+ 6.5" driver for 3way systems, and nothing I have tested is really up to par. If the cone samples prove acceptable I'll be on to those soon as well.

John

A 6.5" will go very nicely with one of your TD12 in a 3 way. The 8" will be nice for OB mid ... you going to make us drool.
 
Re: Re: Re: Re: Re: Re: Re: Tang Band W8-1722

LineSource said:
John - Nick....Please consider prototyping a 10" underhung motor midrange with a 0.85" thick AlNiCo ring magnet in place of the current ceramic. It sounds like your magnet charger equipment is adequate to handle AlNiCo. The increase in gap flux will acheive the required BL at lower Mms and higher Xmax from a shorter-lighter copper voice coil, and AlNiCo has better resistance to reverse EMF flux drop. Can you prototpye a thicker rear pole steel which seems to saturate first?

SamL...a solid state diy'er could build a 25W super-sym Class-A amp that could easily drive a 1-2 ohm load of two W8-1722 in MTM parallel with 99 db/watt efficiency. This could mate to a 99db/watt diy ribbon tweeter with 2-ohm transformer. Small wattage Class-A bipolar amps sound sweet to my ears.


We will be doing Alnico options for all the TD drivers some day. It may be 6-12mos out though. As far as a .85" thick Alnico ring goes, that wouldn't be too practical. Alnico needs to have at least at 4:1 height to diameter ratio or it will short itself out. So if this was the case, you'd only be able to have about .21" thickness to the ring and not be very practical. We have 2 sizes we're working with. One is a 4.5" OD x 3" ID x 1.75" tall. The other is a 3" OD x 2.25" ID x 1.5" tall. These 2 sizes give us many options for both 2" and 2.5" coil drivers. Adding an additional disc of alico to the pole if/when needed gives us further ability to get the correct amount of flux in the gap.

Also, the Alnico won't give us different parameters or increase in flux compared to the ceramics. We can get any parameters or any amount of flux in the gap we want with either the Alnico or ceramic, or neo if we had a magnetizer to do that. The limit is simply the pole saturating before anything else. The only option from there is to go with a larger diameter pole to have more steel available.

Again, in your FEA from before, you are looking at only a 2d snapshot of the driver. You can't use it for BL comparisons between ceramic, neo, alnico. Without a 3d model you will get results like you are showing where the base of the back plate saturates first, but in reality it is the pole that is first to saturate. FEMM is good only to determine how linear your flux will be in the gap, but can't give you absolute flux comparisons for a 3d part.

John
 
Re: Re: Re: Re: Re: Re: Re: Tang Band W8-1722

SamL said:

A 6.5" will go very nicely with one of your TD12 in a 3 way. The 8" will be nice for OB mid ... you going to make us drool.


The 6.5" was the problem we ran into in doing a 3way as discussed here:

http://www.avsforum.com/avs-vb/showthread.php?t=1035126

We planned on a 6.5" to cover approximately 300hz to 3KHz, but just can't find any 6.5" that can cover the range and sound as good as the TD10M, 12M, or 15M. We simply have to make one as nothing available measures up. We will also be doing some waveguides in the future allowing for some very nice 2way systems. A TD12M mated to the 12" round waveguide for example or a TD15M mated too the 15" round waveguide would be an extremely simple solution.

John
 
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I understand the need fore a 6" hifi mid with say 93db sensitivity

But fore a higher sensitivity mid B&C 8PE21 could be the one to beat;)

http://www.bcspeakers.com/index.php?sez=1&categoria=1&id_descrizione=2&prodotto=3

A smaller neo magnet would be good at making a more open back
Also the B&C has short +/-1mm Xmax, double that would be better or maybe underhung even better
But I like that it rolls off by itself in the 250hz region...I have plans fore that:D
 
tinitus said:
I understand the need fore a 6" hifi mid with say 93db sensitivity

But fore a higher sensitivity mid B&C 8PE21 could be the one to beat;)

http://www.bcspeakers.com/index.php?sez=1&categoria=1&id_descrizione=2&prodotto=3

A smaller neo magnet would be good at making a more open back
Also the B&C has short +/-1mm Xmax, double that would be better or maybe underhung even better
But I like that it rolls off by itself in the 250hz region...I have plans fore that:D

We looked at the B&C's. In this case, there isn't really a benefit to the 8" B&C over our TD10M. You don't gain much in going from one size to the next in terms of off axis response. The inductance on the B&C is also double that of all the TD drivers and more than 4X what our midrange drivers will be.

If you look at the B&C 8PE21 impedance curve there is a big bump just below 1Khz and another at just under 3KHz. The one at 3KHz corresponds to the bump in the response curve. I'd also like to see what an unsmoothed response looks like. The copper cap helps a little, but not nearly as much as a full copper sleeve because inductance is still going to vary with excursion. The B&C may be better than most but still leaves a lot of room for improvement. :)

john
 
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Joined 2005
Yeah, but your TD10M is "only" 94db where B&C is 98db, which is different, but ok fore some designs, but not optimal fore use of CD tweeter...TD15M may be preferred then
Though TD10M may be super to use with ribbon

It has been claimed that TD15M is superiour to TD12M, does that count fore TD10M as well ?
 
tinitus said:
Yeah, but your TD10M is "only" 94db where B&C is 98db, which is different, but ok fore some designs

Graph shows 0.7 Q ported box for the T/S prameters I've prosted here for a Lambda 10" midbass, and the B&C 8PE21. The B&C is spec'ed at 1mm Xmax and Qtx 0.21 which seems best suited for a horn. The Lambda goal is 8mm Xmax, and a Qtc ~ 0.5, which is also a good match for a dipole design.
 

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tinitus said:
Yeah, but your TD10M is "only" 94db where B&C is 98db, which is different, but ok fore some designs, but not optimal fore use of CD tweeter...TD15M may be preferred then
Though TD10M may be super to use with ribbon

It has been claimed that TD15M is superiour to TD12M, does that count fore TD10M as well ?


Yeah, the TD10M won't be the eventual version though. Both the 10" and 12" were a little low in sensitivity as the cones were needlessly heavier than planned. The 10" cone was I believe 15grams and we have 10gram samples coming. The 12" was 20 grams and we have 12gram cone samples coming. Also these drivers have 6mm Xmax approximately. I could easily shorten the coil lowering mass more and putting more turns in the gap. A 1-2mm Xmax driver could easily be in the 98dB range.

John
 
I don't see why one can't use a 94dB woofer with a CD.
CD's almost always have more sensitivity than the LF.

I'd much rather have 6mm xmax then 3dB more sensitivity as, well, power isn't that expensive.

I think, and I could be wrong, but this is kind of a woofer for a two way system. I think that's a great idea, and I don't see 94dB sensitivity as being an issue. There are doubtfully any tweeters that can keep up besides horns.

Am I missing something?


Portland Mike
 
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LineSource said:


Graph shows 0.7 Q ported box for the T/S prameters I've prosted here for a Lambda 10" midbass, and the B&C 8PE21. The B&C is spec'ed at 1mm Xmax and Qtx 0.21 which seems best suited for a horn. The Lambda goal is 8mm Xmax, and a Qtc ~ 0.5, which is also a good match for a dipole design.


You must have been fiddling a lot with that sim as I get F3 around 85hz with TD10M in BR
 
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John_E_Janowitz said:



Yeah, the TD10M won't be the eventual version though.

John


I will be waiting ... just tune fore best FR response and sound Q ... and btw, I would like to see an 18" too :)

btw... the B&C 8PE21 is kind of low cost at 110USD:D


Mike, we agree that 94db may be ok, I just wont be wasting my time and be troubled with a CD waveguide and only get 94db ... and probably even less, unless its a 3way with a big woofer and highish xo point ... remember BSC ... man, why do we make speaker design so difficult ;)
 
tinitus said:



I will be waiting ... just tune fore best FR response and sound Q ... and btw, I would like to see an 18" too :)

btw... the B&C 8PE21 is kind of low cost at 110USD:D


Mike, we agree that 94db may be ok, I just wont be wasting my time and be troubled with a CD waveguide and only get 94db ... and probably even less, unless its a 3way with a big woofer and highish xo point ... remember BSC ... man, why do we make speaker design so difficult ;)


Hi Tinitus,

I'd just hit it with 100W and call it a day. That will fill my living room just fine I'd bet.
I've been looking for a good woofer (and I use that word lightly around you guys;>) that could work in a ~3 cu ft "bookshelf" and what Nick is discribing would I think fit the bill.
Maybe I'll tap you for a waveguide design!
I'm going from 4 15" to a single wimpy xmax 10" and find it works very well, but 1mm xmax doesn't cut it as a woofer even though it can play low enough... almost.

Regards,

Mike
 
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