Possible midranges for a 3-way speaker

[lsiberian]

I had a bit of an exchange with Mark in another forum and as a result have begun researching amplifiers and potential drivers for a 3 way design.

The combination of Mark's ideas and the inspiration of the omni-polar capabilities of the HiFi RTI tweeter without the faceplate have caused me to rethink my next speaker build. As an engineer I'm used to throwing around lots of ideas and eventually landing on something I execute when appropriate funds, time and motivation combine.

I've come up with 3 possible drivers from the full-range type driver category through evaluation of their measured responses from Zaph audio combined with their value. I realize a 200 dollar driver might be just the thing for those with larger budgets. But if a 20 dollar driver meets the demands of the system adequately I see no point in spending the extra 180.

As a result of my research these are 3 potential drivers I may evaluate.

Fountek FR88-EX(25)
HiVi B3S(12)
Tang Band W5-704D(25)

I like Tang Band for its higher wattage rating.
The HiVi has the lowest price and a great review from Zaph
The Fountek has a great review as well and looks very promising.

You can see this is a budget oriented design with the RT1 tweeter and a Dayton RS woofer to be selected. Let's just say I hope I'm onto something rather than on something.

 

[jinjuku]

I had a bit of an exchange with Mark in another forum and as a result have begun researching amplifiers and potential drivers for a 3 way design.

The combination of Mark's ideas and the inspiration of the omni-polar capabilities of the HiFi RTI tweeter without the faceplate have caused me to rethink my next speaker build. As an engineer I'm used to throwing around lots of ideas and eventually landing on something I execute when appropriate funds, time and motivation combine.

I've come up with 3 possible drivers from the full-range type driver category through evaluation of their measured responses from Zaph audio combined with their value. I realize a 200 dollar driver might be just the thing for those with larger budgets. But if a 20 dollar driver meets the demands of the system adequately I see no point in spending the extra 180.

As a result of my research these are 3 potential drivers I may evaluate.

Fountek FR88-EX(25)
HiVi B3S(12)
Tang Band W5-704D(25)

I like Tang Band for its higher wattage rating.
The HiVi has the lowest price and a great review from Zaph
The Fountek has a great review as well and looks very promising.

You can see this is a budget oriented design with the RT1 tweeter and a Dayton RS woofer to be selected. Let's just say I hope I'm onto something rather than on something.

Glad to see a true blue 3 way design. I don't know about any one else but I am tired of a lot of these designs using 4.5" and 5.25" multiple driver arrays. Get in there with a 7.5 or 8 inch driver, mid, and tweeter.

I miss the punch that those drivers provide (even with sub) because the sub isn't authoritative when it comes to stuff hitting hard in the 100-900/1000khz range.

Everyone wants a slim tower, they seem to want to avoid the monkey coffin. But it's went too far. Give me a good rock and roll speaker

 

[jeffsg4mac]

Everyone wants a slim tower, they seem to want to avoid the monkey coffin. But it's went too far. Give me a good rock and roll speaker

Here you go, get a pair of these baby's for your rock and roll

http://www.audioworld.com/stat/pr/0305/28.altec.lansing.legacy.a7.loudspeaker.shtml

 

[TLS Guy]

I had a bit of an exchange with Mark in another forum and as a result have begun researching amplifiers and potential drivers for a 3 way design.

The combination of Mark's ideas and the inspiration of the omni-polar capabilities of the HiFi RTI tweeter without the faceplate have caused me to rethink my next speaker build. As an engineer I'm used to throwing around lots of ideas and eventually landing on something I execute when appropriate funds, time and motivation combine.

I've come up with 3 possible drivers from the full-range type driver category through evaluation of their measured responses from Zaph audio combined with their value. I realize a 200 dollar driver might be just the thing for those with larger budgets. But if a 20 dollar driver meets the demands of the system adequately I see no point in spending the extra 180.

As a result of my research these are 3 potential drivers I may evaluate.

Fountek FR88-EX(25)
HiVi B3S(12)
Tang Band W5-704D(25)

I like Tang Band for its higher wattage rating.
The HiVi has the lowest price and a great review from Zaph
The Fountek has a great review as well and looks very promising.

You can see this is a budget oriented design with the RT1 tweeter and a Dayton RS woofer to be selected. Let's just say I hope I'm onto something rather than on something.

There is a lot of power in the mid range. I don't consider the Fountek ot HiVi units as having enough power, except for high definition low power system. The Tang Band is more promising. You would need two in MTM. The roll off is nice.

I know you are considering an active speaker. The Tang Band would be nice as you could use two amps with crossover around 350 Hz and all you would need for the tweeter would be one cap, first order. You could let the mids roll off acoustically. That would give you a speaker with around 120 watts with a sensitivity of 94 db 2.83 volts I meter on the top end. That would give plenty of acoustic output under domestic conditions.

The lack of a really good wide band mid with good power handling is a definite problem. I may well go to my parts and pick up where I left off 35 years ago, and develop my own mid driver.

We really need something as good and powerful as the mid range of the B & W 800 series. If you are going active the ATC SM-150 would be a good choice except for cost. It is considered by many to be the finest mid range available.

 

[WmAx]

The Infinity MRS driver has very high output ability, MASSIVE thermal capacity, and an effective bandwidth of 160Hz-5000Hz(top end based on dispersion characteristics). You can cross as low as 110Hz, but dynamic range will be restricted to more typical levels. The driver needs 300 watts or more IMO, to get benefit of it's abilities. 300 watts will not over drive this mid; a 350 watt amplifier clipped before I could exceed this driver's limits. However, this is not a cheap driver. About $100 each plus shipping from Harman parts department.

Another possibility is the Dayton RS52 dome mid. It is low in cost and high in performance, and can be crossed high with excellent dispersion characteristics. It needs to be crossed at 450 Hz with a steep crossover.

BTW, you can also buy the B&W drivers from B&W for reasonable costs. They have a 5" version of the high end FST mid used on their 800 series available for about $100-$120 each. This would be suitable to cross to the tweeter also, as the special B&W mid has ability to cross higher than a traditional driver of the same diameter, as it operates at least partially as a bending mode driver by intentional design.

-Chris

 

[lsiberian]

Chris is the MRS driver the woofer listed under the Cascade 3?

I'm intrigued by it's design.

 

[TLS Guy]

The Infinity MRS driver has very high output ability, MASSIVE thermal capacity, and an effective bandwidth of 160Hz-5000Hz(top end based on dispersion characteristics). You can cross as low as 110Hz, but dynamic range will be restricted to more typical levels. The driver needs 300 watts or more IMO, to get benefit of it's abilities. 300 watts will not over drive this mid; a 350 watt amplifier clipped before I could exceed this driver's limits. However, this is not a cheap driver. About $100 each plus shipping from Harman parts department.

Another possibility is the Dayton RS52 dome mid. It is low in cost and high in performance, and can be crossed high with excellent dispersion characteristics. It needs to be crossed at 450 Hz with a steep crossover.

BTW, you can also buy the B&W drivers from B&W for reasonable costs. They have a 5" version of the high end FST mid used on their 800 series available for about $100-$120 each. This would be suitable to cross to the tweeter also, as the special B&W mid has ability to cross higher than a traditional driver of the same diameter, as it operates at least partially as a bending mode driver by intentional design.

-Chris

Chris, do you have a link for the infinity driver you mentioned? I have tried to find it before, but can't find mention of it anywhere.

I was not aware that B & W supplied drivers outside of direct replacement for registered products. What information do you have contrary to that? I would just love to get my hands on a pair of those B & W mids.

 

[lsiberian]

http://www.harmanaudio.com/search_browse/partlist.asp?Parts=CASCADE3CBK&BrandId=INF&MarketId=HOM

The woofer He's talking about.

This is the whitepaper on the technology

http://www.infinityloudspeakers.com.au/docs/mrs_whitepaper.pdf

 

[WmAx]

Chris, do you have a link for the infinity driver you mentioned? I have tried to find it before, but can't find mention of it anywhere.

I was not aware that B & W supplied drivers outside of direct replacement for registered products. What information do you have contrary to that? I would just love to get my hands on a pair of those B & W mids.

I contacted B&W Tech Support about a year ago and they gave me prices for drivers and are perfectly willing to sell any parts. Prices are actually very reasonable; what you would expect to pay for the comparable product on the DIY market. The FST mid is available in 6-7" (as on the high end 800 series) and in 5" (it is used on one of the CM range towers). B&W claims the 5" version is the very same mid/technology, just smaller diameter (for where the smaller diameter is physically needed). I was considering using the FST midrange on my computer speakers. I ended up using an Infinity MMD mid-bass driver instead.

-Chris

 

[TLS Guy]

I contacted B&W Tech Support about a year ago and they gave me prices for drivers and are perfectly willing to sell any parts. Prices are actually very reasonable; what you would expect to pay for the comparable product on the DIY market. The FST mid is available in 6-7" (as on the high end 800 series) and in 5" (it is used on one of the CM range towers). B&W claims the 5" version is the very same mid/technology, just smaller diameter (for where the smaller diameter is physically needed). I was considering using the FST midrange on my computer speakers. I ended up using an Infinity MMD mid-bass driver instead.

-Chris

I have Emailed B & W tech support. I will see what sort of response I get.

I note that Infinity cross that MRS driver over at 1500 Hz. I would have thought that a flat panel speaker like that would really start to beam as frequency increased. I doubt that driver would suit my purpose.

The pickings are pretty slim for a wide band mid range driver.

 

[WmAx]

I have Emailed B & W tech support. I will see what sort of response I get.

I note that Infinity cross that MRS driver over at 1500 Hz. I would have thought that a flat panel speaker like that would really start to beam as frequency increased. I doubt that driver would suit my purpose.

The pickings are pretty slim for a wide band mid range driver.

I'm not sure if you will even get a useful response through e-mail. I failed. But I was able to get the information I needed through an actual phone call.

The Infinity MRS driver has near perfect off axis response (4000-5000Hz range, 75 degrees +/- horizontal). It's first break up mode is around 12500 Hz. I have no idea why Infinity uses so little of the driver's potential bandwidth.

http://www.linaeum.com/productinfo/other/infinity_cascade_driver/fr_offaxis.gif

I have analyzed the driver thoroughly. Crossed at 4.8Khz, both horiztonal and vertical response have a sufficiently wide window. My off axis requirements are FAR beyond the normal requirements. Realize, I require a front and back plane set of drivers to be able to operate together and load a room like an omnipolar across the ENTIRE AUDIBLE BANDWIDTH.

Prototype baffle/cabinet(3' wide, 6" side radius on corners) with MRS + naked HI-VI RTI element: http://www.linaeum.com/productinfo/other/infinity_cascade_driver/comboexample1.gif

Off axis response speaks for itself. Vertical response is also excellent, overall. The lobing is not significant for what corresponds to almost +/- 2 feet vertical window at a 8-9 foot seating distance. Note: this is an exploration response set. Almost no response optimization has been applied to target the flattest possible response. Other than the crossover area itself, this response chart has no EQ correction(s) applied to the rest of the response. As this is a fully active system, full optimization will be in effect for the actual final system response.

-Chris

 

[TLS Guy]

Many thanks for the above data. It the infinity driver does look promising. I'm astonished that the driver has such a good polar response. It seems to me the membrane most not be uniformly driven, otherwise the axis plots could not look like that.

This is the reply I get from B & W which puts those drivers out of court: -

Hello and thank you for your email. I will need to know what model you
want the midrange for? We only sell spare parts to customers who own our
speakers. You must provide a serial number and proof of purchase.

Best Regards
Eric John McBride
Bowers and Wilkins
Service Manager
CT-800

 

[lsiberian]

I'm not sure if you will even get a useful response through e-mail. I failed. But I was able to get the information I needed through an actual phone call.

The Infinity MRS driver has near perfect off axis response (4000-5000Hz range, 75 degrees +/- horizontal). It's first break up mode is around 12500 Hz. I have no idea why Infinity uses so little of the driver's potential bandwidth.

http://www.linaeum.com/productinfo/other/infinity_cascade_driver/fr_offaxis.gif

I have analyzed the driver thoroughly. Crossed at 4.8Khz, both horiztonal and vertical response have a sufficiently wide window. My off axis requirements are FAR beyond the normal requirements. Realize, I require a front and back plane set of drivers to be able to operate together and load a room like an omnipolar across the ENTIRE AUDIBLE BANDWIDTH.

Prototype baffle/cabinet(3' wide, 6" side radius on corners) with MRS + naked HI-VI RTI element: http://www.linaeum.com/productinfo/other/infinity_cascade_driver/comboexample1.gif

Off axis response speaks for itself. Vertical response is also excellent, overall. The lobing is not significant for what corresponds to almost +/- 2 feet vertical window at a 8-9 foot seating distance. Note: this is an exploration response set. Almost no response optimization has been applied to target the flattest possible response. Other than the crossover area itself, this response chart has no EQ correction(s) applied to the rest of the response. As this is a fully active system, full optimization will be in effect for the actual final system response.

-Chris

Chris that looks absolutely incredible for a 100 dollar driver. I hope these drivers are still available via the parts store when I'm ready for my next build.

I've always been a fan of infinity drivers. Sadly they put their speakers in substandard enclosures.

 

[WmAx]

Many thanks for the above data. It the infinity driver does look promising. I'm astonished that the driver has such a good polar response. It seems to me the membrane most not be uniformly driven, otherwise the axis plots could not look like that.

This is the reply I get from B & W which puts those drivers out of court: -

Hello and thank you for your email. I will need to know what model you
want the midrange for? We only sell spare parts to customers who own our
speakers. You must provide a serial number and proof of purchase.

Best Regards
Eric John McBride
Bowers and Wilkins
Service Manager
CT-800

Perhaps they have changed policy. A year ago, they had no such requirement for me. In any event, even that would not stop me. It's easy enough to track down an owner and get some valid serials if you really want the drivers.

Interesting Fact: A few years ago, one of the top sound quality car audio winners actually used the 800 series mids, tweeters and crossovers and built massive pods in the A pillar/dash area of his car to house them. He won many shows non stop until he retired the system.

As for the Infinity driver, it's acts as a piston. It's ultra rigid in every axis. But in reality, the horizontal radiation area is only 2.75" and the vertical is something like 6.5". Vertical of course does not have to be nearly as good. Also, it seems that a cone introduces additional problems with off axis response in it's top band that a flat driver completely lacks.

-Chris

 

[TLS Guy]

Perhaps they have changed policy. A year ago, they had no such requirement for me. In any event, even that would not stop me. It's easy enough to track down an owner and get some valid serials if you really want the drivers.

Interesting Fact: A few years ago, one of the top sound quality car audio winners actually used the 800 series mids, tweeters and crossovers and built massive pods in the A pillar/dash area of his car to house them. He won many shows non stop until he retired the system.

As for the Infinity driver, it's acts as a piston. It's ultra rigid in every axis. But in reality, the horizontal radiation area is only 2.75" and the vertical is something like 6.5". Vertical of course does not have to be nearly as good. Also, it seems that a cone introduces additional problems with off axis response in it's top band that a flat driver completely lacks.

-Chris

That would explain the plots. A wavelength of 2.75" Has a frequency of 4.8 kHz, so that is just were the the driver starts to beam. It seems to me that this driver is much more akin to a ribbon, and likely best crossoved to a ribbon at 4 K Hz. However that fulfills the criteria of having a driver be crossed in around 350 Hz and handed over at 4 kHz, which gets the crossover out of the speech discrimination band.

The next problem is aesthetic, as the HF ribbon would have to be on top of the mid, which would make for a tall center. You obviously would not want to use those drivers rotated 90 degrees, although I see Infinity do, but that can't be anything like optimal.

 

[WmAx]

That would explain the plots. A wavelength of 2.75" Has a frequency of 4.8 kHz, so that is just were the the driver starts to beam. It seems to me that this driver is much more akin to a ribbon, and likely best crossoved to a ribbon at 4 K Hz. However that fulfills the criteria of having a driver be crossed in around 350 Hz and handed over at 4 kHz, which gets the crossover out of the speech discrimination band.

The next problem is aesthetic, as the HF ribbon would have to be on top of the mid, which would make for a tall center. You obviously would not want to use those drivers rotated 90 degrees, although I see Infinity do, but that can't be anything like optimal.

Yes, aesthetics..... but I focus on performance 1st. For my particular design at this point, this is the best driver, and I have analyzed many units. I had a budget of several hundred dedicated to driver research.

Crossed at 200Hz and above, this driver can take several hundred watts with little thermal compression. A 350 watts amp clipped before being able to over drive this driver. It has incredible dynamic capabilities in an active system with appropriate power supplied. No doubt a result of the massive voice coil surface area (several times that of a regular driver). While not highly sensitive, the driver still has sensitivity in the 85db/1M/2.86V range, which is about average, but the huge thermal ability provides for something out of the ordinary. You can cross it as low as 160Hz and still have massive output ability. But under this and excursion limits are an issue. Infinity crosses it too low, thus giving up it's otherwise radical advantage. Their own claims are false in regards to massive power handling in so far as their designs are concerned - due to crossing the driver at such a low frequency.

But this is hardly the 1st time Infinity has developed an extraordinary driver and used it in suboptimal designs. The quality/performance provided by the mids and mid-bass drivers in their Primus speakers are phenomenal. Yet, most of that performance is lost due to average xovers and poor cabinet systems.

-Chris

 

[lsiberian]

It seems to me that this driver is much more akin to a ribbon, and likely best crossoved to a ribbon at 4 K Hz. However that fulfills the criteria of having a driver be crossed in around 350 Hz and handed over at 4 kHz, which gets the crossover out of the speech discrimination band.

My concern on trying to cross it with the RTI tweeter is there is a bit of a gap between the two, but this certainly is what the doctor ordered for a 3-way design. I think I will pencil this in for now.

I think finding a good low-cost low end driver would be next. I know the JL Audio 8w7-3 would probably be a dream bottom for such a speaker(I'm sure this is what Chris is using). But costs are pretty high(nearly 300 each) and would eliminate budget folks. Heck even this driver might eliminate some. I may give the JL Audio 8w6v1 I have a try. I'd prefer to build it in a separate enclosure. I've got a planned sealed enclosure for these already. But I would like to evaluate some of the RS woofers due to their low cost.

 

[WmAx]

My concern on trying to cross it with the RTI tweeter is there is a bit of a gap between the two, but this certainly is what the doctor ordered for a 3-way design. I think I will pencil this in for now.

I think finding a good low-cost low end driver would be next. I know the JL Audio 8w7-3 would probably be a dream bottom for such a speaker(I'm sure this is what Chris is using). But costs are pretty high(nearly 300 each) and would eliminate budget folks. Heck even this driver might eliminate some. I may give the JL Audio 8w6v1 I have a try. I'd prefer to build it in a separate enclosure. I've got a planned sealed enclosure for these already. But I would like to evaluate some of the RS woofers due to their low cost.

In early 2010, the 8" TC Sounds driver will be available ($200) from Sound Splinter. This is at least as good as the JL W7 8". There is also the Dayton Reference 8" sub. It is great mid-bass driver. Use it in a sealed section down to 55 - 60 Hz and hand over to stereo subs. Perfect. However, the TC sounds and W7 8" sealed can be used down to 35Hz with substantial clean output(30Hz with some mild limitations), which means you don't even 'need' a sub for music applications. Use ported cabinets and clean high output to 20-25 Hz is easily achieved, actually comparable in output to conventional designed high quality 12" drivers such as the Kappa Perfect 12 or Dayton Reference 12.

As for the MRS and crossing high (4-5kHz); as long as you mount the tweeter as close as physically possible, integration will turn out great at extreme off axis points. Refer to my prototype measurements I posted earlier. Show me a commercial speaker with that kind of off axis curves. You need to make a raised mount point so the thin tweeter mounts flush with the top edge of the MRS driver, for ideal results. You also need very large edge radius on the cabinets if you want smooth far off axis response from that super wide dispersion tweeter. I recommend no less than 2" radius. I am using 3" radius on the cabinets being built. My prototype cabinet used 6" radius. And do not skimp on power to either the MRS driver or 8" TC or JL W7 drivers. I recommend at least 300 (at 8 Ohms) to the MRS mid and 450 - 600 watts (4 Ohms) to the TC Sounds or W7 8" drivers.

Considering the very high amount of design and labor required, it would be silly to not use the best drivers possible for the application.

-Chris

 

[lsiberian]

In early 2010, the 8" TC Sounds driver will be available ($200) from Sound Splinter. This is at least as good as the JL W7 8".

-Chris

It looks like the 8w6 actually has a better upper range than the 8w7. An 8" TC Sounds driver sounds like a monster. I can't imagine the heads that could turn.

 

[WmAx]

It looks like the 8w6 actually has a better upper range than the 8w7. An 8" TC Sounds driver sounds like a monster. I can't imagine the heads that could turn.

I would not bother with the 8w6v2 in this application.

But I don't know what you mean about the response. The 8W7 has a flat response up to 800Hz or a little higher. But it should not be used beyond 160Hz with a steep crossover, because around 200Hz, distortion starts to rapidly increase to audible levels. This is due to the specific motor designed used in the W7. The TC Sound unit can probably be used up to 500Hz or higher, as it uses the TC2+ motor, which has copper shorting rings that should effect better upper frequency distortion characteristics. However, being that it has been on back order so long(due to TC Sound's bankruptcy), I have never had an opportunity to test one myself.

JL W7 8"

TC Sounds / Sound Splinter RE-badge 8"

-Chris