Possible midranges for a 3-way speaker

[lsiberian]

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

Might it be better to use a standard woofer to bottom the TRS then. I think we were talking about trying to get a 250 to 350hz crossover.

I have the version 1 8w6.

 

[WmAx]

Might it be better to use a standard woofer to bottom the TRS then. I think we were talking about trying to get a 250 to 350hz crossover.

I have the version 1 8w6.

If you want a 350Hz crossover point, then yes, you need a different woofer than the W7. But you need to remember that most energy in music is present in the 100Hz-500Hz band. Above 500Hz, baffle step re-enforces the output significantly, so you have substantially less actual power needed above this point. Another large shift in power required is above 3-4kHz or so; where energy is gradually decreasing.

The MRS driver is perfectly (if you use that) comfortable being used to 160-200Hz range with a 4th order electrical slop on high pass.

The 8w6v1 would need to be measured for cone break up points and distortion before I could recommend the product.

-Chris

 

[lsiberian]

If you want a 350Hz crossover point, then yes, you need a different woofer than the W7. But you need to remember that most energy in music is present in the 100Hz-500Hz band. Above 500Hz, baffle step re-enforces the output significantly, so you have substantially less actual power needed above this point. Another large shift in power required is above 3-4kHz or so; where energy is gradually decreasing.

The MRS driver is perfectly (if you use that) comfortable being used to 160-200Hz range with a 4th order electrical slop on high pass.

The 8w6v1 would need to be measured for cone break up points and distortion before I could recommend the product.

-Chris

Thanks for the recommendations. I'm definitely sold on the MRS driver. I think my next speaker budget purchase will sway that direction.

 

[tcarcio]

Kevin over at Exodus just introduced this speaker. Thought you guy's might like a look....http://www.hometheatershack.com/forums/exodus-audio/21503-introducing-anarchy.html?highlight=anarchy+woofer

 

[WmAx]

Two of those 6.5" would be suitable to take place of the 8" W7 or TC 8" for the lower midbass response (70Hz-160Hz) to match to the MRS midrange, although, the 8" TC or W7 would still likely produce more clean mid-bass output. But if the price is $40 each, then $80 per channel is cheaper than $200 per channel, for cheapskates like lisberian......

-Chris

 

[TLS Guy]

Kevin over at Exodus just introduced this speaker. Thought you guy's might like a look....http://www.hometheatershack.com/forums/exodus-audio/21503-introducing-anarchy.html?highlight=anarchy+woofer

A break up mode at 4.2 kHz is totally unsatisfactory. That is the problem with almost all of them, and that is one of the big problems.

 

[lsiberian]

Two of those 6.5" would be suitable to take place of the 8" W7 or TC 8" for the lower midbass response (70Hz-160Hz) to match to the MRS midrange, although, the 8" TC or W7 would still likely produce more clean mid-bass output. But if the price is $40 each, then $80 per channel is cheaper than $200 per channel, for cheapskates like lisberian......

-Chris

I suppose i could cheapen it further with Primus drivers for the midrange.

They run around 36 each from harman parts.

 

[WmAx]

A break up mode at 4.2 kHz is totally unsatisfactory. That is the problem with almost all of them, and that is one of the big problems.

Well, I thought he meant using it as the midbass in a 4 way, not using it as a midrange (which it would be poor unless crossed at 1.5kHz or lower).

-Chris

 

[WmAx]

I suppose i could cheapen it further with Primus drivers for the midrange.

They run around 36 each from harman parts.

The Primus mid does not have satisfactory dispersion up top to 'optimally' cross to the Hi Vi element. You can do it, and it will work, just not quite as perfect as the MRS. Also, you need to cross the Primus mid at 400Hz, where as the MRS can be crossed much lower.

-Chris

 

[lsiberian]

Well, I thought he meant using it as the midbass in a 4 way, not using it as a midrange (which it would be poor unless crossed at 1.5kHz or lower).

-Chris

Yeah that's the entire purpose of the design from what I can tell. It appears 1 modeled at a max of 118db before it hit excursion. Of course it will likely need to be held back from that, but still that's very impressive for a driver that cheap.

I'll use the drivers I have until I can afford a real upgrade though. It's probably a step sideways from the JL Audio 8 driver I have anyway. I plan to build the bottom as a separate module. To make it easier to move when the time comes.

I think the best bottoms are in this order.
TC Sounds 8"
JL Audio 8w7-3
Other stuff for cheapskates.

So to some up the plan so far(The amp Portion from a discussion with Mark earlier.)

Tweeter- a HiVi RTI driver
Midrange- an Infinity MRS driver
Woofer - use my JL Audio 8w6v1 until the TC Sounds 8" is available

The planned crossover is the next to discuss

Midrange to woofer = 160hz

Tweeter to midrange = 5-7k? Not sure what the HiVi can handle here Chris.

All Crossovers will be L-R 4 active(if Possible)

Class A amp for the tweeter.
Class AB for the midrange.
Class AB or D for the Woofer.

Next up would be enclosures and circuits for the amps or sources for the amps. I'm thinking for an amp design I'll need to access some EE resources or find some products that meet our need.

Thanks everyone for contributions. I want to contribute something useful to this forum and getting the knowledge out and into a useful DIY design would be terrific.

 

[WmAx]

Class A amp for the tweeter.
Class AB for the midrange.
Class AB or D for the Woofer.

Class A amps are nothing special. Just weak and ineffecient. Modern class AB has no crossover distortion of significance. I preer class AB output stages using tracking power supplies such as BASH or EEEngine Technology from Yamaha that gives the same efficiency as Class D amplifiers.

Next up would be enclosures and circuits for the amps or sources for the amps. I'm thinking for an amp design I'll need to access some EE resources or find some products that meet our need.

While you can make the amp for the tweeters, don't bother for the mid and woofers. It will cost you more than buying commercial units to get the power levels that are optimal for these drivers. Do not try to skimp on power. 300W minimum for the MRS and 450W minimum for the TC or W7 8" driver. 50 watts is sufficient for the tweeter, though I still use much more than that.

-Chris

 

[lsiberian]

Class A amps are nothing special. Just weak and ineffecient. Modern class AB has no crossover distortion of significance. I preer class AB output stages using tracking power supplies such as BASH or EEEngine Technology from Yamaha that gives the same efficiency as Class D amplifiers.




While you can make the amp for the tweeters, don't bother for the mid and woofers. It will cost you more than buying commercial units to get the power levels that are optimal for these drivers. Do not try to skimp on power. 300W minimum for the MRS and 450W minimum for the TC or W7 8" driver. 50 watts is sufficient for the tweeter, though I still use much more than that.

-Chris

Mark raised a concern with blowing the tweeter in high power situations. I would most certainly not buy a class A amp which is a very costly investment.

Have you ever heard of 41hz.com?

They use tripath amps and seem to be a good source for DIY amp construction. For a small tweeter amp it might be just the thing. For the bass and mid driver I'll be going with a pro level amp. Unless I just really find myself enjoying building amps in which case it would be for the fun more than the value. It probably sounds nuts. But that's what most people think of my speaker building hobby.

 

[TLS Guy]

If you want a 350Hz crossover point, then yes, you need a different woofer than the W7. But you need to remember that most energy in music is present in the 100Hz-500Hz band. Above 500Hz, baffle step re-enforces the output significantly, so you have substantially less actual power needed above this point. Another large shift in power required is above 3-4kHz or so; where energy is gradually decreasing.

The MRS driver is perfectly (if you use that) comfortable being used to 160-200Hz range with a 4th order electrical slop on high pass.

The 8w6v1 would need to be measured for cone break up points and distortion before I could recommend the product.

-Chris

Your point about declining energy as one moves up the frequency scale because of diffraction loss is well taken, however for classical music the power required in the mid range is frequently colossal. Massed strings and woodwind with a large brass chorus blazing over the top, produces a huge peak of energy in 500 to 2K range. An example the end of the Sibelius second symphony.

The biggest hog of mid range and HF is the 17th century pipe organ, and 20th and 21st century designs based on them. Everyone thinks of the organ as being demanding on the bass, and it is, but many instruments much more so above the bass stave.

Far too many three way designs are totally incapable in this regard.

I personally like a bass/mid pass band transition around 350 to 400 Hz to even stress on drivers and amps up.

So the power handling of that infinity driver really interest me.

I have been tossing around ideas for our Eagan home. This system will have to be neat and elegant. My biggest concern is how to make a satisfactory center speaker with that driver, that fulfills the neat and tidy requirement.

What are the outside dimensions of those units Chris?

 

[WmAx]

Mark raised a concern with blowing the tweeter in high power situations. I would most certainly not buy a class A amp which is a very costly investment.

Have you ever heard of 41hz.com?

They use tripath amps and seem to be a good source for DIY amp construction. For a small tweeter amp it might be just the thing. For the bass and mid driver I'll be going with a pro level amp. Unless I just really find myself enjoying building amps in which case it would be for the fun more than the value. It probably sounds nuts. But that's what most people think of my speaker building hobby.

The tweeter RT I element, crossed at 4.2kHz and higher, with a 4th order electrical filter slope, will not blow easily, even with huge SPL levels. The power in music is very reduced by this frequency. I have determined that, if you use a slow weighted SPL meter setting and measure your average music SPL across the entire audio band, that you will be in the 112-115dB range at 1 meter anechoic before damaging the tweeter. You must consider that the power range in music is primarily the mid-bass/mid-range, and the tweeter will actually be playing approximately 14-16dB less at any given time as compared to the mid-bass, if that tweeter is crossed at 4-5kHz. So while the mid-bass and mid-range are playing, they need in reality FAR more power than the tweeter crossed at 4-5kHz, assuming the tweeter has the same sensitivity level, which it does not; the tweeter is far more efficient and in addition is re-enforced by another 5-6db by the baffle step; thereby in reality, the tweeter actually only needs a tiny portion of the power of the mid-bass drivers discussed here for music signals, considering ALL real world factors. 50 Watts would be acceptable for this tweeter.

-Chris

 

[WmAx]

I personally like a bass/mid pass band transition around 350 to 400 Hz to even stress on drivers and amps up.

So the power handling of that infinity driver really interest me.

I have been tossing around ideas for our Eagan home. This system will have to be neat and elegant. My biggest concern is how to make a satisfactory center speaker with that driver, that fulfills the neat and tidy requirement.

What are the outside dimensions of those units Chris?

I should also note, just in case you care, and so that you are aware of all issues before deciding to use this driver, that the MRS driver I analyzed had very low distortion overall, except for a very narrow 1/5 octave space centered at about 700Hz where it is appreciable. This is inaudible on music completely, except under the most rare circumstance that a pure isolated sine wave was played within this 1/4th-1/5th octave span at moderate to high SPL(I don't have a single recording in my collection that meets this requirement to my knowledge). But everything is a compromise in speaker design as you well know, and I determined it acceptable considering the other radical advantages of this driver. Additionally, I suspect this is a unit specific issue that is not usually present. But I have not measured multiple units to determine this. While THD(total of ALL harmonics and noise) is around -45 to -46 dB (0.5%)most of the time, it rises to -30dB(3%) at the center of this 1/5th octave peak, using 90dB at 1 Meter test signals. There is also a very narrow distortion peak rise centered around 4.2 kHz. Not significant and not near the same level as the 700Hz anomaly.

Frame dimensions: 3 13/16" W x 8 1/4" H x 1" D. Diaphragm dimensions: 2.5" W x 6 15/16" H. Frame is made from thick cast metal alloy with black finish. Build quality is top notch, roughly comparable to SEAS Excel.

Due to the odd protruding tabs for screws and the raised frame on the front side, to get best cosmetic effect, one will have to make an overlay frame 1/4" thick to mount over and hide the screws/tabs and bring front frame edges flush to a surface/plane.

-Chris

 

[TLS Guy]

I should also note, just in case you care, and so that you are aware of all issues before deciding to use this driver, that the MRS driver I analyzed had very low distortion overall, except for a very narrow 1/5 octave space centered at about 700Hz where it is appreciable. This is inaudible on music completely, except under the most rare circumstance that a pure isolated sine wave was played within this 1/4th-1/5th octave span at moderate to high SPL(I don't have a single recording in my collection that meets this requirement to my knowledge). But everything is a compromise in speaker design as you well know, and I determined it acceptable considering the other radical advantages of this driver. Additionally, I suspect this is a unit specific issue that is not usually present. But I have not measured multiple units to determine this. While THD(total of ALL harmonics and noise) is around -45 to -46 dB (0.5%)most of the time, it rises to -30dB(3%) at the center of this 1/5th octave peak, using 90dB at 1 Meter test signals. There is also a very narrow distortion peak rise centered around 4.2 kHz. Not significant and not near the same level as the 700Hz anomaly.

Frame dimensions: 3 13/16" W x 8 1/4" H x 1" D. Diaphragm dimensions: 2.5" W x 6 15/16" H. Frame is made from thick cast metal alloy with black finish. Build quality is top notch, roughly comparable to SEAS Excel.

Due to the odd protruding tabs for screws and the raised frame on the front side, to get best cosmetic effect, one will have to make an overlay frame 1/4" thick to mount over and hide the screws/tabs and bring front frame edges flush to a surface/plane.

-Chris

Thanks Chris!

So it seems on could make a very narrow fronted speaker if one wished.

 

[lsiberian]

I'm ready to grab some midrange drivers

I've got some funds from a bonus so I may be looking to grab a midrange.

Right now I got an Infinity MRS on the list. I wonder what else might fill the bill.

 

[annunaki]

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

That is the same response I received last time I contacted them as well.

 

[annunaki]

A break up mode at 4.2 kHz is totally unsatisfactory. That is the problem with almost all of them, and that is one of the big problems.

Agreed. That is one of the reasons I have chosen to go active so I can easily notch filter as well a implement the best sounding x-over option with the click of the dial. 1st through 6th order options available at nearly any frequency.

I am currently doing a two way project for my living room surround system. All active.

 

[highfigh]

Mark raised a concern with blowing the tweeter in high power situations. I would most certainly not buy a class A amp which is a very costly investment.

Have you ever heard of 41hz.com?

They use tripath amps and seem to be a good source for DIY amp construction. For a small tweeter amp it might be just the thing. For the bass and mid driver I'll be going with a pro level amp. Unless I just really find myself enjoying building amps in which case it would be for the fun more than the value. It probably sounds nuts. But that's what most people think of my speaker building hobby.

Did you look at all of the kits at 41hz.com? Some look like they would work well for each band and with a 3-4 way crossover, you could mount the amplifier module on the speakers. Jamo had a model called MFB and it accepted preamp level input (DIN jacks), it was tri-amped and had motional feedback, which is why they were called MFB. They also had a 12 band graphic EQ on the front.

Do you have links for the actual drivers you're considering?