[ThomasW]

There are currently 3 variants of this design.

All versions use the BMS 4540ND 1" compression driver combined with the DDS ENG-1 waveguide. Mids are either the Accuton C95-T6 or Accuton C90-T6. Woofers are the builder's personal choice. Craig and I have an active crossover section between the MT and Woofer sections. MT section has passive crossovers. Jon's version has all passive crossovers. All the passive crossover sections utilized Steen Dueland's design concepts.

Below is Craig J's version, his baffle is Corian with hardwood trim. Woofers are the PE RSS315



This is designer Jon Marsh's version. He's using the 18" Ciare woofer and very $pendy Accuton. This version as the rare graphite figured MDF veneer ....



My prototypes have the C95-T6 mid with a PE RSS390



Pic of the MT section crossovers in my prototypes



I'm not sure of this forum's policy regarding links to other forums, so I won't post a link to the design/build thread. It's likely most readers are smart enough to find this info anyway...

Regards
ThomasW

[gitarretyp]

I'm glad to see you posting here regarding this design. I've posted links to the Isiris several times in other threads. I'd love to see some measurements of Craig's version and yours when finished (impedance, on and off axis frequency response, power response), if they're available. Also, how efficient are the designs using the dayton drivers?

[ThomasW]

Hi,

If you're following along you know Jon's aren't yet operational and mine have only been running since Wednesday AM. So we don't have much test data yet.

I don't believe Craig has the necessary test gear to make the measurements you requested. At this point we have on-axis FR plots of my proto's, I just need to get them off of Jon's computer

Since the biamped designs have no passive filtering, the woofer section will be as efficent as the T/S specs indicate. This means exclusive of amplifier power, Craig's woofer section is ~ 92dB. My single RSS390 is 90dB/watt/meter. I have the woofers attenuated 6dB in relation to the MT section if that helps.

Next I may move to a pair of the AuraSound NS12"s. Not for more output, but to raise the overall height of the C95-T6. I'm beginning to think the C95 not the tweeter, needs to be at or closer to ear height. Later today I'm going to set the whole speaker up on a box to experiment with this..

[gitarretyp]

That's lower sensitivity than i'd hoped to see.

A couple things i never saw posted at HT Guide: What's the intended horizontal listening axis? What are the baffle dimensions?

[Kevin Haskins]

Looks nice.... I like that BMS compression driver too. 

[ThomasW]

That's lower sensitivity than i'd hoped to see.

A couple things i never saw posted at HT Guide: What's the intended horizontal listening axis? What are the baffle dimensions?

Jon's version with the Ciare woofer is specifically designed to be driven fullrange by an Ayre AX-7e (60 watts at 8 ohms).

Here's a link to a pdf of the baffle design.

Looks nice.... I like that BMS compression driver too. 

Hi Kevin and thanks....

Yes the 4540ND is a very nice driver. Current problem is getting the ENG-1 waveguide since things are messed up with supply from both DDS and Assistance Audio

Feet added ......

[jimluu]

Thanks for the pictures Thomas.  I'm curious about the driver choices.  Is there a reason you chose a compression driver with around 113db/watt sensitivity?  Seems way too sensitive compared to the 90 or so of the woofer and mid.  I also tried to look up the ciare driver, is that a 'pro' driver?  Do you think a pair of Peavy 18" low riders ( http://usspeaker.com/homepage.htm will work as well?  Has good xmax of over 9mm, and a pair in parallel would give around 103db/watt.

[JoshK]

Hi Thomas, Good to see you over here as well.  FYI, you can post links to other forums on this forum, so long as it is for informational purposes and not for hijacking.  We aren't so egocentric to think we are completely self contained and that no other forum is worth mentioning.

I have pointed over to HTguide.com on numerous occasions when it was informative, as Jon and your work (as well as many others over there) is really a gem to the DIY speaker world. 

[ThomasW]

Thanks for the pictures Thomas.  I'm curious about the driver choices.  Is there a reason you chose a compression driver with around 113db/watt sensitivity?  Seems way too sensitive compared to the 90 or so of the woofer and mid.  I also tried to look up the ciare driver, is that a 'pro' driver?  Do you think a pair of Peavy 18" low riders ( http://usspeaker.com/homepage.htm will work as well?  Has good xmax of over 9mm, and a pair in parallel would give around 103db/watt.

Hi,

It's much easier to pad down a tweeter than any other driver...

Unfortunately the particular Caire' we wanted to use has been discontinued. The price of Neodymium has gone so high Ciare' redesigned the motor and gave it a new part number. FWIW, we buy the Ciare' drivers here  http://www.assistanceaudio.com/08_CIARE.html

It's problematic to comment about the Peavy without having at least a FR/impedance plot.

I can't imagine the need for a pair of 18"s given the system's output is limited by which Accuton driver is used. The prototype you see in the pic is using just the single PE RS390, it's output level is set 6dB lower than the mid/tweeter combination

Hi Thomas, Good to see you over here as well.  FYI, you can post links to other forums on this forum, so long as it is for informational purposes and not for hijacking.  We aren't so egocentric to think we are completely self contained and that no other forum is worth mentioning.

I have pointed over to HTguide.com on numerous occasions when it was informative, as Jon and your work (as well as many others over there) is really a gem to the DIY speaker world. 

Hi Josh,

Okay, just didn't want to step on any toes....