[WallyWest]

Just thinking out loud here. 

Would a pair of M-165X drivers work well in a transmission line configuration?  Kinda like the AV-3, but just for those two drivers.  My goal is really awesome mid-bass performance.  Doesn't have to be quite a stand alone speaker, I'd still use a separate sub.  Basing it on the AV-3 design I assume it would need to be bigger.  Any idea on what dimensions would be necessary? 

Then I'd stick the OB-5 open baffle MTM on top of it. 

Good idea, bad idea? 

[EARGASM]

Removed by member.

[Danny Richie]

Would a pair of M-165X drivers work well in a transmission line configuration?

The impedance is too low for you to run the two of them in parallel. You can run them in series but the sensitivity will be low.

I have a design on the drawing boards that I hope to get to soon that will use a Neo 3 pdr up top and a single M-130X in an open baffle. I will then use a pair of the M-165X woofers in series below it in a sealed box. Sensitivity will be in the 85db range. It should be a really great sounding speaker for a small room.

[fcraven]

Would a pair of M-165X drivers work well in a transmission line configuration?

The impedance is too low for you to run the two of them in parallel. You can run them in series but the sensitivity will be low.

I have a design on the drawing boards that I hope to get to soon that will use a Neo 3 pdr up top and a single M-130X in an open baffle. I will then use a pair of the M-165X woofers in series below it in a sealed box. Sensitivity will be in the 85db range. It should be a really great sounding speaker for a small room.

mmmm. that sounds tasty.

[WallyWest]

The impedance is too low for you to run the two of them in parallel. You can run them in series but the sensitivity will be low.

Ah, so in parallel they'd be 4 ohm right?  So parallel or series could work if the amp is up to the task. 

I guess where I got confused was on the OB-7 page where it says you can substitute the M-130x if you want to.  Does this mean you have a 16 ohm version of the 130x, or do you wire it differently when the 130x is used? 

[Danny Richie]

Ah, so in parallel they'd be 4 ohm right?

Actually with a DCR of 5.6 ohms it makes a pair of them drop to 2.8 ohms, and that is a little bit too low.

I guess where I got confused was on the OB-7 page where it says you can substitute the M-130x if you want to.  Does this mean you have a 16 ohm version of the 130x, or do you wire it differently when the 130x is used? 

The OB-7 uses four of them in a series parallel configuration. So the impedance is the same as if you were using only one of them.

[William Schuchard]

Would a pair of M-165X drivers work well in a transmission line configuration?

The impedance is too low for you to run the two of them in parallel. You can run them in series but the sensitivity will be low.

I have a design on the drawing boards that I hope to get to soon that will use a Neo 3 pdr up top and a single M-130X in an open baffle. I will then use a pair of the M-165X woofers in series below it in a sealed box. Sensitivity will be in the 85db range. It should be a really great sounding speaker for a small room.

I have something similar that I made with some help from Danny.  It's a single M130X on top with a Neo3 PDR but a single M165X on the bottom.  For what it's worth, it really is a great sounding speaker.  Using two woofers on the bottom is a good idea as I can bottom the single M165X with certain music and a simple Bryston B100 SST.  I originally had a little trouble getting the midrange level set correctly but in the end I am very pleased.  These work great in my small listening room.  On axis response has a little spike around 10Khz but as soon as I go just 5 degress off, it's surprisingly flat in the listening window.

For those that are curious, I originally used too large an inductor creating a bit of a BBC dip and the inductor had too much DCR lowering the response of the entire mid a bit.  I had wound them myself out of too thin a gauge wire and decided on the BBC dip on a whim.  The combination of having the M130X level too low and the top end of it's range shunted too much made it sound nice with some music but it was a little colored.

I broke out my SpeakerTester (part of the real WooferTester) and simulated the crossover using a better value and lower DCR inductor for the mid.  Danny was only too happy to send along the new inductors.  Once installed, everything snapped together quite nicely.  Since making that change a few months ago, I have spent my time just listening to music instead of starting some new speaker project.  These are revealing, smooth, and pleasing to listen to.  I actually get compliments on the look from people who would normally not even want to see a speaker in a room.  I think Danny called a similar prototype he had an OB3-X by the way.  I called mine a pseudo-OB3-X when speaking with Danny but my wife calls them Hillary due to the large rear.

Regards,
    Bill

[corndog71]

Would a pair of M-165X drivers work well in a transmission line configuration?

The impedance is too low for you to run the two of them in parallel. You can run them in series but the sensitivity will be low.

I have a design on the drawing boards that I hope to get to soon that will use a Neo 3 pdr up top and a single M-130X in an open baffle. I will then use a pair of the M-165X woofers in series below it in a sealed box. Sensitivity will be in the 85db range. It should be a really great sounding speaker for a small room.

Sort of a mini-x-statik!  That sounds like a cool idea! 

Have you ever thought about using 8" drivers for mids/woofers?