[scorpion]

Nice Bob,

Just tell us if you need new socks, I think we could spare a few.

If a bit OT: My reason for posting this is that I read your testing Augies for IB. That's an exellent choice I think. From my simus the Augie would go ruler straigth down to 30 Hz beeing 3 dB down at 25 Hz in IB with about an average 92 dB/watt effeciency. That's mighty impressive !

Also coming back to the original question: With the bafflesize stated the Alpha15 with its higer Qts will produce a hump in its response just compensating for the baffle loss and so going linear down to 40 Hz. Augies even with .92 Qts will not really match the Alphas in this region without beeing more and a bit equalized.

/Erling

[Bob in St. Louis]

Ok, cool. Thanks for more good info Erling. 

Bob

Off Topic: Erling, if you're interested in the IB build, here's a long thread about the build. I've yet to take any measurements, but I'm highly impressed so far.
http://www.hawthorneaudio.com/forums/viewtopic.php?f=2&t=1677&start=15&st=0&sk=t&sd=a

[scorpion]

Cool Bob,

Very impressive set up and arranging. However Sterling Augies are plain common Augies I presume and I don't think Darrel says anything else, because these drivers are that good from the beginning.  I objected in the Hawthorne forum to the nameing of the 'Sterling Silver Iris' because Sterling is a silver with less silver content than real silver, but that is more of a psychological question, I think.  However the Sterling units are supposed to be of a higher quality than the Silver units.

In posts lately Darrel Hawthorne explicitly says that the ordinary Augies are of Sterling quality from the beginning and that no 'Sterling Augie' will be presented. In this matter I think he absolutely right. The Augie is just a formidable OB-IB speaker as it is now also with a very decent price.  And from what I can see and read you take really good advantage of it. 

/Erling

[Bob in St. Louis]

More OT......

There are eight Sterling Augies in existance. I have four and yes, there is a very noticable physical difference between these and the "performance grade" drivers currently being sold. If memory serves, Darrel had posted the T/S parameters on the thread I linked to for the Sterling Augie.
These fifteens were a test bed, that has most likely died. Until I can get all of the final tweaks worked out of the rig and provide some eye opening numbers, there will most likely never be anymore "15 inch Sterling Augies" produced.
Darrel is now focusing on 18's instead of 15's.  aa

Bob

[kyrill]

the bigger the speaker the bigger the mass, the bigger the mass the slower the speaker is
the slower the speaker the less transparent and less good Pace and rythm

there are always trade offs. no? also bass needs to be fast, following transients, being transparent?

[alexstl]

Hello guys,  Bass augmentation is the least important factor for me.  I currently have two tube amp systems listening to two pair of cain and cain abbeys with no bass augmentation.  I want the focus to be on the lowther's single driver range for as much as possible.  Is there a simple way to augment the bass in a lowther ob?  Thank you for all the time, thoughts and energy being offered to come up with a better sounding lowther ob!  Alex 

[Bob in St. Louis]

Alex - Where are you my friend? (I have to work today, so I won't be home but I will be online).

Kyrill - Yea, kinda, sorta. Maybe. You need surface area to move air. I've got some of the tighest 'snappy' bass I've ever heard. AND at loud (but resonable) volume, I can feel my hair and my pant legs. That's nice bass.  

Bob

EDIT: oops, we were typing at the same time. 

[AJinFLA]

Bob's 9yr old is probably busy, so here ya go



the Lowther is a midrange speaker and will have absolutely no bass by itself, even on a very large 24"x48" baffle, which itself would have to be made extremely thick, to avoid playing its own tune.
As MJK suggested long ago, cross it to an Alpha 15.
(the more realistic -dark blue - DX2 data was taken from Martins article http://www.quarter-wave.com/Project04/Project04.html. The green is from the Lowther site and seems improbable )

cheers,

AJ

[scorpion]

Alexis,

We are not really talking of bass augmentation more of good loudspeaker level matching and frankly you will need bass beside the Lowthers if played on OB 4' x 2'. Alpha15s are a very good bet to complement the Lowthers.  They are fast as Hell, even faster than Augies at least compared to slow SEAS Milennium tweeters ! Kristina Lugn, a Swedish poet, is a the best slow speaker I know of and if I remember correctly I also think Alan Greenspan, former Fed chief, is another one.

/Erling

[scorpion]

Alexis,

Perhaps another comment. We are really focussing on the sound of the Lowthers when we discuss complementing them with some basspeakers. We are no Magicians able to tranform the Lowther into a speaker it isn't just by putting it on a flat piece of wood. On the other hand it may be made to sound at its very best by doing just this ! 

/Erling

[T-BAG]

OK, here are my recommended crossover options.

Each channel is a Lowther PM6A or DX2 full range driver with two Eminence Alpha 15A woofers wired in parallel.


Active Crossover Settings

Low Pass - 200 Hz 2nd order Linkwitz-Riley
Hig Pass - 400 Hz 2nd order Linkwitz-Riley


Passive Crossover Sizing (classic 2nd order circuit configuration)

Zobel circuit across the woofers
  Mills 4 ohm resistor
  Solen 30 uF

Low Pass
  ERSE 14 ga Super Q 4.7 mH in series with the drivers
  Solen 130 uF in parallel with the drivers

High Pass
  Solen 27 uF in series with the drivers
  ERSE 14 ga Super Q 5.6 mH in parallel with the drivers


http://www.erseaudio.com/Products/14-AWG-1-63mm
http://www.partsexpress.com/solen-metallized-polypropylene-capacitors.cfm


These would be my starting crossover values and I would tweak them by ear.

Hope that helps,

Martin

MLK,
Is this what we are looking at in post #17?

http://picasaweb.google.com/lh/photo/mWDz5cn_Hvr6Yyhv4yp_xA?feat=directlink

[tubesguy2]

I don't think Martin would mind if I reply to your question.  What your sketch shows is low-pass filters on both the woofs and the Lowther.  You need to switch the crossover parts on the high-pass, so that the capacitor is in series, and the inductor is in paralled with the driver load.  - Pat 

EDIT: You seem to have added another cap on the low-pass, too, as well as adding a resistor.  Not really sure of what these are intended to do.

[T-BAG]

I don't think Martin would mind if I reply to your question.  What your sketch shows is low-pass filters on both the woofs and the Lowther.  You need to switch the crossover parts on the high-pass, so that the capacitor is in series, and the inductor is in paralled with the driver load.  - Pat 

EDIT: You seem to have added another cap on the low-pass, too, as well as adding a resistor.  Not really sure of what these are intended to do.

 
Thanks Pat,
Maybe this will do do. I am not positive on the Zobel. I will be using a DX4, so I am not sure if I need to pad down or notch the DX4.

http://picasaweb.google.com/lh/photo/VDdA4h98MPWdU0F9Be3W2g?feat=directlink

[MJK]

Maybe this will do do. I am not positive on the Zobel. I will be using a DX4, so I am not sure if I need to pad down or notch the DX4.

http://picasaweb.google.com/lh/photo/VDdA4h98MPWdU0F9Be3W2g?feat=directlink

For the Zobel circuit, the 30 uF cap and the 4 ohm resistor need to be in series across the woofers. Your sketch shows them in parallel across the woofers.

A DX4 will definitely need some attenuation to match the parallel pair of Alpha 15A woofer's outputs.

[T-BAG]

Maybe this will do do. I am not positive on the Zobel. I will be using a DX4, so I am not sure if I need to pad down or notch the DX4.

http://picasaweb.google.com/lh/photo/VDdA4h98MPWdU0F9Be3W2g?feat=directlink

For the Zobel circuit, the 30 uF cap and the 4 ohm resistor need to be in series across the woofers. Your sketch shows them in parallel across the woofers.

A DX4 will definitely need some attenuation to match the parallel pair of Alpha 15A woofer's outputs.

Maybe this is closer to intended XO.

http://picasaweb.google.com/lh/photo/BHjEQxMHUraGCSA4HyHAUA?feat=directlink

BTW, any advice for getting Pics inline, putting my picassa direct link there doesn't work. Looking at help pages, I dont see if there is a size limit, or something else I maybe missing.

Mike

[MJK]

The Zobel looks better.

However, if you put a resistor in series with the DX4 you will also need to change the crossover component values since they are a function of the driver voice coil resistance. That would be one option.

The second option would be to size a L-Pad which is a resistor in series combined with a resistor in parallel with the driver, between the crossover and driver. The combination of a L-Pad and the driver should yield a resistance value equal to the driver's voice coil resistance so the crossover components would not need to be recalculated.

Nothing is ever easy.

[T-BAG]

I've done L-Pads before to mellow an input on an older pre-amp. I will have to lookup their application here as far as lowering I assume 3-5db. I should probably rig a few pots in their to get the best value.

Here is my current OB, with Old Definimax LO15's in there.

http://picasaweb.google.com/lh/photo/UAO1dbzeUinNpkQJfo4kZA?feat=directlink

Here are the proposed mods to it. Totally unsure of tweeter location, but to recycle these panels, I need to use existing holes.    I am going to try to borrow some PM6A's, as I heard they perform well here.

http://picasaweb.google.com/lh/photo/ZscrU8oebBDrXzYwQeFtzw?feat=directlink
http://picasaweb.google.com/lh/photo/Qs7F0jcUjMqQiAlTt6CGPg?feat=directlink

[Rudolf]

Totally unsure of tweeter location, but to recycle these panels, I need to use existing holes.

I would mount the Fostex straight above the Lowther.

[T-BAG]

On to hijacking thread.....

Here is the notch filter, high pass for tweeter, and tweeter xo as it currently sits.
I assume that putting the high pass filter in front of this will yield some totally different results....

Is there a way to keep this functionality? I think the 'end' of the XO acts as 10hz low pass for tweeter.
Excuse my massive XO ignorance..
Mike

http://picasaweb.google.com/lh/photo/_Zlsn6TcZFQYr2bSLKPhig?feat=directlink