FR125S/SDX7 2-way

[RAW]

That is the laws.
Want large out put from a driver you need volume or EQ.No way around it.

Over all the cabinet does not need to be that large, as a fact with room placment issues for most people location is close to a wall.The room issue can make a smaller cabinet more enjoyable.

But then some lust like low end extention

[CSS/XBL]

In this case the SDX7 was designed as a specific replacement for an existing product. There are both technical and physics related limitations and interactions which contribute to each type of design as Al has suggested.

Bob

[simon5]

Hi, I would like to know why the SDX sounds better please.

Lower distortion ? Better high frequency response ?

I'm curious since the Extremis had a lower Le.

[RAW]

the SDX7 I just put them in last nite! Not Bad...actually very good! There is more control and punch. The upper end seems to have improved??? How can this be or did it? Is this me? Is this what was to be expected?I am using a new (used) amp from Pass Labs - X250. This amp made these speakers grow two - three times their size. The mids and bass are phenomenal! The HT3's LOVE power!

The cone is a lot stiffer on the SDX7 which will lower the distortion due to the cone not flexing.
Plus the newer XBL^2 motor design on the SDX7.

Anyone how has listened to them here in the one of our designs drop in no crossover change (due to the low crossover point) is shell shocked at the difference between the Extremis and the SDX7.

This comment aboe is a customer who we just sent new SDX7 woofers to for his speakers which used the Extremis.

[simon5]

Thanks for your explanation ! But wasn't the Extremis also XBL^2 ?

[planet10]

Originally posted by Digeridoo
FYI, here's a photo of a version of the small aperiodic boxes I did for the FR's a while back -- I keep meaning to get around to putting these up as a thread and drafting up a set of enclosure plans, but between a new start-up business and an 18mo old start-up human, those good intentions somehow keep going by the wayside....

I REALLY like your execution... can i use that picture in the next rev of the docs?

dave

[planet10]

Originally posted by DcibeL
Looks quite nice, except for the low sensitivity (SDX7 advertised as 85dB@1W/1m).

One thing I never really understood about these high excursion mid bass drivers is that while they are capable of producing a lot of bass for their size, they still seem to require a large cabinet in order to do so. If the cabinet size remains large, why not use a larger driver, which will no doubt have higher sensitivity?

Hoffman's Iron Law.

What i really like about the SDX7 is that it will work REALLY well in a tiny sealed box. Use of room gain or a little EQ and you can feel bass (even just 1 in my big room -- that was a BIG surprise). I have designs on the table for single (17-21 litre sealed) double (28 litre aperiodic TL) & quad SDX7 (28 litre aperiodic), and am playing with the idea of a tiny aperiodic woofer (<7 litre).

And as good as it is out of the box, i think i have made it even better (stay tuned -- i'm working to get Bob & Al a pair this WE to play with and give feedback on)

dave

[RAW]

Originally posted by simon5
Thanks for your explanation ! But wasn't the Extremis also XBL^2 ?

Yes the Extremis was a XBL^2 motor.But the SDX7 is a newer designed motor than the Extremis.
Plus triple copper rings in the SDX7 motor.Along with the frame on the SDX7 woofer has a TON more venting under the spyder as well as in the posts for the frame


Just to name a few things.

[RAW]

Tim

How about list to them for a few days then pull the FR drivers out and send them to Dave for Enabl.

Think you will like them even more.

[Timn8ter]

The final cabinet size is a combination of getting lower frequency response from the FR on the OB, providing the volume I desired for the SDX while trying to keep it from being too wide (simple aesthetics).
It was not possible to make the speaker any shorter under these criteria due to the relatively small volume of the pipe.
The wings prevent a hump from occuring before the natural roll-off of the driver. I discovered this while working with the Tang Band W3-871S on an open baffle. I experimented with different sizes of wings before settling on these which are 4" deep (the TB W3 uses 3" deep wings).
The FR125S exhibits a beautiful curve and roll-off at 200Hz with a single cap and had my goals been different I would've considering going that direction. In this case, I wanted to stay away from the huge cap and coil values that would've been required for a passive on the SDX. Another option is going active but I wanted to stay with a single amp and passive XOs.
I'm driving this speaker with my EL34 push-pull. The FR125S mids are wonderful with this amp.