Dr. Spec..check this out, interesting

steveinaz

Here's the sweep with the Athena's ports blocked (no SVS) and the tones sounded much more distortion free/less resonant:
(there's a dual-plot further down)

steveinaz

Here's the Athena's with the ports open (no SVS):

tryrrthg

You've turned your speaker into a sealed design, raising it's F3 and it starts it's natural roll off a lot higher. Since the speaker is rolling off sooner you aren't seeing the room gain hump like you would with the ports open, instead the room gain is bringing up your response from it's roll off and giving you a flatter response. This is similar to what I explained about the 16-46 and 20-39 subs. you'll get similar results if you start plugging ports on your SVS.

I can plug my ports on my dyns but have never tried it. I'll have to give it a try.

Nice looking curve by the way!

steveinaz

Do you think blocking the Athena ports might make it easier to integrate/blend the SVS?

Also, the bass was much tighter/cleaner with the ports blocked, what of this? Especially the super-low frequencies...

tryrrthg

ah, you didn't have that second graph posted when I wrote my first reply. you should be getting better extention with the ports open... that's weird...

steveinaz

between 45 and 65Hz it is up about 3dB with the ports open...

tryrrthg

you've got a nice flat curve with both plots I don't think you'll have any trouble integrating the SVS. it looks like you've got no room gain problems with the Athenas. The SVS will probably give you a hump in the lower frequencies but should integrate with your system very easily.

EDIT: try and post both plots on the same graph so we can see them plotted together.

steveinaz

Cool, thanks bud for all the advice, much appreciated. The SVS comes today, so I'll get some plots posted later...

steveinaz

Here's the AS-F2 ports open/closed for comparison:

PolkThug

Originally posted by steveinaz
Also, the bass was much tighter/cleaner with the ports blocked, what of this? Especially the super-low frequencies...

I found this to be true for car subwoofer boxes as well.

monkeyphant

you've got a nice flat curve with both plots I don't think you'll have any trouble integrating the SVS. it looks like you've got no room gain problems with the Athenas. The SVS will probably give you a hump in the lower frequencies but should integrate with your system very easily.

I should have mentioned this in my PB2-ISD Calibration Thread: I am using the Athenas AS F2s with my PB2 and I have had no problems integrating Athenas (with ports open) and the SVS. The SVS should give you a hump in the lower frequencies.

MP

Dr. Spec

Distortion in a ported design always increases below the tune point because the cone excursion goes up drastically when it decouples from the resonator and the enclosure lacks sufficient restoring force.

Well above the tune point, a vented enclosure acts much like a sealed enclosure from a response standpoint.

A sealed design will exhibit a linear increase in driver excursion as the frequency drops, and will only have one resonance point (that of the woofer itself), vice two resonance points for the vented design.

A sealed design will probably have a higher distortion than a vented design at/near the tune point, since cone excursion will be minimal and tightly controlled at the tune point with the vented design. Below the tune point, the vented design might very well start to eventually exhibit worse distortion since cone motion will be not well controlled vs. the sealed unit which will always have a progressively stiffer air piston to work against as the frequency drops.

The difference in SPL over most of the curve is probably purely an efficiency issue - the sealed design is not known for its high efficiency, especially in a smaller enclosure. It will take 2X the amount of power to drive the sealed Athena to the same SPL as the vented Athena. Not a good thing when you want loud playback.

I would stick with the ported design as intended by Athena. If you want to protect the woofers and not send them a full range signal (and conserve lots of amp power in the process), then you could certainly high pass them (and low pass the SVS) at say 50 Hz with an ICBM. That would considerably reduce IM distortion from the Athena's and noticeably improve the midrange.

That's why I wish more two channel pre/pros came with a digital BM circuit.

Doc

steveinaz

I hardly see how a missile is going to help my speaker situation, Doc! kidding!!!!

errrr...what's an ICBM?

monkeyphant

Check out this review.

http://www.soundstage.com/revequip/outlawaudio_icbm.htm



MP

tryrrthg

As an alternative to the ICBM check out the Paradigm X-30 x-over. it comes with the Servo 15 and also does a good job.

REVIEW of X-30 in a Servo 15 review

It can be had for around $100 used...