Rear Ported Reflex, Forever and Ever, Amen [Archive] - Audio & Video Forums

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poppachubby
04-26-2010, 03:13 AM
Hey all, I haven't started too many threads lately, but I am really pumped this time around.

To make a long story short, I was running Sound Dynamics 1200 SMT with my gear. Great sounding pair.

I switched to Dynaco A-25, even better. The Dynaco's truly are a gem as you all know. My issue with the Dynaco's after the Sound Dynamics was decreased imaging and somewhat dynamically challenged.

Last night, in what was really a "for the hell of it" move, I hooked up a couple other pairs I have.

Paradigm Model 7se.....nope, no bass

Angstrom Modular Three....that's not it

Theatre Audio Bookshelf....wha?!? What's this and why do they sound PERFECT!?!

Even on a stand that isn't ideal, about 5 inches too low, these things blew the top off my room. I was in complete awe. The bass extension was better than even the Sound Dynamics, yet tight and believable. Same for the highs, extended and so smooth. The soundstage didn't necessarily widen, but the imaging was really detailed and engaging.

The difference? They are bass reflex with a rear port. I've never experienced benefits from a rear ported speaker, but clearly there are many. I have them about 2.5 - 3 feet out from the wall using the Cardas arrangement.

I can't believe what I've been missing from the sound that my system is capable of outputting. For my room, it appears this is the way to go. Tekton have a new model out, 2 way with a rear port, I think that may be my upgrade plan.

That also makes me think that speakers with any rear firing sound/energy are superior. Thoughts?

http://farm2.static.flickr.com/1324/4552264499_44ca52e442.jpg

http://farm5.static.flickr.com/4057/4553780803_e2c07038a6_o.jpg

Ajani
04-26-2010, 03:33 AM
With 2.5 - 3 ft of space to the back wall, a rear ported speaker should do a much better job with bass... Speakers with no port or front ports are generally designed to be used closer to the wall....

Have you tried using your other speakers closer to the wall?

kexodusc
04-26-2010, 03:40 AM
That also makes me think that speakers with any rear firing sound/energy are superior. Thoughts?


The position of the port isn't a deal breaker really - front ported speakers can be subject to some midrange frequencyleak through the port and some diffraction issues - but I don't think even golden ears could hear it most of the time.

Rear ported speakers need a bit more care with placement close to walls. All said, placement of the port would be a distant second consideration to the tuning frequency.

There's plenty of good and bad examples of both front and rear ported speakers.

poppachubby
04-26-2010, 03:43 AM
With 2.5 - 3 ft of space to the back wall, a rear ported speaker should do a much better job with bass... Speakers with no port or front ports are generally designed to be used closer to the wall....

Have you tried using your other speakers closer to the wall?

Ya for sure. I played around with all kinds of configurations. The immediacy is ten fold with this pair. Even my wife came down to see what the fuss was about, and stayed in the room for a good 15 minutes. That alone speaks volumes, especially when I wasn't even playing music she enjoys.

I knew right then that I had hit on something special, as i said, immediacy that can't be quantified but instead felt and experienced.

I'm quite excited because for the first time, I truly feel the grass is quite green on this side of the fence. I've stumbled onto some next level type of ish.

poppachubby
04-26-2010, 03:46 AM
Rear ported speakers need a bit more care with placement close to walls. All said, placement of the port would be a distant second consideration to the tuning frequency.

.

Kex! What are your rules of thumb for placement? Obviously the sound will tell me, but what's your experience been?

You don't think that energy and sound out the back is affecting the mix?

blackraven
04-26-2010, 10:03 AM
Pops, you should try placing some foam plugs in the ports and see if the sound improves. It may tighten up the bass. My Monitor Audio speakers and my friends PSB Synchrony One's are ported and they come with foam tuning plugs for the ports. My MA's are rear ported and the plugs really tighten things up with out affecting the high frequnecies. It's worth a try.

By the way, nice vintage speak's you have there!

kexodusc
04-26-2010, 11:30 AM
Kex! What are your rules of thumb for placement? Obviously the sound will tell me, but what's your experience been?



Rule of thumb for placement? I don't have any now!!! Really, I have several speakers in my house right now, only 1 is front ported, but they all behave differently near boundaries. 2-3 feet from walls is a typical recommendation and is probably a good starting point. I have a smaller pair of monitors I made for my computer desk that don't really sound bad even as close as 4 inches from the rear wall - but I designed them for nearfield listening and they aren't playing to 100 dB levels either. 85 dB might be their limit and I'm usually within 1 and 2 meters at the listening point. The port in that case was really more to protect the woofer than to squeeze out extension.

For my other ported speakers I keep at least a 2 feet out from the walls and a bit more if I can - this has little to do with the port and more to do with the nature of sound waves wrapping around the speaker though.

I hate to cop out, but it really depends on the speaker and the room. Even then, what sounds better to you might not sound better to me, so you really have to play around with it yourself.

The only rule of thumb I try to follow strictly is to not let the distance from rear and side walls be equal or multiples of each other - and that's pretty easy to accommodate.

For my preferences, I find first reflections off the side wall to be far more offensive (probably because I prioritize the midrange) than the impact on frequencies proximity to the rear wall causes - but I try to take care of both.


You don't think that energy and sound out the back is affecting the mix? Not substantially.

3LB
04-26-2010, 12:33 PM
Rear ports provide a measure of baffle step correction

Stuffing a port is similar to an aperiodic vent

Yes, rear ported speakers are placement dependant. Rule of thumb - too close to walls, corners or shelves can muddy bass response. I'd say a foot from the rear wall, two or three feet from corners; you could always compensate with room/corner treatments. The futher a speaker is fron any walls, the better they're supposed to image.

rob_a
04-26-2010, 12:35 PM
Feels good to nailed a set up. In the past I have messed around with the acoustic sound stuffing in the speaker, adding or taking away, plugging the ports, and even changing out the crossover. Not HIFI, I know, who cares.

But if you love it, leave it. :6:

LeRoy
04-26-2010, 04:30 PM
I think the 8" or 9" woofer in a book shelf is "ideal".. back in the high school days I used to have 2 pair of ECI Super 8 speakers and they rocked the room. I also had a pair of Boston Acoustic Series 2 bookshelf speakers with a 9" woofer and they too also rocked the room and sounded great too for their time.

As far as book shelf placement goes I start out with measuring off the back wall into three sections and place the speakers at the outer 1/3 markers, with the back of the speakers 18" from the back wall and 30" from the side walls. Then I adjust the placement from that starting point, if I need to do so.

Glad you found some audio nirvana there with the new set-up!

LeRoy

frenchmon
04-26-2010, 04:54 PM
PappaC...my Cantons have a rear port and give off some good bass. I have them about 9 inches to 1 foot" off the back wall and about 6 feet of the side walls and I have very good imagining and excellent bass....oh and no toe in. These speakers give off more bass than my Paradign Monitor 7v3's

poppachubby
04-26-2010, 07:16 PM
Thanks for the responses guys. I'll be playing around tommorrow...