Plugging ported mains with subs and 2 way active Xover

[Matt501]

Hello everyone:

What are your thoughts on using plugs in ported mains to address phase coherency issues when mating to subwoofer output?

This is 2 part -

1) the resulting sound and
2) impacts on designed use - IE do you present the opportunity for harm to the speaker as drivers for ported uses are not designed for sealed applications (I am regurgitating read material here)

To be more specific I am using Bryston Mini T's with 2 JL Audio E112 subs and a JL Audio CR1 active 2 way crossover.

Set at 24db slopes and high/low crossed at 95hz (well above port tune).

Manufacturer told me it doesn't matter either way, especially when crossing over above the port.
Totally enjoying the addition of the 2 way crossover and the resulting cleaned up bass and overall system headroom and clarity gains - surprising actually.

In any case I'd welcome some input/advice and experiences had.

In short:
What do you think of plugging ports?
Can it prove to be damaging?

Thanks!!

 

[Matt501]

Sorry, additional question -

If crossing over at 95hz (I haven't tried this experiment yet) would you run with the plugs in or out?
I was advised by my dealer that above tuning frequency the ports would be "invisible" and therefore it wouldn't matter plug in or out.

Thoughts?

 

[TLS Guy]

The F3 of those speakers is 33 Hz, and it has an 8" woofer. It will not make any difference if you plug the port with crossover above 60 Hz.

When you plug the port, you will have a sealed speaker with an over sized cabinet. It will likely raise F3 to 65 to 70 Hz. Damage would only occur if you plugged the port and the equalized the speaker back to an F3 of 33 Hz.

Your real problem is that you have a three way speaker with crossover to mid at 160 Hz.

So if you crossover at 80 Hz you will have two crossovers only 1 octave apart. At 95 Hz they will be less than an octave apart.

It is highly desirable to have crossover at least 2.5 octaves apart and ideally 3 octaves or more apart.

It is really difficult to get a smooth response will closely spaced crossovers and you almost always get a troublesome band pass peak.

In addition I think it is poor practice to design speakers with passive crossovers below 350 to 400 Hz area. The large value components tend to cause all sorts of havoc.

I suspect the benefit you notice is that you are getting much less sound from the woofer, which likely is suboptimal because of the issue I site.

So I would ignore the port issue, and play with the crossover point and see what sounds best.

You should also try using your speakers full range and bringing the sub in at 60 Hz and see how that sounds. If it were not for the problem of that low pass passive crossover that should be ideal.

 

[BoredSysAdmin]

In addition I think it is poor practice to design speakers with passive crossovers below 350 to 400 Hz area. The large value components tend to cause all sorts of havoc.

... Bryston hasn’t made a speaker in the half-century they’ve been in business. What began as a pet project for VP of Sales and Marketing James Tanner evolved into a collaboration with Canadian loudspeaker specialist Axiom Audio...

Source: http://www.soundstageaccess.com/index.php/equipment-reviews/526

So sales person decided to start to selling speakers without talking to real engineers (or he did and was told it's a bad idea) ... What could possibly go wrong?

I think I'm starting to see where the source of such "interesting" design - apperently it's from same company who though that two horizontally placed tweeters in center is a great idea

 

[Matt501]

Yeah the more I learn the more I begin to question it as well.....

Would you guys recommend going for the lower crossover - toward 60hz with no plug in to try that out? I will experiment.

What do people like for a good solid speaker to mate with subs - in the monitor size range - meaning stand mountable for WAF.

I keep feeling like I need to find a totally sealed speaker with different cross over points. Am I crazy?

This hobby is humbling...

 

[lsiberian]

I don't know the size of the ports, but plugging them if done properly could potentially improve SQ. I wouldn't do it on a speaker costing this much. If you want to mod speakers get the Infinity Primus towers and play with those. This is a strange design IMO.