understanding speaker ports etc...

[Paul.]

Hi all,

I want to learn more about speaker positioning and how speaker design of ports etc affect its sound. Can anyone recomend a good resource?

 

[chebby]

I want to learn more about speaker positioning and how speaker design of ports etc affect its sound. Can anyone recomend a good resource?

On the forum our very own AEJim is an excellent resource.

I also remember that WHF's technical editor Ketan Bharadia designs/builds his own speakers so may be able to help point you in the right direction.

 

[Paul.]

Thanks, any help from forum regulars would be great. I've recently moved house and by trial and error my system sounds alot better than it did before. I would like to figure out why it sounds better so I can replicate it in the future. I plugged the rear ports on my BR5s as the speakers needed to be uneven distances from a wall, the right speaker sat in front of a cast Iron fire place which is less than ideal. Much to my surprise the bass didn't change much but mids and imaging improved greatly over the uniform setup in my old house without the ports plugged. I would guess that the Tweeter and mid share a different cavity to the lower bass cone and lower front port on my speaker?

The old setup is in the link in my sig, will get new pics up as soon as I have tamed the ravaging hoard of boxes and finished unpacking.

 

[Frank Harvey]

Thanks, any help from forum regulars would be great. I've recently moved house and by trial and error my system sounds alot better than it did before.

There will be individuals that will take issue with your findings unless you back it up with blind ABX testing :bigsmile:

The rear ports of the BR5's affect the mid/bass driver (top one at the front) - yes, this one will affect the imaging and detail, and more the upper bass and midrange frequencies. The front port, which won't be affected very much by the wall boundary affects the lower bass driver, which will be dealing with lower bass. The port for this only needs to be bunged if the bass is too overpowering.

 

[Paul.]

There will be individuals that will take issue with your findings unless you back it up with blind ABX testing :bigsmile:

I've been there nearly a week, I think the building just needed time to burn in 🙂

 

[Craig M.]

did you try plugging the ports at your old place? it sounds as though you have reduced the amount of upper bass and so can hear the midrange more clearly, the imaging and other improvements were probably always there but masked by other frequencies. or maybe it's just the new room has better acoustics and the speaker and seating position are better. your rooms acoustics are arguably more important then the kit you have in determining sound quality.

 

[Paul.]

I want to read around the subject a little so I can reverse engineer what I have done. I never plugged the ports in my old place, but did use the system for a week in my new place without plugs. I understand what is happening, I just want to know why it is happening.

What you suggest sounds about right. In my old place My speakers were on rubber feet direct on to wood. The new place is carpeted and I have spikes -> tile -> carpet. I was quite disappointed as I was expecting to notice an improvement with the reflection reduced on the floor and I was expecting bass to tighten up because of the spikes-> tiles. But nothing happened, it sounded identical (if not slightly worse) than my old place. I then tried the plugs as a last ditch thing, thinking it would only affect the bass. The only reason I tried the plugs was that the lopsided setup worried me. Was pleasantly surprised by the results. If the bass frequencys were trampling all over the modifications I had just made, that would make sense.

 

[The_Lhc]

I'd have thought tiles on top of carpet would make for quite an unstable base, I've always assumed spikes are for punching through carpet to get to the solid floor underneath, that's what I've done anyway (but I've got concrete under the carpet, not floor boards)? Not to mention spikes on tiles are going to slide around aren't they?

If you had a granite block or something of similar mass then maybe but I don't think tiles are going to secure everything in place well enough.

 

[Paul.]

Its wooden floor boards, and there is a flat underneath me. Hoping this would help isolate them from my tunes. The tiles are pretty substantial, they are 45cm x 30cm and pretty heavy. The speakers will slide if knocked hard, but everyone who is trusted to come in to my home knows to stay the hell away from my speakers!

 

[oldric_naubhoff]

did you try plugging the ports at your old place? it sounds as though you have reduced the amount of upper bass and so can hear the midrange more clearly, the imaging and other improvements were probably always there but masked by other frequencies.

A+

I've noticed the same relation. I don't plug ports in my speakers and keep them about 2 ft away from back wall (that way they re not too obtrusive). but when I want to realy listen to music I take them more into the room (about another foot or slightly more) and imaging improves significantly.