A couple of questions on my new speakers

[HAVIC]

Just a few questions about the setup. I got the PSB Image T65,C60,S50 speakers setup. I have them hooked up to my Yamaha RX-V2500 and they sound great however... The Center Channel (Image C60) has a lot of extra insullation that I can see through the left vented port. I called PSB and they said that it is fine but will not cause any audio quality problems and that if I want to I can push it aside with a pencil. I tried to do this last night but the insallation is to thick and just bounces back to its original locations. The insulation covers about 75% of the port.

Also I now that I have 6 ohm speakers connected to my Yamaha reciever I put the reciever on 6ohms. Since then I have had to raise my reciever to higher volumes to get the same volume as my 8 ohm speakers. I think this is normal from what I understand but I could be wrong. I believe the reason is because 6ohms require more power to drive them. Is this right. Thank you.

Greg

[kexodusc]

Hi Greg:

With regards to the insulation, I don't know exactly where the port is on that speaker, but I would advise you to be careful pushing it with a pencil...especially if it's behind a woofer. A lot of woofers use vented pole pieces at the back of the woofer as an integral part of the design. If the insulation gets to close to this (2 or 3 inches even) it can really affect the performance in some woofers. I found this out the hard way recently with my sub - couldn't figure out why a 92 dB efficient 15" woofer wasn't playing loud - I thought people were kidding when they said polyfill behind that screened vent could mess everything up...man I was surprised - and embarassed.

Can you clarify, does the fill cover the inside end of the port or can you just see it?
Covering the port isn't good either....it could possibly change the tuning frequency, cause port noise, and even affect volume at some frequencies. But, depending at what frequency you cross the speaker over it might not matter...if you cut the LFE off at 80Hz I'd probably not worry about it. Or just get some needle nose pliers or scissors and manipulate it out of the way. Sounds like the stuffing might have come loose? If it's just a bit (golf-ball sized loose fill) you could just pull it out if you want, but be careful not to upset the rest of the fill inside.

If you just see it there, and the speaker sounds okay, I wouldn't worry about it...fill is usually an integral part of the speaker design - some use more, some use less. Being able to see it is okay...

[JSE]

Can you exchange the speaker? You might want look at another actual speaker where you bought it from and see if it has the same issue. If not, give some of the reasons Kex mentioned above and explain that you want a new "perfect" speaker. I bet they will exchange it for you. Plus, now that you have seen the insulation, you will stare at it all the time. :D

JSE

[jasmit]

I agree with kex and JSE. The airflow through that port must be unrestricted in order for the speaker to sound like it is designed to sound. As it is, I would characterize it as a defective speaker which the dealer should exchange without any questions.

[HAVIC]

I can not exchange it as I bought it direct through a wholesaler and got 40% of MSRP of the speakers. I had to inspect them at the warehouse and sign off on them, but did not notice it until I got home. When I get home I will upload a picture and see what you experts think.

Also not that I don't believe you guys but it bothers me that the PSB said there would be no sound quality problems and you guys think it is possible.

[kexodusc]

Also not that I don't believe you guys but it bothers me that the PSB said there would be no sound quality problems and you guys think it is possible.

There's a big difference between being able to see the damping material and it physically blocking or being inside the port tube.
If the tube's end is not obstructed there shouldn't be a problem - it's quite normal to be able to see the fill.

[JSE]

Also, a little port blockage may or may not be a bad thing. They actually make port plugs so you can "tune" a speaker. Just a side note.

JSE

[kexodusc]

Also, a little port blockage may or may not be a bad thing. They actually make port plugs so you can "tune" a speaker. Just a side note.

JSE
That's true, though some woofers don't take kindly to being in boxes tuned above their Fs. But a tiny bit of fill in the port isn't necessarily going to make the speaker sound much different. Hopefully we can get a decent picture up to see what we're up against.
No need for unecessary panic. I have a feeling this is probably nothing to worry about.

[HAVIC]

tell me what you think. Thanks
Greg

[JSE]

I don't think that would effect the sound any. Looks like there is room between the fill and the back edge of the port. Also, looks like the grill cover would cover the port so seeing the fill should not be a problem.

JSE

[kexodusc]

Yeah that doesn't look too bad...there's some good clearance there. If it really bothers you get some long pliers or scissors or the pencil and move it a bit cut a small section out and remove it...won't affect sound any. The port's beside the woofer so there shouldn't be anything too delicate behind the port. Ideally there should be a good 1/2 inch or so clearance, hard to judge the depth in the photo...but that's not too packed or completely blocking off the port. Shouldn't be a problem at all.
Looks like R40 pink fiberglass.
Like I said, if you use your receiver to crossover the speakers at 80 Hz or higher it's probably not making a difference anyway.

[Geoffcin]

I just checked the back of my only ported speakers the JAS Orsus I'm doing a review of, and there's a tube about 4" long attached to the end of the port flanged hole.

[kexodusc]

Geoffcin - looks like they're 2 pieces in that. It's quite common to see separate port/flare pieces...being one piece and perfectly smooth isn't going to reduce diffraction or anything on the air movement and low frequencies. It's common to see the ports countersunk into the cabinet wall and a port flare or cover too. The flare/fflange covers help reduce air noise and offer a bit better tuning precision.

It probably helps considerably in the manufacturing process to install the tube first, veneer/finish, then add the port covers as the final step.

[kexodusc]

Is that a white PVC port tube and a black flange though?

[Geoffcin]

Geoffcin - looks like they're 2 pieces in that. It's quite common to see separate port/flare pieces...being one piece and perfectly smooth isn't going to reduce diffraction or anything on the air movement and low frequencies. It's common to see the ports countersunk into the cabinet wall and a port flare or cover too. The flare/fflange covers help reduce air noise and offer a bit better tuning precision.

It probably helps considerably in the manufacturing process to install the tube first, veneer/finish, then add the port covers as the final step.

I was wondering why the ports on the back of the Orsus also are two piece. I guess it really doesn't make a difference either way. Don't tell that to B&W though!

[kexodusc]

Well, sometimes these "precision ports" are considerably more expensive and don't really add enough value. Sometimes they're the difference between pulling off a design or making a compromise somewhere. IIRC, they precision flared ports can be a bit shorter and still achieve the same results a longer cylinder port tube can make...you can see why this could be beneficial in smaller cabinets where a 12" port tube might not be practical.

I think B&W is big enough to manufacture their own plastic, one-piece port tubes cheaply. Paradigm still uses the cardboard cylinders you find in toilet-paper rolls in some of their speakers - which is fine unless things get damp (and then you've probably got bigger concerns).

If they could ever make a home-use plastic-molding kit for shaping the internal line in a transmission line speaker I'd buy one tomorrow. :D