PMC IB1's close to rear wall, is this O.K.?

I don't have either of these speakers.

However, assuming that by "Proac rear porting issues" you mean too much bass boost between 80 and 100 Hz then this will be an improvement; the IB1 is much flatter in the overall bass than the Proacs, which should be a significant advantage when placed near walls or corners (where you get up to +6 db bass boost anyway).

Thanks Shadorne for your answers. By rear porting isssues I do mean the bass boost problem as I've described in other threads. This isn't really a problem when the speakers are out into the room say 4-5' but I've tried them closer to the wall and it just gets too much. I am assuming that the rear port will load up when closer to the wall but maybe I'm wrong.
Am I correct that you are an ATC user? As I mentioned at the beginning of this post, I've been looking at some PMC's which I think are similar except for the transmission line vs a sealed enclosure. Do you have experience with other British monitors such as the Spendor 100's and Harbeths?

It is hard to say if you are going to have issues with placing IB1s close to the back wall.
I have IB2 and they are approximately 4 ft from the back wall, in a room that is approximately 18X18ft of unusual shape with no corners, so I have no issues of any kind with bass, ASC tube traps did almost nothing positive in my room (I had a chance to try).
A friend of mine has IB2s less than 2 ft from the back wall, in a room that is approximately 1/3 smaller than mine, of classical shape, but he managed to get quite good performance without huge peaks and dips by treating the room acoustically (pair of 13” tube traps, acoustic panels on side walls and ceiling).

If I recall bass goes like this Spendor - Harbeth - PMC - Proac in increasing order. ATC is actually regarded as bass lean by most people compared to "average" consumer speakers that tend to be a little bass heavy (bass sells).

Sashav,

May I know what is your friend's room dimension, and the IB2's are on the short wall or long wall?

Thanks.

Shadorne, do you mean Spendor would be the most bass shy? Or is your scale based on quality as in Spendor has the best bass in general.
Thanks

Alun,

Yes indeed I was trying to give you an idea of bass strength...these are all good speakers including your existing speakers, selection being a matter of taste.

Ryder,

I cannot say with certainty, but I would guess 17X15 or so, placed along the longer wall.
He is quite close to the speakers, around 9 feet, anything closer would not be good.
The acoustic treatment did wonders in his place, there is still a tad of boomines with some material, but nothing that is detrimental.
Seems to me that with these speakers it is more important that you are at the correct distance from the speakers, and at the correct height, than the distance of speakers from the back wall.

Ryder,

As a matter of a fact, my friend used to have the same speakers as you, PMC LB1 Signature, now replaced with IB2. The rest of system remained the same, with addition of room treatment.

Sashav,

Thanks for the tip. I knew the IB2's were too huge for my room. Your friend's room is still much larger than mine. Since I can only place my speakers along the short wall, there is no way the IB2's can fit into a width of 11'.

I am not surprised that you felt the bass was tad boomy in that smallish room as the IB2 really pumps out prodigious bass. When I listened to these at low volume in a very large room(about 20'x50'), the bass is full and controlled with a sound that's well-balanced from top to bottom. I never felt anything was lacking with that setup and my perception towards PMC speakers had changed since then. I ended up with the LB1 Sigs though as these would fit perfectly in my room dimensions. I thought these sounded better than the FB1 but the IB1's just blew these little speakers away. Nevertheless, I have my speakers high-passed with a subwoofer and this takes the system to a higher league. I cannot imagine listening to any monitors without a subwoofer now.

Do let us know in your other thread if the 7B-SST's were a huge improvement over the 4B-SST when you get them.

Thanks for the usefull info. I guess it's time to go and hear them proper before fully commiting to selling my 3.8's.
Cheers