Speaker Placement - This Luddite has been converted

[NJB]

This will bore those who have been working this angle for years, but over the last week I have learnt a lesson that has saved me a lot of money.

i have been looking for new speakers, auditioned several, and been living with a pair of Dynaudio Excite X12s that a mate loaned me. I liked the treble and the bass was plentiful but for some reason it just did not come together. The bass was overblown and it was upsetting the whole balance and making for a very tiring listen.

i had been looking for advice and I had stuck to my normal rules for rear ported speakers, i.e. Spikes to the floor and blutack on the top plate of the stand. Then away from the wall and a little toed in. Except, this time, it did not work and I had basically given up until the experts on room acoustics and placement got their teeth into me.

It turns out that my speakers had a small hump in their upper bass response that coincided with the size and acoustics of my room. My attempts to resolve the issue, based upon trial and error, made it worse.

So I followed advice and the speakers are now as close to the rear wall as the wires will allow. The foam bungs are in the rear ports, and the close proximity of the rear wall is giving me all the tight bass that I want and made this little speaker really sing.

So my lesson is to be more open minded and not to give up too easily.

 

[manicm]

Glad it worked out for you but port bungs are usually a hit and miss affair, it didn't work too well for a pair of 685s I had. And these were front-ported.

 

[FennerMachine]

Well, in this case it was a hit!

If it works for you and you have the sound you can achieve for your budget then Nice One!

 

[iQ Speakers]

Its paramount! Along with chosing the correct sized speaker for your room. Well done you. Unfortunatly its not contravercial or about cables so you will have very few replies.

 

[davedotco]

I say this from time to time but the myth persists, so I will say it again.

The position of the port makes no difference in terms of distance from the backwall, unless you get real close with a rear firing port, 3 or 4 inches maximum.

The only thing that makes a difference is the speakers polar response and that is in the gift of the designer. Bass tends to be omnidirectional, high frequencies are not so the balance is only correct if the positioning is as designed.

The only 'wrinkle' is possible cancellation in the mid bass if the rear radiation is reflected such that it is out of phase with the direct signal from the front facing speaker. I have encountered this issue on occasion but it is rarely a problem in hi-fi setups.

 

[NJB]

Its paramount! Along with chosing the correct sized speaker for your room. Well done you. Unfortunatly its not contravercial or about cables so you will have very few replies.

Yes, I guess you are right, but this seemed a bit controversial to me. Putting the foam bungs in the speakers made them into a semi sealed box design; I appreciate that the open cell foam still allows a little leakage at some frequencies. My first thought was that this was a bad move, but once it was moved against the wall and the aperiodic loading effect kicked in then the sound suddenly changed.

I just wanted to share, as I have received a lot of good advice from forums, and there might be people who find that this works for them too.

If you want controversial then I use NACA5 cable (hence a limit on how close they can get to the rear wall due to the bend radius). Also, I could not buy BluTack and had to use a local equivalent which is white; perhaps this is why the speakers sound better, and the placement is coincidence?

 

[Laurens_B]

I say this from time to time but the myth persists, so I will say it again.

The position of the port makes no difference in terms of distance from the backwall, unless you get real close with a rear firing port, 3 or 4 inches maximum.

The only thing that makes a difference is the speakers polar response and that is in the gift of the designer. Bass tends to be omnidirectional, high frequencies are not so the balance is only correct if the positioning is as designed.

The only 'wrinkle' is possible cancellation in the mid bass if the rear radiation is reflected such that it is out of phase with the direct signal from the front facing speaker. I have encountered this issue on occasion but it is rarely a problem in hi-fi setups.

I am wondering then, why are not all speakers rear ported? Only because of the (small?) possibility of out of phase cancellation? Rear ported seems superior because there is less chance of port "chuffing", so why are so many speakers front ported?

 

[yani]

I have a pair of Celestion A1 (14 years old now). I was in the market for new speakers and during this process looked into best placement etc. I realised at that point the Celestions (after all the years I had them) could have been better placed. I did the opposite to you by moving them further away from the back wall and slightly closer together. This gave me the perfect equilateral triangle to my sitting position. Bingo. The difference was really obvious. The bass better controlled with a wonderful deep and expansive soundstage. Something I really appreciate. I ended up keeping my old speakers !!

Placement does matter. How many people out there pay big bucks for speakers and dont take care to get the best they can from their investment?

 

[davedotco]

I say this from time to time but the myth persists, so I will say it again.

The position of the port makes no difference in terms of distance from the backwall, unless you get real close with a rear firing port, 3 or 4 inches maximum.

The only thing that makes a difference is the speakers polar response and that is in the gift of the designer. Bass tends to be omnidirectional, high frequencies are not so the balance is only correct if the positioning is as designed.

The only 'wrinkle' is possible cancellation in the mid bass if the rear radiation is reflected such that it is out of phase with the direct signal from the front facing speaker. I have encountered this issue on occasion but it is rarely a problem in hi-fi setups.

I am wondering then, why are not all speakers rear ported? Only because of the (small?) possibility of out of phase cancellation? Rear ported seems superior because there is less chance of port "chuffing", so why are so many speakers front ported?

Originally I think it was simply the way speakers were built, all the cutting etc being done on the one baffle, in some speakers the same enclosure could be used to produce different speakers.

In many ways you are correct, rear porting may reduce the audibility of 'chuffing', also reduces the possibility of mid-bass transients from the rear of the cone being reflected of the rear panel and out through the port. The phase issue should not really be a problem anp placing the port adjacent to the bass driver may allow the in phase output of the cone and the port to 'couple' and be a little more effective.

Really though their seem to be no obvious reason one way or the other, though some speaker designs have tried to hide the port by making it downward facing,

Looking at the above you can see the variations in polar response with frequency, at bass requencies the response is near omnidirectional clearly demonstrating that the position of the bass driver or the port is of minimal consequence.

 

[lindsayt]

NJB, have you thought about going the whole hog and trying a pair of sealed box speakers?

 

[SteveR750]

NJB, have you thought about going the whole hog and trying a pair of sealed box speakers?

Beat me to it! You can pretty much stick them anywhere (room modes etc all being equal) and there's nothing quite like a natural roll off

 

[NJB]

The short answer is no, not at the moment. I was looking to see if I could use the speakers that I had available to me rather than splashing out. As I have the sound that I like now then further adventures are not imminent. However, I can appreciate what you are saying about it being the logical move if I do decide to move on.