Speakers for against a wall

ItsNotAllSnakeOil

Active Member
Just an update on this guy's. I've done some experimenting as I really don't want to get rid of the Dali's unless I can replace them with something much better and not sure standmounts will be less invasive. Anyway I've found that if the speakers are pretty much as close to the wall as the banana plugs will allow, there isn't really any bass boom at all. If they are a little further forward then it's worse unless they are much, much further forward which I can't do. It's like given a bit more room to breathe and it's worse up until they are way forward in the room. Anyway, pretty happy for now. Would be interested to see if anybody else has experienced this or if I'm going mad.
 

Helix Hifi

Well-known Member
Just an update on this guy's. I've done some experimenting as I really don't want to get rid of the Dali's unless I can replace them with something much better and not sure standmounts will be less invasive. Anyway I've found that if the speakers are pretty much as close to the wall as the banana plugs will allow, there isn't really any bass boom at all. If they are a little further forward then it's worse unless they are much, much further forward which I can't do. It's like given a bit more room to breathe and it's worse up until they are way forward in the room. Anyway, pretty happy for now. Would be interested to see if anybody else has experienced this or if I'm going mad.
Very strange indeed. It should be the opposite. The longer away from the walls less bass boom you get. More focused midrange, treble. Depth also improves. Still again Dali tunes their speakers to be placed really close too the walls.

Break in is perhaps is the cause. Standing waves. How is the bass response if you stand in the room? Can you measure the sound with some software?
 

Helix Hifi

Well-known Member
What is the distance between each speakers?
 

Baron Mole

Active Member
Just picking up on this thread to say that I’ve had success in the past by tuning bass ports with a collection of different sized drinking straws, cut to length and held together by tape. Could be worth a try.
A very novel idea :thumbsup: - effectively putting lots of smaller ports in the big port.

I wonder if there's any research on this - from a theoretical viewpoint it would be a mathematical nightmare -probably need to book time on the world's biggest supercomputer. :rotfl:
 

Ugg10

Distinguished Member
A very novel idea :thumbsup: - effectively putting lots of smaller ports in the big port.

I wonder if there's any research on this - from a theoretical viewpoint it would be a mathematical nightmare -probably need to book time on the world's biggest supercomputer. :rotfl:

From my little knowledge I think there are two effects at play here -

1) Assuming the straws are the same length as the original port then by adding the straws you are reducing the effective area by an amount (say 10-20%) by introducing the straw plastic walls therefore this will move the tuning frequency lower and so produce an output more like a sealed box than a bass reflex. However I think this is not the main factor.

2) The main factor I think is that the straws have a small cross section compare to the surface area of the straw wall and you will end up with a flow restriction due to boundary layer effects in each straw that is significantly bigger than the large original port i.e. for a specified flow rate the boundary layer on the port surface is of a set thickness (probably 1mm or less) which compared to the original port diameter is insignificant but applied to a 5mm straw it effective blocks around 25-50% of the straw area thereby significantly reducing the effective area of the port. You are effectively creating an aperiodic port or leaky box by adding the straws which is similar to using a porous foam bung (or loosely rolled up socks). For info the old Dynaco A25 speaker used an aperiodic port if you want to read up more (allows a smaller box than for a bass reflex but retains some of the lower bass content compared to a sealed box)

There are probably other physics at play but simplistically I think this is what is happening.
 

Helix Hifi

Well-known Member
@Ugg10, which sealed floor standing/stand mounted speakers up to Sonnetto 2, Dynaudio Evoke 20 price class can you recommend?

Aren’t sealed speakers better to use if you place close too the walls?
 

Baron Mole

Active Member
There are probably other physics at play but simplistically I think this is what is happening.
You've expressed in detail the vague thought in my head which was combination of area reduction and flow restriction through the straws "tuning" differently to the actual port. Hence my remark about maths nightmare.

"Other physics at play" Love the typically British understatement - in sound reproduction I'd like to know when there aren't ! :laugh:
 

Helix Hifi

Well-known Member
I’m no expert.

But if you place speakers with the bass port at rear of speakers, naturally the speakers we’ll not have enough air to breath. This resultant in muddy bass, depth etc. Of course Dali are one of the expiations. I believe this is because the wood fiber drivers are fast, not as heavy to move air.

If the speakers are designed with the bass port in the front of the speakers, then this problem is easier to deal with. But it depends even with front ported speakers. It all comes to the room, speaker design.

However sealed speakers don’t they produce deeper bass, not as slow as ported speakers? Also by taking advantage of cabinets them self, crossover settings, drivers, cabinets?

I still remember B&W famous “golf ball bass port”:D
 

ItsNotAllSnakeOil

Active Member
Very strange indeed. It should be the opposite. The longer away from the walls less bass boom you get. More focused midrange, treble. Depth also improves. Still again Dali tunes their speakers to be placed really close too the walls.

Break in is perhaps is the cause. Standing waves. How is the bass response if you stand in the room? Can you measure the sound with some software?
Yeah I’m going to experiment some more as I may be hearing things, or not hearing things. Could it be that they are so close to the wall that actually less air is getting pushed out and therefore less boom off the wall? Or is the boom generated inside the cabinet? My previous PSB Imagine speakers were rear ported and they did boom more when right up against the wall.
 

Helix Hifi

Well-known Member
Yeah I’m going to experiment some more as I may be hearing things, or not hearing things. Could it be that they are so close to the wall that actually less air is getting pushed out and therefore less boom off the wall? Or is the boom generated inside the cabinet? My previous PSB Imagine speakers were rear ported and they did boom more when right up against the wall.
It could be the walls are acting like ports pushing the bass towards the ports, in that way you are creating bass buffer of some kind.

Also as mentioned Dali tunes their speakers to be closed very close to the walls.

From my understanding rear ported, front ported speakers are designed the same way. To sum it up the port, drivers work together to produce deep punchy bass.

Sealed speakers are perhaps the best speakers to use if you are going to place them close to the walls. But limited in bass response, although faster from what I read online.

Take the Klipsch Heresy 4, that model is the first of the series to have the port placed on the front baffle of the speakers. The older models are sealed speakers if I’m not wrong.
 

FootHealer

Active Member
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FootHealer

Active Member
With regards to the issue being discussed, my Oberon 5s boom when too close to the front wall. I have a nasty room issue at around 50Hz which means too much bass and it gets really bloated and overshadows the rest of the music. I pulled the Oberon 5s about 1.5 feet from the wall and this was reduced massively.

The Oberon 1s interestingly are better close to the wall. I had them about 5cm from the wall in a desktop setup and the bass was great.

Interestingly, my Monitor Bronze 5s, which are front ported (but have a small rear port for the tweeter, I believe), do not excite my room at all and there is hardly any bump at 50Hz.

Sorry, this probably isn't helpful, but I guess what I'm saying is it might be a room issue, since people might get different results with Oberon 5s being close to the wall.
 

ItsNotAllSnakeOil

Active Member
With regards to the issue being discussed, my Oberon 5s boom when too close to the front wall. I have a nasty room issue at around 50Hz which means too much bass and it gets really bloated and overshadows the rest of the music. I pulled the Oberon 5s about 1.5 feet from the wall and this was reduced massively.

The Oberon 1s interestingly are better close to the wall. I had them about 5cm from the wall in a desktop setup and the bass was great.

Interestingly, my Monitor Bronze 5s, which are front ported (but have a small rear port for the tweeter, I believe), do not excite my room at all and there is hardly any bump at 50Hz.

Sorry, this probably isn't helpful, but I guess what I'm saying is it might be a room issue, since people might get different results with Oberon 5s being close to the wall.
Yeah, I've been experimenting with mine and moved them away from the wall and wider apart. I much prefer this, I didn't think they were booming that much before but was obviously wrong!
 

Helix Hifi

Well-known Member
Yeah, I've been experimenting with mine and moved them away from the wall and wider apart. I much prefer this, I didn't think they were booming that much before but was obviously wrong!
Do you use and kind of spikes, damping feet under the speakers? I use some kind of damping feet’s which couples the speakers from the floor, this results in fuller, precise bass response.
 
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ItsNotAllSnakeOil

Active Member
Do you use and kind of spikes, damping feet under the speakers? I use some kind of damping feet’s which couples the speakers from the floor, this results in fuller, precise bass response.
I used to have the spikes on but swapped them for the standard “rubber” feet. Not to go off topic but moving away from Tidal and on to Qobuz has also made improvements to my ears. None of that MQA nonesense.
 

Helix Hifi

Well-known Member
I used to have the spikes on but swapped them for the standard “rubber” feet. Not to go off topic but moving away from Tidal and on to Qobuz has also made improvements to my ears. None of that MQA nonesense.
If you men the rubber feet which are supplied by Dali, then I can tell you the adhesive tape we’ll fall out, or worn out, if you move the speakers around much. This is my experience with them.

I’ve ordered some spikes, they are arriving next week, hopefully there we’ll be an improvement.

But honest I can hear differences if I use spikes or not, the bass is more precise.
 

ItsNotAllSnakeOil

Active Member
If you men the rubber feet which are supplied by Dali, then I can tell you the adhesive tape we’ll fall out, or worn out, if you move the speakers around much. This is my experience with them.

I’ve ordered some spikes, they are arriving next week, hopefully there we’ll be an improvement.

But honest I can hear differences if I use spikes or not, the bass is more precise.
I do mean that yeah. I do have some spikes I can use if needed, and some little tests for them as I have a wooden floor. Might give them a try and see.
 

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