As has been noted, Troels is wrong about 'midrange leakage' unless he's working with a different form of physics the rest of us are obliged to live with, although excess air velocity can cause problems (not in this case given the duct CSA), as can the resonant modes of the duct itself (not impossible in this case & may be what he's apparently wary about).
You seem to have asked for advice, received it and made your mind up, so I'm not sure there's much left to say on the matter other than 'good luck'.
You seem to have asked for advice, received it and made your mind up, so I'm not sure there's much left to say on the matter other than 'good luck'.
Yeah that is best advice for now.
colmo, better prepare yourself with for some kind of prototyping possibility as you plan to deviate from the provided plan. Luckily the plan contains port with an elbow which will allow you to scan good inlet position for the port in case there is this midrange leakage. Just build it from material that is easily / cheaply altered like plumbing stock, some kind of opening somewhere so that you can adjust the port after the box is put together. Heck, there is chance changed port position gives less mid leakage than Troels proposed one. I guess Troels has found that placement good enough so it would be easiest to stick with it.
Worst case you spend time and money for nice enclosure just to find out the port detracts from the experience, quick fast prototype will prevent this happening.
colmo, better prepare yourself with for some kind of prototyping possibility as you plan to deviate from the provided plan. Luckily the plan contains port with an elbow which will allow you to scan good inlet position for the port in case there is this midrange leakage. Just build it from material that is easily / cheaply altered like plumbing stock, some kind of opening somewhere so that you can adjust the port after the box is put together. Heck, there is chance changed port position gives less mid leakage than Troels proposed one. I guess Troels has found that placement good enough so it would be easiest to stick with it.
Worst case you spend time and money for nice enclosure just to find out the port detracts from the experience, quick fast prototype will prevent this happening.
But on his site he specifically said "You can place the port to the front or to the rear to your liking."
I bet he just built the pictured speakers with the port on the rear, so doesn't really knows if bottom is just better than front or not (even if he suggests both rear and front).
If the kit contains the elbow port, then place it at the front.
You miss the point. The bigger problem in placing a speaker against the wall is dips and peaks in the midrange. This is a severely compromised placement, and fearing about an hypothetically midrange leakage from a front port doesn't make much sense.
Ralf
Ok see hat you mean Ralf regarding midrange.
As a matter of interest Troels suggests that either bottom outlet or keeping the port on the rear even though there is only a 2 inch gap is best.
As a matter of interest Troels suggests that either bottom outlet or keeping the port on the rear even though there is only a 2 inch gap is best.
Flip a coin!
Either way leave a gap = vent effective radius*0.613 to ensure good boundary loading.
Either way leave a gap = vent effective radius*0.613 to ensure good boundary loading.
If I want to try a "bottom" port (kind of like this subwoofer), how tall should the feet be? What are its upsides and downsides?
In this article it says that
In this article it says that
but how can be a surface so big be an extension of the port?
Just my 2ct. For a box with a full range driver - never have the BR on the front if 1.) It ain't an aperiodic Box , 2.) It's only one simple pipe instead of higher resistance slots, 3.) The back could be an option.
Depending on how far away you sit from the speaker a part the unwanted midrange frequencies could be hearable from a large opening in the front. The better the box design and BR design the lesser the trouble.
With an opening to the back an too close to the wall it's nearly the same as putting it on the bottom. Somehow it sounds more "full" bass enhanced but also not nice - smeared. Putting the opening to the bottom forces you to elevate the speaker to the next reflecting surface or else it's like an extension to your BR or depending on the size of the BR maybe a n additional resistance.
If you have time for further experiments you can find the right length for this approach and it ain't the first design using it.
Depending on how far away you sit from the speaker a part the unwanted midrange frequencies could be hearable from a large opening in the front. The better the box design and BR design the lesser the trouble.
With an opening to the back an too close to the wall it's nearly the same as putting it on the bottom. Somehow it sounds more "full" bass enhanced but also not nice - smeared. Putting the opening to the bottom forces you to elevate the speaker to the next reflecting surface or else it's like an extension to your BR or depending on the size of the BR maybe a n additional resistance.
If you have time for further experiments you can find the right length for this approach and it ain't the first design using it.
Thank you.
Yes I'm planning to make a fullrange speaker.
My choice is either placing a smaller port on the side (or the back but then might be too close to the wall), or a bigger port on the bottom that is the only place it could fit length wise. I guess if I want to chose the latter I need to introduce some port losses to avoid "boom". Maybe even shorten the pipe because it will tune lower than expected.
If I choose the former, the port velocity becomes very high at high volumes.
But what do you mean with "elevating the speaker to the next reflecting surface"? I can't quite wrap my head around it.
Yes I'm planning to make a fullrange speaker.
My choice is either placing a smaller port on the side (or the back but then might be too close to the wall), or a bigger port on the bottom that is the only place it could fit length wise. I guess if I want to chose the latter I need to introduce some port losses to avoid "boom". Maybe even shorten the pipe because it will tune lower than expected.
If I choose the former, the port velocity becomes very high at high volumes.
But what do you mean with "elevating the speaker to the next reflecting surface"? I can't quite wrap my head around it.
