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So far I have only tried deploying my 4 in a center block 2 stacked on top of the other 2 with all mouths facing each other.  It worked great, nice wide and even dispersion out front with impressive rejection behind them.  I wish I would have measured dB in front vs behind but take my work for it they were much much  quieter behind the stack, which is super helpful keeping the energy off the stage.   Tomorrow I’ll be deploying them in a warehouse space, I plan to run them 4 side by side mouths on the ground, will update how it goes.  

I do want to experiment with left right stacks at some point, I have wondered how it would work 2 per side stacked in a tower with the vents coupled together.... meaning the vents would be coming out of the middle of the stack off the ground. I suspect they may not couple well with the ground plane like that... but it would make a convenient way to get my danleys up high without needing scaffolding.  Might not be best for bass music but maybe work good for house and techno, who knows.   Probably best just to build another pair to do 3 per side stacked on their sides haha. 

 

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Totally OT, but I listened to parts of the new Tool album "Fear Innoculum" with a friend today with generous volume.  The kick drums on this album really are phenomenal.  "Chocolate Chip Trip" is particularly noteworthy and seems like good demo/show-off material.  My only gripe is that it would have been better with no dynamics.  The limiter on the drums was a bit obvious at times.

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On 9/7/2019 at 1:27 PM, jay michael said:

So far I have only tried deploying my 4 in a center block 2 stacked on top of the other 2 with all mouths facing each other.  It worked great, nice wide and even dispersion out front with impressive rejection behind them.  I wish I would have measured dB in front vs behind but take my work for it they were much much  quieter behind the stack, which is super helpful keeping the energy off the stage.   Tomorrow I’ll be deploying them in a warehouse space, I plan to run them 4 side by side mouths on the ground, will update how it goes.  

I do want to experiment with left right stacks at some point, I have wondered how it would work 2 per side stacked in a tower with the vents coupled together.... meaning the vents would be coming out of the middle of the stack off the ground. I suspect they may not couple well with the ground plane like that... but it would make a convenient way to get my danleys up high without needing scaffolding.  Might not be best for bass music but maybe work good for house and techno, who knows.   Probably best just to build another pair to do 3 per side stacked on their sides haha. 

 

Thanks for the reply, I see a few pages back you also asked similar questions with not much reply. I think you are right though you should build another pair for 3 per side;-). Should of got the 8 ohm drivers ha? No just go 4 per side!..... hmm still not the right hieght;-/.... 6 per side>presto!

I have building a pair of these at the top of my to do list at present and am just working out my adjustments/deductions/add-ons for my cabinets hence the questions. What about the weight balance it looks pretty much 50 50 front/rear(im thinking about pole mount position for top box), was that your experience lifting them?

Also what about the hatch, I see its a little smaller than the othorn. Was there plenty of space getting the driver in and out as I intend to do that slightly differently requiring it to be a little smaller.

How'd this weekends show go?

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On 9/8/2019 at 11:55 AM, SME said:

Totally OT, but I listened to parts of the new Tool album "Fear Innoculum" with a friend today with generous volume.  The kick drums on this album really are phenomenal.  "Chocolate Chip Trip" is particularly noteworthy and seems like good demo/show-off material.  My only gripe is that it would have been better with no dynamics.  The limiter on the drums was a bit obvious at times.

Not a massive Tool fan, but I think I should give the record a spin. Had a listening session with my uncle lately and Pink Floyd's "Shine On You Crazy Diamond" just sounds so very clean and impactful. Now I couldn't help myself and had to turn it up again. Gotta say the fast kick drum on The Algorithm's "Trojans - Hard Mode" hits pretty hard. Celldweller's "Faction 14" is my go-to track for any system and it gives the subs some nice workout. SKHorn takes it like it's nothing thou 😎

Reducing the amount of compression/limiting would not be a good thing for 99% of the audio systems around. Most of the time people listen to music as background "filler", crazy dynamics might be pretty distracting, one might assume.

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On 9/8/2019 at 3:55 AM, SME said:

Totally OT, but I listened to parts of the new Tool album "Fear Innoculum" with a friend today with generous volume.  The kick drums on this album really are phenomenal.  "Chocolate Chip Trip" is particularly noteworthy and seems like good demo/show-off material.  My only gripe is that it would have been better with no dynamics.  The limiter on the drums was a bit obvious at times.

Agreed... Chocolate chip trip was the most exciting for me as well, it was literally a trip to experience :)   Very cool sound experience, felt like an amusement park ride.

 

7 hours ago, menace said:

Thanks for the reply, I see a few pages back you also asked similar questions with not much reply. I think you are right though you should build another pair for 3 per side;-). Should of got the 8 ohm drivers ha? No just go 4 per side!..... hmm still not the right hieght;-/.... 6 per side>presto!

I have building a pair of these at the top of my to do list at present and am just working out my adjustments/deductions/add-ons for my cabinets hence the questions. What about the weight balance it looks pretty much 50 50 front/rear(im thinking about pole mount position for top box), was that your experience lifting them?

Also what about the hatch, I see its a little smaller than the othorn. Was there plenty of space getting the driver in and out as I intend to do that slightly differently requiring it to be a little smaller.

How'd this weekends show go?

I could maybe justify the cost of building another pair simply to give more flexibility to set up arrangements... but so far the 4 have been giving me the horsepower needed for my needs, Ive yet to feel like I needed to run them up to limiting to get the output I needed.   They feel very balanced when carrying them, doable with 2 people but a 4 person carry is most desirable, it feels light and easily to maneuver with 4. 

The show on Saturday went well, client was impressed and has already indicated he wants to use the rig again.   It was a weird room, concrete industrial bay, cement walls with metal ceiling.  Only 20 feet wide, about 140 feet long with 50 foot ceilings.... basically a worst case scenario for good sound.....  I clustered the subs all upright vents on the bottom slightly off center in the room hoping to somewhat reduce low frequency cancellations down the length of the room.  It mostly worked, with the room empty walking front to back bass energy did rise and fall a couple times over the length of the room... but once the room got packed (was a humid sweaty mess) it evened out nicely.  I ran the Danley's upright in 40 degree horizontal mode which worked awesome keeping sound off the walls, also tilted them downwards enough to keep sound off the metal roof.  Bass music all night, low sub frequencies sounded full and clean, mids and highs were impressive considering the room.  I did feel like it lacked some kick definition up the middle however, close to the walls the kick energy felt great, but up the sweet spot in the middle of the room it felt a bit lacking... not sure if this was room related or if the upright vents on the bottom configuration contributed to it. Considering the music styles, It wasn't really an issue, I don't think anybody other than me (worst self critic) would have noticed.  Next time ill try double stacked vents in the middle, or possibly coupling all the subs on one wall.  Considering the venue is only 20 feet wide, I think all 4 subs stacked with vents against the wall might actually work the best in such a narrow long room... should at least minimize cancellations. 

As mentioned I never felt the need to run it up to my limiting which was set at 44 volts.  I certainly did have heat in the back of mind as the room got terribly hot and humid.  They sounded rowdy and clean, never distressed and could not feel any discernible temperature on the cabinets.  I did have to move a handful of people away from sitting up against the vents... it seemed people were really enjoying ride the skrams were putting out :) 

2 hours ago, peniku8 said:

Not a massive Tool fan, but I think I should give the record a spin. Had a listening session with my uncle lately and Pink Floyd's "Shine On You Crazy Diamond" just sounds so very clean and impactful. Now I couldn't help myself and had to turn it up again. Gotta say the fast kick drum on The Algorithm's "Trojans - Hard Mode" hits pretty hard. Celldweller's "Faction 14" is my go-to track for any system and it gives the subs some nice workout. SKHorn takes it like it's nothing thou 😎

Reducing the amount of compression/limiting would not be a good thing for 99% of the audio systems around. Most of the time people listen to music as background "filler", crazy dynamics might be pretty distracting, one might assume.

Def worth a listen regardless if your a fan or not.  Simply from a production and sound design level its a treat for your ears.

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6 hours ago, jay michael said:

The show on Saturday went well, client was impressed and has already indicated he wants to use the rig again.   It was a weird room, concrete industrial bay, cement walls with metal ceiling.  Only 20 feet wide, about 140 feet long with 50 foot ceilings.... basically a worst case scenario for good sound.....  I clustered the subs all upright vents on the bottom slightly off center in the room hoping to somewhat reduce low frequency cancellations down the length of the room.  It mostly worked, with the room empty walking front to back bass energy did rise and fall a couple times over the length of the room... but once the room got packed (was a humid sweaty mess) it evened out nicely.  I ran the Danley's upright in 40 degree horizontal mode which worked awesome keeping sound off the walls, also tilted them downwards enough to keep sound off the metal roof.  Bass music all night, low sub frequencies sounded full and clean, mids and highs were impressive considering the room.  I did feel like it lacked some kick definition up the middle however, close to the walls the kick energy felt great, but up the sweet spot in the middle of the room it felt a bit lacking... not sure if this was room related or if the upright vents on the bottom configuration contributed to it. Considering the music styles, It wasn't really an issue, I don't think anybody other than me (worst self critic) would have noticed.  Next time ill try double stacked vents in the middle, or possibly coupling all the subs on one wall.  Considering the venue is only 20 feet wide, I think all 4 subs stacked with vents against the wall might actually work the best in such a narrow long room... should at least minimize cancellations.

In a room that narrow, you might be able to get away with spreading the Skrams out evenly across the width of the room with "half-spacing" between the Skrams on the sides and the side-walls.  Visualize each side-wall as a mirror, and then you can "see" that this effectively creates a very wide virtual horizontal line array.  It'll likely work even better with 6 Skrams because of the tighter spacing.  Ideally, you want spacing to be less than 1/4 wavelength (tighter still is even better).  For Skrams set 5 feet apart, the 1/4 wavelength is around 57 Hz.  (Simple formula: wavelength equals 1136 ft/sec divided by frequency; then divide *that* by 4 to get the 1/4 length.)  If set 3.3 feet apart the 1/4 wave is at around 85 Hz.  Nice!

6 hours ago, jay michael said:

As mentioned I never felt the need to run it up to my limiting which was set at 44 volts.  I certainly did have heat in the back of mind as the room got terribly hot and humid.  They sounded rowdy and clean, never distressed and could not feel any discernible temperature on the cabinets.  I did have to move a handful of people away from sitting up against the vents... it seemed people were really enjoying ride the skrams were putting out :)

This is a big reason why it's very good to be over-provisioned.  Recall that every +3 dB increase involves *doubling* of power and dissipated heat.  Likewise, every +10 dB involves *10 times* the power and dissipated heat.

I just love the mental image of the Skrams drawing people in like moths to a light, causing them to swoon in front of them.  :lol:

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1 hour ago, SME said:

In a room that narrow, you might be able to get away with spreading the Skrams out evenly across the width of the room with "half-spacing" between the Skrams on the sides and the side-walls.  Visualize each side-wall as a mirror, and then you can "see" that this effectively creates a very wide virtual horizontal line array.  It'll likely work even better with 6 Skrams because of the tighter spacing.  Ideally, you want spacing to be less than 1/4 wavelength (tighter still is even better).  For Skrams set 5 feet apart, the 1/4 wavelength is around 57 Hz.  (Simple formula: wavelength equals 1136 ft/sec divided by frequency; then divide *that* by 4 to get the 1/4 length.)  If set 3.3 feet apart the 1/4 wave is at around 85 Hz.  Nice!

This is a big reason why it's very good to be over-provisioned.  Recall that every +3 dB increase involves *doubling* of power and dissipated heat.  Likewise, every +10 dB involves *10 times* the power and dissipated heat.

I just love the mental image of the Skrams drawing people in like moths to a light, causing them to swoon in front of them.  :lol:

Thanks for the formula, I had read an article by Nathan lively that described this but his formula was a bit different, allowed even wider spacing.  When you say 3.3 feet apart that should be center to center yeah?  Or 3.3 feet between cabinets?  And what frequency would you use in the formula? The crossover frequency?  I guess you would want them tight enough so that any frequency produced by the subs would fall within 1/4 wavelength of each other?

And yeah, better to have more than enough horsepower on tap, I would rather run them conservatively vs full tilt all night.  Ill have to keep my eyes on driver prices, perhaps after some more rental revenue ill try and pick up another pair. 

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Excellent questions!  My formula is for center-to-center spacing and it assumes point sources.  The cabinets do radiate over a width, which can help but doesn't make much difference until they get pretty close together.

Otherwise, I think you have the right idea.  The 1/4 wavelength is really a fuzzy rule-of-thumb.  What you *really want to avoid* is playing frequencies whose 1/2 wavelength is the distance between centers.  Then the subs will be literally fighting one another.  :(

I swear, no matter how much we encourage newbies on this site to go bigger than they think they'll want, they practically always start talking about "adding more" soon after their first DIY project is complete.  It really is a long running joke in the world of DIY subs.  :D

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6 hours ago, SME said:

Excellent questions!  My formula is for center-to-center spacing and it assumes point sources.  The cabinets do radiate over a width, which can help but doesn't make much difference until they get pretty close together.

Otherwise, I think you have the right idea.  The 1/4 wavelength is really a fuzzy rule-of-thumb.  What you *really want to avoid* is playing frequencies whose 1/2 wavelength is the distance between centers.  Then the subs will be literally fighting one another.  :(

I swear, no matter how much we encourage newbies on this site to go bigger than they think they'll want, they practically always start talking about "adding more" soon after their first DIY project is complete.  It really is a long running joke in the world of DIY subs.  :D

There is a nice paper by Electro Voice on different sub arrays and their dispersion patterns. Correct delays are the key for larger events. Controlling noise pollution is also a big topic for open air events. Beam forming also helps achieving a more even coverage. Many examples are impractical space-wise, but I liked the V setup.

On the DIY side, I never felt like adding a second SKHorn to my HT :P 

Was planning on building two SKRams for my live setup, since the SB18 are not always available, but I'll likely just go with my own design. It's smaller and I really wanna see how it performs.

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11 hours ago, SME said:

Excellent questions!  My formula is for center-to-center spacing and it assumes point sources.  The cabinets do radiate over a width, which can help but doesn't make much difference until they get pretty close together.

Otherwise, I think you have the right idea.  The 1/4 wavelength is really a fuzzy rule-of-thumb.  What you *really want to avoid* is playing frequencies whose 1/2 wavelength is the distance between centers.  Then the subs will be literally fighting one another.  :(

I swear, no matter how much we encourage newbies on this site to go bigger than they think they'll want, they practically always start talking about "adding more" soon after their first DIY project is complete.  It really is a long running joke in the world of DIY subs.  :D

Ok great! Updated my notes :)  One last question on the spacing.  By keeping the subs within 1/4 wave length of each other within their operating freq range,  that will ensure no destructive cancellations.... but will it effect the subs ability to couple to each other? Will you loose some output gained by having all of the subs side by side? 

I think there is a bit of a trap that you can fall into with how many cabinets you really need to fill a space.  When I assembled by first system I started with a pair of my old RCF 4pro subs under a pair of the RCF towers.  Pretty much right away I knew I was going to need more, so I added another pair of subs.  The jump between 2 to 4 subs was a substantial improvement.  Maybe a year after I added another pair but that time it didn't feel like such a big jump forward.... I eventually added another pair and ran it like that for pretty much a decade.  

The interesting thing was occasionally when I deployed only 6 or even 4 subs.... it really didn't feel like I was missing that much power.  Obviously there is a point where you need more power to cover larger spaces and larger crowds but you should strongly consider really what your needs are before selling your house to afford more speaker cabinets haha. Not running your gear at full tilt is also a consideration for sure.    On the flip side, the other thing I come across, especially in my city is that often crews bring literally too many cabinets into venues that just don't need that much gear.   There is a point where I believe too much gear will have a negative effect over the listening experience.  Yeah it certainly blurs your vision and re-arranges your guts,  but if the low frequency pressure is so high that it literally overloads yours ears ability to discern what the rest of the music sounds like I really don't see the point.  I suppose maybe some people simply want a visceral physical experience like that,  but I think more people really want to experience the full range experience of the music artist they came to hear.  For the venue sizes we use, I can't really think ill be left wanting with what my 4 skrams can put out..... maybe 6 just to get off the gas pedal a bit... but 8 would simply be overkill.

4 hours ago, peniku8 said:

There is a nice paper by Electro Voice on different sub arrays and their dispersion patterns. Correct delays are the key for larger events. Controlling noise pollution is also a big topic for open air events. Beam forming also helps achieving a more even coverage. Many examples are impractical space-wise, but I liked the V setup.

On the DIY side, I never felt like adding a second SKHorn to my HT :P

Was planning on building two SKRams for my live setup, since the SB18 are not always available, but I'll likely just go with my own design. It's smaller and I really wanna see how it performs.

I've got that paper bookmarked, there really is some good info in there.  I used to get a fairly narrow hot spot out the front of my 8 old subs.  Splaying them in a arc really helped even out the coverage out front... such a simple way to improve the directionality of a sub array     

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3 hours ago, jay michael said:

Ok great! Updated my notes :)  One last question on the spacing.  By keeping the subs within 1/4 wave length of each other within their operating freq range,  that will ensure no destructive cancellations.... but will it effect the subs ability to couple to each other? Will you loose some output gained by having all of the subs side by side?

Yes, but at 1/4 wavelength the loss will be pretty modest.  And here again is a reason to have extra headroom to work with.

3 hours ago, jay michael said:

The interesting thing was occasionally when I deployed only 6 or even 4 subs.... it really didn't feel like I was missing that much power.  Obviously there is a point where you need more power to cover larger spaces and larger crowds but you should strongly consider really what your needs are before selling your house to afford more speaker cabinets haha. Not running your gear at full tilt is also a consideration for sure.    On the flip side, the other thing I come across, especially in my city is that often crews bring literally too many cabinets into venues that just don't need that much gear.   There is a point where I believe too much gear will have a negative effect over the listening experience.  Yeah it certainly blurs your vision and re-arranges your guts,  but if the low frequency pressure is so high that it literally overloads yours ears ability to discern what the rest of the music sounds like I really don't see the point.  I suppose maybe some people simply want a visceral physical experience like that,  but I think more people really want to experience the full range experience of the music artist they came to hear.  For the venue sizes we use, I can't really think ill be left wanting with what my 4 skrams can put out..... maybe 6 just to get off the gas pedal a bit... but 8 would simply be overkill.

For your situation, it sounds like 4 Skrams is plenty for output.  Where 6 or 8 would come in handy is the increased placement flexibility and potential for sound-field control.  Though I guess you have to decide whether it's worth hauling extra gear for each different situation.  That's the real downside to having more gear than you need.  Once it's setup, you can always turn the gains down on larger numbers of subs.

And I agree that there's a lot more to good bass than sheer quantity.  People routinely assume that high SPL is required for visceral impact, but that's not the case at all, especially if high quality is the goal.    As far as I can tell, one can experience tactile sensations from bass that's barely above hearing threshold.  The answer to the question of whether one can "feel the bass" depends more on the quality of information received by the brain than the SPL.  Sure, one can always induce sensation given enough brute force, but I believe it's also possible to have sensations that are tight, rich, and detailed, and that you can still feel (albeit more subtly and with less "bottom") at low listening levels.  We experienced as much in here with the Tool album, in which the rolling kick-drum sensations were still there at a "background level".

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You can also reach the effect of having more tactile sensation than one might suggest by the volume by having a wooden floor. So Far I've been in two venues with a wooden riser for either FOH or a very small stage and both increased the tactile sensation manifold compared to the tarmac floor. You're also fooled to percieve a higher volume. 

The second occasion where I noticed this has to do with room cancelations; in our studio to be precise. We have a small dip around 63Hz and another dip at 75Hz, which I EQ'd out. Now the FR itself is pretty flat but you feel an increased tactile sensation from these frequencies. That's a bad thing for the studio environment :(

I've already isolated the sub from the ground mechanically, so it's pure acoustic tactility.

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13 minutes ago, peniku8 said:

The second occasion where I noticed this has to do with room cancelations; in our studio to be precise. We have a small dip around 63Hz and another dip at 75Hz, which I EQ'd out. Now the FR itself is pretty flat but you feel an increased tactile sensation from these frequencies. That's a bad thing for the studio environment :(

I've already isolated the sub from the ground mechanically, so it's pure acoustic tactility.

I suggest turning off that EQ.  Such dips are often caused by localized interference effects which listeners should largely be able to hear through.  For me, those frequencies are felt at least as much as they are heard when they occur in complex music, so if you are feeling more sensation at those frequencies, it probably means you've got peaks there.

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16 minutes ago, SME said:

I suggest turning off that EQ.  Such dips are often caused by localized interference effects which listeners should largely be able to hear through.  For me, those frequencies are felt at least as much as they are heard when they occur in complex music, so if you are feeling more sensation at those frequencies, it probably means you've got peaks there.

Judging the audible aspect only, the EQ sounds 'right' thou. The room is lacking in these regions or let's say it has got way too much in others. We already had a discussion about the studio space already thou and I kinda decided to leave it as is until I change out the subs entirely. A non-ideal sound reproduction is not good, but a constantly changing one is even worse in a studio.

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17 hours ago, Droogne said:

Great to know the hornresp parameters for the Skram with all vents, but how would I convert this to a configuration with only 1 vent open? 

Anyone who can help?

There are 4 ports when all are open= Divide the Ap (port area) of 725.76cm2 / 4 = Each port has an area of 181.44cm. Multiply 181.44 by the number of ports that are open and input into Ap.

Also some volume from the vent is added back into the enclosure when blocked. Add 14.42L to the enclosure rear chamber volume (Vrc) for each port that is closed off.

3 port operation = an Ap of 544.32 and a Vrc of 216.15

2 port operation = Ap of 362.88 and a Vrc of 230.57

1 port operation = Ap of 181.44 and a Vrc of 245

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Hey Josh, what would happen if you blocked a port internally where the port starts?  I personally don't need or feel the need to play with the tuning on mine but when I was constructing mine I thought to myself it might be easier to add the blockage internally where the vent port starts... It would also look nicer than doing it externally

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1 hour ago, Ricci said:

There are 4 ports when all are open= Divide the Ap (port area) of 725.76cm2 / 4 = Each port has an area of 181.44cm. Multiply 181.44 by the number of ports that are open and input into Ap.

Also some volume from the vent is added back into the enclosure when blocked. Add 14.42L to the enclosure rear chamber volume (Vrc) for each port that is closed off.

3 port operation = an Ap of 544.32 and a Vrc of 216.15

2 port operation = Ap of 362.88 and a Vrc of 230.57

1 port operation = Ap of 181.44 and a Vrc of 245

Ok thanks. I modelled them all out for my own reference. Here the results for everyone interested. I Xmax limited the output (15mm for the 21Sw152)

1 port operation. Xmax at ~22hz, 60 volts

image.png.46a95a99f59173c44bd1a46e164a9788.png

2 port operation. Xmax at 30hz, 70 volts

image.png.cdaee8d04fa968283d560d3f3c8ac0a0.png

3 port operation. Xmax at ~22hz, 80 volts

image.png.540f0715e36509f990b262428f408777.png

 

 

 

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20 hours ago, jay michael said:

Hey Josh, what would happen if you blocked a port internally where the port starts?  I personally don't need or feel the need to play with the tuning on mine but when I was constructing mine I thought to myself it might be easier to add the blockage internally where the vent port starts... It would also look nicer than doing it externally

Doing so wastes space. It lowers the back chamber volume which raises the tuning (ever so) slightly and decreases bottom end output. Probably by less than half a db but it's still wasted potential.

Look here if you wanna get some ideas for port block solutions.

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