Don’t let your ears fool you. Why would better internal damping worsen transient response if I might ask? Probably missing the ringing of the former situation?
Perhaps it is 'ringing' that is absent, I am not sure. I will play around a little and see if a 'better' solution is there but it feels a little overdamped.
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Am I correct in assuming that as mid and higher frequencies radiate more direct, much of these are directed at the near sidewalls first as the magnet structure itself is in the way?
Would it not make sense to tackle these there?
Would it not make sense to tackle these there?
Some model of Harbeth loudspeakers are almost full foam inside. Bass reflex loads.
Bitumed pads add weigth but also make lower rhe panels vibrations, which is not wanted. It may or not be heard.
The volume of the cabinet can be changed by the foam and insulation as well... the ports are also tunned relative to that volume. It is maybe what you hear more than standing waves behavior inside the cabinet...
You also can experiment with ports stuffing... and loudspeakers room placement and toe-in/off.
Cheers.
Bitumed pads add weigth but also make lower rhe panels vibrations, which is not wanted. It may or not be heard.
The volume of the cabinet can be changed by the foam and insulation as well... the ports are also tunned relative to that volume. It is maybe what you hear more than standing waves behavior inside the cabinet...
You also can experiment with ports stuffing... and loudspeakers room placement and toe-in/off.
Cheers.
Get some measurement stuff and check for it by distilling burst decay plots from close range measurements of the woofer. And: you didn’t try to answer my question 😉
Sound propagation hardly isn’t ray tracing at the frequencies involved (<3kHz). Don’t think of it that way.
I’ve changed the configuration of damping; I halfed the size of the pad direct behind the driver leaving space to either side. Added ‘miracle’ sponge (melanine foam?) to either side of the driver.
The result is similar to before adding any damping/stock insofar that lifeliness has been restored at cost to a slight ‘boxyness’.
I guess the melanine foam pads don't do much as a/ they are attached to the walls rather than in free space and b/they are to thin to be effective.
Onwards to find an in between solution 😀.
PS, I couldn't get the double sided tape to stick to the melanine foam so tried to superglue them in. No joy. So I added superglue to the foam and put the tape over it. I noticed whilst pressing the tape down that it got very hot … ! The fumes eminating afterwards were something to behold but now they stick 😎👍🏿
The result is similar to before adding any damping/stock insofar that lifeliness has been restored at cost to a slight ‘boxyness’.
I guess the melanine foam pads don't do much as a/ they are attached to the walls rather than in free space and b/they are to thin to be effective.
Onwards to find an in between solution 😀.
PS, I couldn't get the double sided tape to stick to the melanine foam so tried to superglue them in. No joy. So I added superglue to the foam and put the tape over it. I noticed whilst pressing the tape down that it got very hot … ! The fumes eminating afterwards were something to behold but now they stick 😎👍🏿
To be honest, I would consider stuffing is used to try and cure a problem rather than solve it; a tapering wedge, even if folded, works much better than stuffing a box. I wonder if blu-tacking in some thin wood or cardboard panels inside might be worth playing around with.
I'd still use loose stuffing to increase the effective volume though. This is yet anouther advantage of a WAW design, you can heavily stuff the bass chamber, but leave the full range chamber empty, so it dosen't deaden the mids.
I'd still use loose stuffing to increase the effective volume though. This is yet anouther advantage of a WAW design, you can heavily stuff the bass chamber, but leave the full range chamber empty, so it dosen't deaden the mids.
If it's a vented design that will also reduce or stop the port output (low end) ...
I would not do that. Midrange is where enclosure reflections will affect the sound (and frequency response) so you do want to absorb all back radiated sound.
The speaker in question is Mission 752, a 2-way speaker is very problematic, trying to get decent bass and clean mids at the same time, same driver and enclosure...
Floorstanding with 6,5" aerogel woofer, 3,6kHz xo. Very popular and highly rated at it's time
https://www.yumpu.com/fr/document/read/47730253/mission-752-freedom-loudspeaker-dutchaudioclassicsnl
https://pinkfishmedia.net/forum/threads/mission-752-measurements.215402/
I wouldn't break the box, just play with stuffing and start looking for 3-way towers! Retail value is still quite good
Floorstanding with 6,5" aerogel woofer, 3,6kHz xo. Very popular and highly rated at it's time
https://www.yumpu.com/fr/document/read/47730253/mission-752-freedom-loudspeaker-dutchaudioclassicsnl
https://pinkfishmedia.net/forum/threads/mission-752-measurements.215402/
I wouldn't break the box, just play with stuffing and start looking for 3-way towers! Retail value is still quite good
Thank you Juhazi. I have absolutely no issues with the bass in my room. It goes down well below its rated 40hz with in-room help and sounds lovely delineated yet powerful for a two way of modest dimensions. No one note.
I am probably over emphasizing the 'problem' with boxiness. It is (very) slight and my previous 'stuffing' (see earlier in the thread) completely got rid of that but at expense of some, lets call it 'liveliness'.
As I said, these replaced some very highly rated Stirling speakers and I much prefer these. Once I find the compromise I will be happy 😎
Of course, there is always a better speaker out there but for the moment, this will do.
I am probably over emphasizing the 'problem' with boxiness. It is (very) slight and my previous 'stuffing' (see earlier in the thread) completely got rid of that but at expense of some, lets call it 'liveliness'.
As I said, these replaced some very highly rated Stirling speakers and I much prefer these. Once I find the compromise I will be happy 😎
Of course, there is always a better speaker out there but for the moment, this will do.
Well, it continuous (my by ear tuning attempts); Having added the additional foam the top enclosure now excites a (very) strong mode. Further underlined by quite some resonance through the front 3 ports. Putting my hand over the ports I can feel all 3 resonating/vibrating.
I guess (!) the added foam has increased the top cabinet enclosure. The outcome ... not good. I will remove some of the foam and just leave one piece mid cabinet behind the driver. That seemed to have been the best compromise.
I may continue after this with some front port obstruction and see what the outcome of that is. Far easier to do than continuously taking the drivers out too.
It just resonated with me that another manufacturer using minimal or no damping is Totem. Sometimes less is more.
I guess (!) the added foam has increased the top cabinet enclosure. The outcome ... not good. I will remove some of the foam and just leave one piece mid cabinet behind the driver. That seemed to have been the best compromise.
I may continue after this with some front port obstruction and see what the outcome of that is. Far easier to do than continuously taking the drivers out too.
It just resonated with me that another manufacturer using minimal or no damping is Totem. Sometimes less is more.
Don’t believe manufacturers on their words.
What is wrong with resonating ports? That is the general idea of them…
What is wrong with resonating ports? That is the general idea of them…
Not that strongly. It literally is one mode, very strong that was not there before. The change of volume/foam has clearly excited the enclosure, not in a particular enjoyable way I may add.
I won’t say it’s not true, but think it’s unlikely that absorbing stuff causes resonances. The only possibility I see is that a standing wave has changed due to the damping and somehow its velocity node ended up at the port end inside. But without measurements it’s just guessing.