S-Man
StrivingON
Strange then that the LS50 is supplied with foam bungs and that the designers of the LS50 had no reservations whatsoever when we blocked the ports to demo them with our bass extension system (which eventually spawned the KC62).
Loudspeakers That Do It All
- Thread starter ryder
- Start date
Strange then that the LS50 is supplied with foam bungs and that the designers of the LS50 had no reservations whatsoever when we blocked the ports to demo them with our bass extension system (which eventually spawned the KC62).
S-Man
StrivingON
Only if you like listening to port leakage - see fig 3:
https://www.stereophile.com/content/kef-ls50-anniversary-model-loudspeaker-measurements
Here are my (in-room) measurements of LS50 with and without a plug:
Please point out the difference in the lower midrange.
windhoek
The Phoolosopher
As I mentioned in another thread, I've replaced the bungs that came with my Tannoys with these fish tank filters (as originally proposed by Mike42) as the filters are more aerated than the supplied bungs, which allows for a more natural effect that using the supplied bungs, especially when the bungs are pushed in fully. I tried having the bungs that came with my speakers all the way in but it just didn't sound right at all. Thankfully, the fish tank filters can deliver the effect I want/need but without skewing the end sound, or at least, not skewing anywhere near as much as the supplied bungs do when they're pushed in all the way. Fwiw, I'm currently using 3 filters per port and it sounds good.
This site contains affiliate links for which pink fish media may be compensated.
Fatmarley
"It appears my intelligence circuits have melted"
Only if you like listening to port leakage - see fig 3:
https://www.stereophile.com/content/kef-ls50-anniversary-model-loudspeaker-measurements
Here are my (in-room) measurements of LS50 with and without a plug:
Please point out the difference in the lower midrange.
Depends on where you consider low mids to start. The lowest recorded is 0.189hz. I just googled "Male vocal range in Hertz" and this is the first thing that came up - "The voiced speech of a typical adult male will have a fundamental frequency from 85 to 155 Hz"
In your measurement, you can clearly see the port has influence down to about 160hz.
S-Man
StrivingON
What I can very clearly see, when I zoom in on the chart, is that the port only has an effect >1dB below 126Hz.
Lower midrange is 250Hz - 500Hz according to this, that's one to two octaves higher:
https://www.teachmeaudio.com/mixing/techniques/audio-spectrum
Fatmarley
"It appears my intelligence circuits have melted"
Let's put it another way. There's no mechanism other than frequency response that would affect the midrange, so if the midrange is degraded when a port is plugged, it's purely down to the frequency response.
Drivers designed for ported enclosures have stronger motors than ones designed for sealed, so when you put it in a sealed box, it's going to have less trouble fighting against the air pressure than a driver that's actually designed for sealed enclosures.
Drivers designed for ported enclosures have stronger motors than ones designed for sealed, so when you put it in a sealed box, it's going to have less trouble fighting against the air pressure than a driver that's actually designed for sealed enclosures.
Fatmarley
"It appears my intelligence circuits have melted"
Like I said above, a speaker designed for a ported enclosure will have a more powerful motor compared to one designed for a sealed box. A driver designed for a sealed box has a weaker motor and often floppy suspension. If that was the case, sealed box speakers would all have a bad midrange.
I know what it sounds like to seal a port, I've done it a number of times, and it can ruin the midrange, but it's nothing other than the frequency response.
MrChad
Well-Known Member
I have recommended Monitor Audio GR60 to many friends over the years who ask advise on getting a "good system". Another was the Revolver R33, both I feel are easy speakers to live with, that do many things very well.
At least for those of us not box swapping searching for the ever elusive perfection. But both good all round speakers, with the proviso, they are considerately positioned in an appropriately damped room.
They like most speakers above a certain price point are not conducive to laminate flooring and empty rooms. Yet sound absorption in rooms is more often than not totally neglected, it rarely gets a look in, while the lower and lower mid frequency's bounce off every surface causing a chaotic sound the owner of tolerates, unaware the problem and no amount of box swapping will ever sort out room reflections.
At least for those of us not box swapping searching for the ever elusive perfection. But both good all round speakers, with the proviso, they are considerately positioned in an appropriately damped room.
They like most speakers above a certain price point are not conducive to laminate flooring and empty rooms. Yet sound absorption in rooms is more often than not totally neglected, it rarely gets a look in, while the lower and lower mid frequency's bounce off every surface causing a chaotic sound the owner of tolerates, unaware the problem and no amount of box swapping will ever sort out room reflections.
cooky1257
pfm Member
The LS50 is tightly tuned to 52hz, this means that either side of that tuning, port output gets progressively more out of phase with the direct driver output. If the port has significant out of band output at low mid frequencies then there will be some response impact due to cancelation. Blocking the port will of course remove those effects but simultaneously load the driver differently and change/increase the box F3 point and potentially given the size of the LS50 this may be quite high and impact the low mids as the output rolls off.
S-Man
StrivingON
Based on my LS50 measurements which shows almost no effect on the frequency response, it seems most likely that b) from post #118 is the reason.
I am actively filtering at 120Hz and crossing over to bass extenders which re-balances the effect of the blocked port. The benefits are:
Accurate extended bass instead of limited bass with timing issues.
Reduced excursions of the bass/mid driver which reduces distortion.
Higher SPL potential (if that matters?).
Easier load on the amp driving the LS50s .
I have tried lots of ported and sealed box speakers with this system and they are all significanty improved throughout the frequency range. Even Gale 401s sound a bit tubby and ploddy compared to with the bass extenders.
Funnily enough the speakers we tried with the extenders, which showed the least improvement in sound quality, were Quad 989s. Unlike most box speakers they don't seem to produce bass overhang (when correctly positioned in a sympathetic room) that masks musical information.
So, trying to get back on topic - any speaker that "does it all" needs to have bass with accurate transient response. There are not many that can do this.
CTank
pfm Member
Revolver R33’s seem to have been unfairly forgotten. Easy to drive (I used Sugden and a 300b valve amp with good results), good with all music, and free of any audible nasties. You could certainly do a lot worse.
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Hazelberry
sister
Except for the early Wharfedale Diamonds, I’ve always found ported speakers a real battle & have come to avoid them like the plague.
The best way I’ve found to reduce bass in ported speakers is to lengthen the port. I’ve used rolled cardboard. Just an extra 5mm can make all the difference. Midrange & dynamics are unaffected.
The best way I’ve found to reduce bass in ported speakers is to lengthen the port. I’ve used rolled cardboard. Just an extra 5mm can make all the difference. Midrange & dynamics are unaffected.
The reference to the ATC SCM100ASL speakers brought back some special memories to me. Many years ago (probably late nineties) I met a chap at a social event who ran a Naim NAC52 running into a pair of ATC SCM100ASLs whilst I was running a Naim 52/NAP300 set up into a pair of Briks on a Mana stand. He was thinking of buying my system and I sort of fancied his, so one Saturday morning I took my Briks and NAP300 to his place and his ATC SCM100ASLs came back to mine. His speakers were active and did not need a power amp.
The deal was that we would use each others speakers for a month and we could pop over to each others place to make comparison on our favourite music based on our CDS3s and my Garrard 401 against his LP12.
This became a ridiculously long topic on pfm and ran for weeks with Bub ranting that the test was invalid due to the lack of Mana under the amplifiers and the ATC speakers. It was acknowledged at the time to have been the longest thread ever.
The final result was that I preferred and kept the NAP300/Briks and he kept his ATC SCM100ASLs.
Also I preferred my Garrard 401 and so did he.
I did say that the Briks and the ATC SCM100ASLs were a pretty close damn thing.
Remembering this reminds me of the energy and enthusiasm we had back in those days, the thought of lobbing two sets of oversize speakers around today would fill me with dread.
Well, I have owned active Briks and ATC SCM100ASLs and in my experience they are not remotely close! The ATCs do much more of “all” than the Briks.
I have never heard active Briks which is one of my Hifi regrets. The thought of trying to convince my wife that we should have even more power amplifiers fills me with dread.
I am one of those creatures who prefers the omnidirectional sound and today the Briks have gone and have been replaced by Shahinian Arcs and they are for keeps.
I had some Shahinian Obelisks too. They did even less of “all” than the Briks, although occasionally seductively! Active ATCs have their amps inside the cabinets, so they are extremely neat domestically. You should try some again. Better sound, happier wife. Win win!
Yes it does make cosmetic sense to have active speakers and I would be quite happy to own a pair of active ATCs. I did say earlier on that it was a damn close thing.