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Post by John on May 9, 2020 13:42:23 GMT
According to this different ways of achieving isobaric I am using push/pull
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Post by John on May 9, 2020 13:49:30 GMT
I guess not really isobaric as not in a box
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Post by MartinT on May 9, 2020 14:47:56 GMT
It's not isobaric at all as your cones are moving in different directions according to your description. You are therefore achieving the sum of the surface area of the two cones and no cancellation.
Forget polarity, in an isobaric configuration, the two cones are moving in the SAME direction. You are therefore achieving the surface area of one cone and get cancellation if not in a closed box.
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Post by Clive on May 9, 2020 16:07:35 GMT
The cones move in unison, they are wired in opposing polarities to achieve this. It's tricky to explain clearly...
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Post by MartinT on May 9, 2020 16:11:25 GMT
Ah ok, so they're isobaric and there is bass cancellation.
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Post by John on May 9, 2020 19:01:40 GMT
Martin, please watch the video I linked into earlier (why open baffles rule) as it explains how dipole bass works and why it sounds good in most rooms.
The bass is not firing into the whole room, it is a bit more directional than that. It does not fire into the sides, this is a good thing as fewer room modes.
The only reason my bass does not go down any lower than 28hz is the drivers are not designed to go lower. Compare the Daytons the UM18 go down a good bit lower in Hz and have higher Xmax. Vic has a great trick where he can show the bass going subsonic. Ask Ali how good the bass is in Vic system.
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Post by John on May 9, 2020 19:07:33 GMT
 bass by John Cahill, on Flickr Both drivers are firing at the same time in the same direction as one is wired out of phase |
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Post by MartinT on May 9, 2020 19:55:03 GMT
Yes, I can see that John. It's isobaric loading but without a baffle and will give you cancellation. That's why deep bass is difficult to achieve without big drivers and loads of power.
Something you wrote earlier led me to believe they were working in expand/contract mode (drivers in opposition), but clearly not.
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Post by John on May 9, 2020 20:26:10 GMT
Getting the right driver and having plenty of power is the key
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Post by Clive on May 9, 2020 20:34:36 GMT
Power...yes I’m running around 1kw....easy with class d
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Post by John on May 10, 2020 6:50:30 GMT
Yes that the key easy to get enough power to make it work
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Post by Eduardo Wobblechops on May 10, 2020 19:02:34 GMT
Cheers John, it was a bit of a Damascus moment for me at Vic’s, as far as bass and how it’s possible to reproduce it in the home cleanly is concerned.
As the Yanks have it- “ There’s no replacement for displacement” :-)
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Post by Eduardo Wobblechops on May 10, 2020 19:04:41 GMT
The difference is not subtle I think you would like I think he now has drivers that match the bass in terms of effortless scale and detail Sounds a bit familiar but with a wood frame in this case.  Love to hear those sometime Clive. |
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Post by Mr Whippy on May 18, 2020 19:38:15 GMT
Have you tried the bass drivers in a vertical array? Thought perhaps the floor could be used as a reinforcement with just one driver. And can I ask where you got the scaffolding from? Looked on eBay but couldn't find a mini type. I suppose an alternative could be found.
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Post by John on May 18, 2020 20:33:50 GMT
The frame was a place up in North East England. They will cut the frame for you.
I actually going to try vertical array later this week. I know it works for Clive.
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Post by Clive on May 18, 2020 22:27:12 GMT
  Big step forward today. I rotated the pairs of bass drivers 90 degrees. Now they drive the room properly. I get very consistent bass as I walk around the room. Really...this is a huge improvement. |
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Post by MartinT on May 18, 2020 23:05:57 GMT
I would not have believed it would make a difference. Nice!
Is the carpet a Russian Bukhara?
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Post by John on May 19, 2020 4:19:00 GMT
Clive vertical modification seems to be very much room dependent. Our mutual friend tried and it made his bass performance worse. I suspect this works for Clive as his speakers were firing back into a bay area and this was causing room modes. It is good to know the design has the potential to use different angles to help with room modes.
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Post by Clive on May 19, 2020 8:27:25 GMT
The carpet is Turkish. Excuse the state of the walls but it's a cellar room and whilst fairly dry it's not perfect. Here's the inspiration for the change in setup last night. Now I have some understanding of why Vic's speakers sounded poor in my room. It's all about the bass driving the room...which has terrible dimensions. Note the optional change in orientation of the Celestions.  |
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Post by MartinT on May 19, 2020 8:45:02 GMT
It's worth checking, I bought mine in Turkey but it's actually Russian. Looks very similar to yours. |
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