What would you do with these drivers?

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JohnG
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#76 Re: What would you do with these drivers?

Post by JohnG »

As this thread was touching base 'pardon the pun' on 'H' Frames, I began to revisit it to see what I could learn from.
Now ESL 57's are in the discussion, in my set up the OTA Rebuilt ESL 57's do not have a Bass delivery that seems inadequate.

I do have a interest in attempting to interface the 57's with a OB Sub Woofer, Ripole, 'H' Frame and 'W' Frame
have all been looked into for the wood work dimensions to work with 15" Drivers.

As for my supplying a little entertainment to the die hard Speaker Builders, as a result of my complete inexperience with this type of venture.
When Investigating H Frames, there was a discussion on the possible merits of not having Parallel Side Walls on a H Frame.

With this info to hand, I thought I would produce a H Frame that had a flexibility in how it was set up.

My intention is to produce a H Frame with a Top and Base that had a increased Width Dimension to that of the outside face of the Side Walls.
I believe I have a 75mm/3" overhang drawn on a plan.

This was to allow for a Side Wall for the 'H' Frame that can be hinged/swivel connected to the Drivers Baffle and the Side Wall.
This Swivel connection design is still to be thought out, I have a couple of ideas, one very basic one,
is a oversized rebate in the side wall, with the driver baffle set into the rebate with a void between the two materials.
The void can be sealed with a Soft Compressible Foam or a Low Modulus Silicone that has a high flexibility, allowing to maintain a seal and flex.

This design would have allowed a flexibility to reduce or increase the dimensions of the front and rear chambers, by swivelling the side walls, and allow for experiencing how variations to a non parallel side wall could produce in a room.

Beyond all the above Happy New Year to Audio Talk.
vinylnvalves
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#77 Re: What would you do with these drivers?

Post by vinylnvalves »

Finally got around to reconfiguring the crossovers to incorporate the seas drivers sub 100hz. More work than I wanted, ran out of computing power to run FIR’s for all the crossovers. So reconfigured the crossovers for conventional IIR filters adding the additional channels. ( learnt something new - theoretical group delay and measured can be different, needed an extra 0.05m on the 4K HP filter). So been playing with the extra drivers for a few hours now, it sounds different - leaner in the bottom end. I am currently only running a single seas per channel so a 10” compared to the 15” Supravox. So physical air movement is halved, and I am using half of a opposed h frame per channel... hoping sub 100hz channels are effectively mono.

Some more extensive listening and tweaking needed before I can say whether i buy the bullet and invest in the other channel of Seas drivers. The disappointment is that the OB sub only goes flat to 35hz, with an f3 of around 30Hz, so not really a sub more of an LF helper.
But to be fair there is very little material other than Yello and the like, piano or organs that go below 30Hz, in music I listen to.
vinylnvalves
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#78 Re: What would you do with these drivers?

Post by vinylnvalves »

Finally got around to reconfiguring the crossovers to incorporate the seas drivers sub 100hz. More work than I wanted, ran out of computing power to run FIR’s for all the crossovers. So reconfigured the crossovers for conventional IIR filters adding the additional channels. ( learnt something new - theoretical group delay and measured can be different, needed an extra 0.05m on the 4K HP filter). So been playing with the extra drivers for a few hours now, it sounds different - leaner in the bottom end. I am currently only running a single seas per channel so a 10” compared to the 15” Supravox. So physical air movement is halved, and I am using half of a opposed h frame per channel... hoping sub 100hz channels are effectively mono.

Some more extensive listening and tweaking needed before I can say whether i buy the bullet and invest in the other channel of Seas drivers. The disappointment is that the OB sub only goes flat to 35hz, with an f3 of around 30Hz, so not really a sub more of an LF helper.
But to be fair there is very little material other than Yello and the like, piano or organs that go below 30Hz, in music I listen to.
vinylnvalves
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#79 Re: What would you do with these drivers?

Post by vinylnvalves »

Just having an evening of listening to various albums, I have now concluded that these open baffle subs are doing what they should be doing, whilst playing Beth Harts latest album, the double bass is very prevalent (E chord ~40 hz ish) and the piano is going lower. The response is a bit hot, have had to knock a few db off as room gain is adding more than I thought. It’s interesting I have been playing lots of music, without really noticing the improved bottom end, it does show that most music doesn’t have much sub 50 hz content. Now I have to decide whether to splash some more cash to buy another 2 drivers so I can have a pair of push pull subs.
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IslandPink
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#80 Re: What would you do with these drivers?

Post by IslandPink »

OK so that's a single Seas driver as per your first post, used in one of the H frames. Did you use a bit of DSP EQ to pull up the low bass ?
Good to see you're getting somewhere with it. Is it showing much excursion at your current listening levels ?
"Once you find out ... the Circumstances ; then you can go out"
chris661
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#81 Re: What would you do with these drivers?

Post by chris661 »

vinylnvalves wrote: Wed Feb 17, 2021 8:30 pm it does show that most music doesn’t have much sub 50 hz content.
Depends what you listen to. I could name plenty of music with sub-40Hz content, and quite a lot with sub-30Hz. There are a couple of nutters in America that intentionally make music with strong infrasonic content, which they use many 18" subs to play back.


Mark, looks like he's using a pair at the mo - two drivers, one baffle.

Chris
vinylnvalves
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#82 Re: What would you do with these drivers?

Post by vinylnvalves »

IslandPink wrote: Thu Feb 18, 2021 6:16 pm OK so that's a single Seas driver as per your first post, used in one of the H frames. Did you use a bit of DSP EQ to pull up the low bass ?
Good to see you're getting somewhere with it. Is it showing much excursion at your current listening levels ?
No it’s a pair of drivers in an h frame push pull configuration being fed a mono signal. Next stage would be to make a second frame and add two more drivers. Each driver would be driven by a 500w amp - really only 300w at 3.5 ohms. So 1200w going into them.
I am using a 20Hz 2nd order LP filter to give the bass boost ( really just attenuating the higher frequencies) with 9db higher gain than the midbass driver.

You can see a shimmer on the drivers when the double bass is being plucked if it’s more than mm of movement I would be surprised
vinylnvalves
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#83 Re: What would you do with these drivers?

Post by vinylnvalves »

chris661 wrote: Thu Feb 18, 2021 9:00 pm
vinylnvalves wrote: Wed Feb 17, 2021 8:30 pm it does show that most music doesn’t have much sub 50 hz content.
Depends what you listen to. I could name plenty of music with sub-40Hz content, and quite a lot with sub-30Hz. There are a couple of nutters in America that intentionally make music with strong infrasonic content, which they use many 18" subs to play back.


Mark, looks like he's using a pair at the mo - two drivers, one baffle.

Chris
I could play the likes of Tool but it’s not a type of music I enjoy. My lads have lots of bands with low end content.Equally I don’t just play uncomplicated music because I makes the system sound good. Low are another band with a lot of low end content- too much if you can hear it all. Most Bass guitars only go to 40 hz with the most pronounced note being 80 hz, so my usual music doesn’t go that low. Maybe I need to clean my Telarc recording of the 1812 overture.. I can the test the tracking of the stylus at the same time as giving the subs a work out, mind you only for a few seconds.
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