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Thread: The biggest debate in the history of humankind -Tannoy crossovers original vs new.

  1. #221
    Join Date: Nov 2011

    Location: wirral

    Posts: 245
    I'm frank.

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    Digging around there are a few of these or similar designs. Briggs did some in th'olden days.
    Dual chamber vented aperiodic. Fostex do a ported one for the FE83E, they call it a double bass reflex where the upper chamber is ported into the larger 2/3 section....
    There seems to be a 1/3;2/3 ratio where the upper chamber behaves more like leaky sealed and everything below Fb is 'vented' into the lower ported chamber which is tuned to the full enclosure volume.


  2. #222
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

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    Quote Originally Posted by Denzil View Post
    Hi Marco,

    I have a question re Lockwood cabinets to which I've found no answer anywhere on the planet.

    The felt on the aperiodic shelf, can you please describe it. It it dense ? Is it very porous and soft ? Is it like the felt used to line car subwoofers ? How thick is it. And is the felt in your Lockwoods the original felt ?

    Regards,

    Denzil
    Hi Denzil,

    Just popping in quickly, as I'm busy. It's a thick woollen felt, like this: https://hardy-hanson.co.uk/industrial-wool-felt/

    That's what you need, but filled with wool wadding, to bulk it out

    And yes, there's no doubt in my mind that the employing of an aperiodic shelf and vent is a major factor [no pun intended] as to why, to my ears, Lockwood Major cabinets make Tannoy 15 MGs (or Reds, as I believe were originally used) 'sing' like no other. No loudspeaker enclosure is perfect of course, but for me they just sound so 'right' in those cabs.

    I'll come back to answer some posts [Hi Frank] as soon as I can.

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


  3. #223
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 746
    I'm matt.

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    Quote Originally Posted by cooky View Post
    Digging around there are a few of these or similar designs. Briggs did some in th'olden days.
    Dual chamber vented aperiodic. Fostex do a ported one for the FE83E, they call it a double bass reflex where the upper chamber is ported into the larger 2/3 section....
    There seems to be a 1/3;2/3 ratio where the upper chamber behaves more like leaky sealed and everything below Fb is 'vented' into the lower ported chamber which is tuned to the full enclosure volume.


    Good find! - It's interesting what you can learn from old books. Although some information is clearly wrong, you do find the odd nugget of gold.

    The Double-chamber reflex is mentioned in the Great Sound Stereo Speaker Manual and also in one of my other book IIRC, but I don't think I've seen the Dual-chamber vented aperiodic mentioned anywhere.

  4. #224
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

    Default

    Here's another shot of the wool felt and the overall thickness of the material:



    Defo WOOL - do not use anything else if you want it to have the same acoustic properties.

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


  5. #225
    Join Date: May 2020

    Location: Goa, India

    Posts: 143
    I'm Denzil.

    Default

    Quote Originally Posted by cooky View Post
    Digging around there are a few of these or similar designs. Briggs did some in th'olden days.
    Dual chamber vented aperiodic. Fostex do a ported one for the FE83E, they call it a double bass reflex where the upper chamber is ported into the larger 2/3 section....
    There seems to be a 1/3;2/3 ratio where the upper chamber behaves more like leaky sealed and everything below Fb is 'vented' into the lower ported chamber which is tuned to the full enclosure volume.

    This is a great find. Thanks so much. I wonder why this kind of design has been more or less abandoned in today's world ?

    Denzil
    https://www.instagram.com/elsewheregoa

  6. #226
    Join Date: May 2020

    Location: Goa, India

    Posts: 143
    I'm Denzil.

    Default

    Quote Originally Posted by Marco View Post
    Here's another shot of the wool felt and the overall thickness of the material:



    Defo WOOL - do not use anything else if you want it to have the same acoustic properties.

    Marco.
    This is excellent information, exactly what I was looking for !

    Thanks Marco.

    Denzil
    https://www.instagram.com/elsewheregoa

  7. #227
    Join Date: May 2020

    Location: Goa, India

    Posts: 143
    I'm Denzil.

    Default

    I think I have cracked the aperiodic code (at least for my speaker cabinets)



    I will listen to them for another day before I put down all my observations.

    All this wouldn't have been possible without all your help !!!

    Denzil
    https://www.instagram.com/elsewheregoa

  8. #228
    Join Date: Oct 2010

    Location: Dorset

    Posts: 44
    I'm Mike.

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    Any update?

  9. #229
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

    Default

    Yeah, the suspense is killing us!!

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


  10. #230
    Join Date: May 2020

    Location: Goa, India

    Posts: 143
    I'm Denzil.

    Default

    Quote Originally Posted by Marco View Post
    Yeah, the suspense is killing us!!

    Marco.
    I've just applied for a patent. And as soon as that comes through, I'll publish a paper here Marco (I'm open to businesses partnership).

    But on a more serious note, I've been preoccupied with several matters. And therefore the delay. However, I did have the time to open the cabinets three times to fine tune them.

    I will publish all details here as soon as I have the time. It's all very interesting !

    Regards,

    Denzil
    https://www.instagram.com/elsewheregoa

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