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  1. #521
    Join Date: Mar 2012

    Location: Gloucestershire

    Posts: 3,950
    I'm Paul.

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    Quote Originally Posted by MikeMusic View Post
    Well done Paul

    Not Brand X then ?
    Might be!

  2. #522
    Join Date: Mar 2012

    Location: Gloucestershire

    Posts: 3,950
    I'm Paul.

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    Completed Crossovers for Tannoy 385A drivers used in GRF cabinets.

    The customer provided me with boards purchased elsewhere some time ago. The values were inconsistent with Tannoy's 385 circuit, so almost all components had to be scrapped and the boards rebuilt from scratch, save for the LF Cross-caps. I replaced the existing ferrite cored LF with an air core of the correct value for both inductance and DCR. The HF was the wrong value so this was replaced with a suitably rated ferrite cored inductor of the right value. There was no room to get an HF air core to fit and of the two, it was probably more important to have the LF inductor converted to an air core as there is less chance of saturation (in the case of the Tannoy circuit). This is a tried and tested solution.

    The notch filter inductor was wound back to the correct value and the existing resistor for the notch circuit replaced with the correct value (original was the value used for the 315 and not the 385). Amazingly, the shunt resistors in the HF circuit had been omitted completely so far too much treble energy would have been going through to the horn loaded tweeter.

    The boards look a little battle scarred now, but live to fight another day and the GRF's these belong to should now sing sweetly.



    HF cap value was wrong (value used was for the Monitor Gold and not the HPD) so that was also replaced, along with the bypass cap (also not the correct value).
    Last edited by Reffc; 05-12-2014 at 12:30.

  3. #523
    Join Date: Mar 2012

    Location: Gloucestershire

    Posts: 3,950
    I'm Paul.

    Smile Reference Raptor....first photographs

    Perhaps a little ahead of myself at this stage but thought it would be good to get feedback on overall aesthetics for the new Reference Raptor stand mount. Here it is...as yet unfinished, sporting Scanspeak Revelator and illuminator drivers. It's very substantial in construction, internally braced and uses slow grown Latvian Birch ply as the main cabinet material. Crossovers are still a work in progress but first listen is this evening. The cabinets need finishing, grilles need to be made and everything needs to be tidied up but always useful to get some general feedback.

    eg...would folk like these in self-finish (ie Birch) Danish oiled or veneered with Rosewood, Walnut, Cheery or something else? It does add cost but as these are a hand made loudspeaker it's anticipated that orders will be for individualised finishes to suit customer tastes.






  4. #524
    Join Date: Oct 2011

    Location: Charente, France

    Posts: 3,541
    I'm Nodrog.

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    Instant reaction is veneer or paint finish. I don't like the ply exposed on the front edges no matter how well they are finished. Then again, I'm not in the market and others might actually like the look. Pretty shape once its finished off.

    I suppose the grilles would come right to the edge but like many, I listen grilles off most of the time when on box loudspeakers.

    As a matter of interest, why do you always port load your speakers? I can't remember a ported speaker I didn't prefer once the port was closed off.

  5. #525
    Join Date: Mar 2012

    Location: Gloucestershire

    Posts: 3,950
    I'm Paul.

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    Quote Originally Posted by Gordon Steadman View Post
    Instant reaction is veneer or paint finish. I don't like the ply exposed on the front edges no matter how well they are finished. Then again, I'm not in the market and others might actually like the look. Pretty shape once its finished off.

    I suppose the grilles would come right to the edge but like many, I listen grilles off most of the time when on box loudspeakers.

    As a matter of interest, why do you always port load your speakers? I can't remember a ported speaker I didn't prefer once the port was closed off.
    Thanks Gordon. The grilles will come half way to the exposed ply edges so there'll be a "frame" around them. I personally prefer this to taking them full width.

    RE porting..it's the only real way of getting bass from a small enclosure (without using a less efficient loading or more complex loading such as isobaric or series vented bandpass loading and these are a medium sized stand mount half the size of the Rhapsodys). You're also constrained by the T-S parameters which determine speaker volume and best loading method. I hear what you say about porting but in reality a lot (majority?) of small ported designs are deliberately tuned for a raised hump at between 60 to 80 Hz as this is what sounds impressive on first listen. Many also use choked porting where the volumetric airflow rates exceeds 7m/s and that is audible. A properly implemented ported design is a different thing entirely and I can guarantee that with the Rhapsodys for example, I defy anyone to identify them as ported if listening blind. The other issue with many ported designs is that the power efficiency factor is lowered if the port isn't correctly tuned for the specific relationship between cab volume, speaker QTS and speaker VAS. This means lost efficiency and potentially can alarmingly raise the demands of the driving amplifier as well as result in damage to the speaker. Ported designs are very difficult to get right but done properly, they sound good.

  6. #526
    Join Date: Apr 2012

    Location: South West of England

    Posts: 278
    I'm Will.

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    Looks great Paul, I like the attention to bracing and the sloped front baffle. They'll look great when finished.
    Radford Revival
    www.radfordrevival.co.uk

  7. #527
    Join Date: May 2012

    Location: Maidstone

    Posts: 999
    I'm James.

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    Personally I tend not to like light coloured woods, I much prefer rich warm colours. I had some veneered cherry speakers that were just incredible to look at, real pieces of furniture.
    Source: Heavily modified DDDAC using MacBook Pro.
    Amplification: Pre amp-Stereo Coffee pre amp on steroids.
    Power amp- Rather large Colin Wonfor Class A power Amp
    Speakers: Lampizator P17 Open Baffles
    Accessories: Klotz 500 DIY Interconnects & DIY speaker cable sounding better than anything commercial.
    All powered from a Mother Trucker BPS with a dedicated consumer unit with 10mm armoured radial back to the house tails after the meter.

  8. #528
    Join Date: Jan 2011

    Location: Bristol, UK

    Posts: 275
    I'm Stephen.

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    I like the front baffle profile. Reminds me of Peak Consultant. I also note those drive units are top notch so should be a top performer.

    Regards

    Cyclopse

  9. #529
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 42,233
    I'm Geoff.

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    Quote Originally Posted by Reffc View Post
    RE porting..it's the only real way of getting bass from a small enclosure (without using a less efficient loading or more complex loading such as isobaric or series vented bandpass loading and these are a medium sized stand mount half the size of the Rhapsodys).
    Yes, a proper compact speaker that does extended bass is rare and as you say, tend to be less efficient or (and) complex. I recall hearing some surprisingly deep bass from the AR6 (sealed box) and Linn Sara (Isobaric).
    "when common sense, logic and plausibility are excluded. All that remain are foolishness and lies"

  10. #530
    Join Date: Sep 2014

    Location: brighton uk.

    Posts: 4,503
    I'm jamie.

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    Quote Originally Posted by Reffc View Post
    Perhaps a little ahead of myself at this stage but thought it would be good to get feedback on overall aesthetics for the new Reference Raptor stand mount. Here it is...as yet unfinished, sporting Scanspeak Revelator and illuminator drivers. It's very substantial in construction, internally braced and uses slow grown Latvian Birch ply as the main cabinet material. Crossovers are still a work in progress but first listen is this evening. The cabinets need finishing, grilles need to be made and everything needs to be tidied up but always useful to get some general feedback.

    eg...would folk like these in self-finish (ie Birch) Danish oiled or veneered with Rosewood, Walnut, Cheery or something else? It does add cost but as these are a hand made loudspeaker it's anticipated that orders will be for individualised finishes to suit customer tastes.





    imo those cabinets need an exotict veneer,ie rio rosewood etc,im an ex cabinet maker as you know paul and for me those quality speakers are crying out to be veneered,however good the quality of the ply-wood is in my eyes it just says "cheap" to me.

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