Monacor SP-310CX Coaxial Driver MLTL's

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Toppsy
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#1 Monacor SP-310CX Coaxial Driver MLTL's

Post by Toppsy »

These drivers have excelled in my 3-way Open Baffle speakers so I asked Scott to design us a box speaker solely for these coaxial drivers. another reason for making these test mules is that Chris has also been rather taken by the performance of these drivers and has expressed an interest in a smallish box speaker for them to try out at his place.

The driver is a 10" (250mm) PA bass speaker of 96dB efficiency with a coaxially arranged 1" (25mm) horn tweeter of 105dB efficiency. It requires a 2-way filter that Scott is designing based on the XO we used on the OB test baffles features on my OB project thread.

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So here they are: As this will not be part of the Reiver Acoustic catalogue this is offered as a DIY build project for anyone wishing to make a pair. The plan is CAD drawn and posted below. I can provide larger image copies for interested parties but will not be publishing the XO circuit. This will be only available by direct contact by email to me or Scott.

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These are quite a simple box to make, but having access to a CNC table saw I had a set of basic panels cut for me for ease of a quicker build and then routed the holes for the driver and port tube and braces.

One cabinet is almost complete and to date has only taken me most of today.

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Should have these almost completed by tomorrow evening if the weather holds.

I shall be taking these to Owston for feedback and comment, though I might have to ask Chris to take them in his car as I doubt I'll have any spare room in mine as I am taking my 3-way Open Baffles.
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andrew Ivimey
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#2 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by andrew Ivimey »

Ooooo very interesting. Where do these exotic beasts come from and would I have to mortgage the house!?
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#3 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by Cressy Snr »

Shoddy as ever! :D
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#4 Re: Monacor SP-310CX Coaxial Driver MLTL's

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andrew Ivimey wrote: Sat Apr 28, 2018 9:14 pm Ooooo very interesting. Where do these exotic beasts come from and would I have to mortgage the house!?
Andrew, They are not that expensive. Blue Arran retail them for £155 + VAT http://www.bluearan.co.uk/index.php?id= ... e=category Not sure if they are available cheaper on Ebay.
You can buy the drivers direct from me at a discounted price since I have a trade account with Monacor UK. Same goes for any the Monacor speaker drivers and accessories.
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#5 Re: Monacor SP-310CX Coaxial Driver MLTL's

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Cressy Snr wrote: Sat Apr 28, 2018 9:32 pm Shoddy as ever! :D
Steve,
From your posted up images just as shoddy as your new Fane FR speakers, of which from your reported performance feedback I am looking forward to hearing.
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#6 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by Toppsy »

For some reason I forgot to include a photo of the component cabinet parts that make up a single speaker, so for the record:

Image

No further build progress today as yet. A consequence of getting up late withbreakfast in bed and now I have to take my better half to do the weekly food shopping. So hopefuly will have the rest of the day for doing some gluing up.
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#7 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by Cressy Snr »

Comment moved to my own thread. :)
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#8 Re: Monacor SP-310CX Coaxial Driver MLTL's

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A little more build progress this morning. 2nd cabinet internal support frames and base and top glued in place. Side panels will be added next.

Image

Whilst this is gluing up making a start on making the grille frames that are attached in place with inbedded 8mm dia. x 3mm neo magnets
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#9 Re: Monacor SP-310CX Coaxial Driver MLTL's

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Progress on these speakers has been slower than I had originally intended. This is partly because of the nice weather where I have been out riding on the Harley and having to do some groundwork prep for Lynn's new garden summerhouse which will be delivered the end of the month.
However, the cabinets are now lined in my usual recycled 12mm thick wool carpet underlay:

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Underlay applied to the inside back of the front panel before this is glued in place. Lining is held in place with spray on adhesive:

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And here is a photo of the assembled cabinet. Note the 8mm dia x 3mm thick inlayed neo magnets for the front grilles:

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Having talked the finishes through with Chris, of the veneers I have in stock he much prefers the light woods than the likes of Santos Rosewood or American Black Walnut and has chosen Maple. This will be a challenge for me as the width of the leaves are only 200m so every panel will have to be back-to-back joined in good old book matched fashion. Anyway we'll have to see how this pans out.

I have ordered a new set of drivers and XO components. The new drivers should arrive next week but the XO components are not expected until around 20th May.

For the few who are following this thread I'll post up more photos and updates as and when I get around to the veneering.
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#10 Re: Monacor SP-310CX Coaxial Driver MLTL's

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Yesterday managed to cut and book match the maple veneer panels for the speakers. First time I have used proper veneer tape for joining panels prior to gluing them in place. The tape is water based and is wetted out using a sponge. It is very thin and glues down well. The published blurb states that as the paper tape dries it shrinks slightly so giving a very tight joint line. Be interesting when removing this tape, by whetting it out again with a sponge, if it leaves any glue residue on the veneer. A set of panels for a single speaker:

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One cannot really see the true grain parterning on the maple veneer from that photo so here is a close up image.

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Should have both speakers covered today.
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#11 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by gninnam »

Looking nice Colin - love the veneer 8)
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#12 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by Ant »

Ive used that type of tape Colin, it does work well, there was very little residue once I took it off. be careful when taking it off though, use as little water as poss to get it off, I used abit too much on the test piece and it bled into the veneer and swelled it very slightly so i got a bump in a few places along the joint once it dried out again. Use just enough to get it tacky again
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#13 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by chris661 »

Always good to watch your work, Colin.

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#14 Re: Monacor SP-310CX Coaxial Driver MLTL's

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Ant wrote: Thu May 10, 2018 1:58 pm Ive used that type of tape Colin, it does work well, there was very little residue once I took it off. be careful when taking it off though, use as little water as poss to get it off, I used abit too much on the test piece and it bled into the veneer and swelled it very slightly so i got a bump in a few places along the joint once it dried out again. Use just enough to get it tacky again
Many thanks for the tips Ant. I think I'll cut a sponge to the width of the tape wet it and use that to wipe over the tape.

I have now veneered the cabinets but have yet to remove the tape. I intend to leave this on for a couple of days to allow the contact adhesive to harden off some. In the past when I have used impact (contact) adhesive and had to join panels I used ordinary masking tape and removed the tape straight after gluing the panels to the cabinets. I found that after a couple of days drying time the seam had opened just a tad. I want to avoid this on these. Some photos with the veneer tape still in place:

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I am going to try a waxed finish on these speakers. This will be a first for me. I'm hoping this finish will not cause any shrinkage of the veneer when it would be whetted using acrylic varnish or oil. Finger crossed.
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#15 Re: Monacor SP-310CX Coaxial Driver MLTL's

Post by Ant »

I always use wax and haven't had any shrinkage issues, Ive found issues when using a wood dye and then wax, if you aren't careful the wax pulls the dye out and the finish goes mottled.
These should be fine, I like to use rustins wax as their clear wax seems to just pull out the grain rather than adding any additional colour. I found colron wax added a slight yellowy tinge.
Dont go mad with the wax, build up the coats like you would paint, thin coats are best for a smooth finish
And do wait the length of time it says, try to buff it out too early and it... Well it won't buff out and you will have to do it again.
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