MF 1000

Sub bass & bass Speakers with 18" Volt RV4564 drivers

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That’s only using the 15” radial bass driver ....but in a 350litre enclosure ....’kin huge !

makes me appreciate what I’m building if they are charging almost £6k ....and £600 for delivery is a little excessive

my new cab in 183 litres and tuned down to 12Hz by the way 😁😁😁 

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In between conference calls today I’ve managed to glue & screw 4 sides and the internal bracing - leaving the front and 1 side baffle unglued so its easy to fit the stuffing and sort the adjustable clamp for the rear of the driver magnet.

Hope to mount the driver tomorrow and start some testing in situ with REW .....hoping for some good results

Initially I’m going to try it with just the dead sheet dampening then slowly add in bubble wrap, fibreglass & wadding to tune it :nerves:

Edited by MF 1000
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It’s been a glorious day here so after mowing all my lawns I set to in the garage finishing off the final gluing up of the bracing, last pieces of deadsheet stuck in place then fitted the driver.

50C70009-CEAA-4D6F-92E1-511F4C915E5E.jpeg.192a31ea9e74752a0d5633c52e3bbeee.jpeg

pic showing the finished internals plus the funky blue deadsheet.

944567F7-8405-4020-A7E5-4578F4725DFF.jpeg.39dce4a0eabb7a63ca26e6919a090383.jpeg  A side view of the internals complete with adjustable rear brace for the driver magnet

043D9C73-18E2-4493-B39E-F55F396D1B29.jpeg.a9acd45a740bd15e9d59c878f3df6f75.jpeg  here in close up

and finally an assembled pic 

4065CA5E-7271-49E0-A568-31FE0D8DDDD6.jpeg.9ba67719a3432ef6ef87d09c92477227.jpeg

just the port outlet to make now - nice piece of walnut and a couple of hours routing etc

Had to find out how it sounds so a quick move with my trusty sack truck into the lounge, move the old cabinet out and .........It lives ...it’s ALIVE 😀
 

On with Yello - Touch CD and ......holy f**k Batman
 

first impression is a new layer of deep and textured bass and more ‘air’ around decaying notes etc.  On through various test trackS then finished off with Boellman Suite Gothique with the 16 Hz bass notes....wow this feels like a good leap forward.

ill do some measurements with REW tomorrow.

Edited by MF 1000
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30 minutes ago, MF 1000 said:

It’s been a glorious day here so after mowing all my lawns I set to in the garage finishing off the final gluing up of the bracing, last pieces of deadsheet stuck in place then fitted the driver.

50C70009-CEAA-4D6F-92E1-511F4C915E5E.jpeg.192a31ea9e74752a0d5633c52e3bbeee.jpeg

pic showing the finished internals plus the funky blue deadsheet.

944567F7-8405-4020-A7E5-4578F4725DFF.jpeg.39dce4a0eabb7a63ca26e6919a090383.jpeg  A side view of the internals complete with adjustable rear brace for the driver magnet

043D9C73-18E2-4493-B39E-F55F396D1B29.jpeg.a9acd45a740bd15e9d59c878f3df6f75.jpeg  here in close up

and finally an assembled pic 

4065CA5E-7271-49E0-A568-31FE0D8DDDD6.jpeg.9ba67719a3432ef6ef87d09c92477227.jpeg

just the port outlet to make now - nice piece of walnut and a couple of hours routing etc

Had to find out how it sounds so a quick move with my trusty sack truck into the lounge, move the old cabinet out and .........It lives ...it’s ALIVE 😀
 

On with Yello - Touch CD and ......holy f**k Batman
 

first impression is a new layer of deep and textured bass and more ‘air’ around decaying notes etc.  On through various test trackS then finished off with Boellman Suite Gothique with the 16 Hz bass notes....wow this feels like a good leap forward.

ill do some measurements with REW tomorrow.

So is the end game to have a second one of these, Keith? I've lost track...

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Oh yes ...a matching pair and possibly with top mounted CM30 monitors for the mid bass, midrange and top end following the AOS Laudspreaker design

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44 minutes ago, MF 1000 said:

Oh yes ...a matching pair and possibly with top mounted CM30 monitors for the mid bass, midrange and top end following the AOS Laudspreaker design

So the Kefs are going to be replaced then?

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I think so...I’ll. build one of the CM30 s ....minus the v expensive volt midrange (£500 a pop,) using a peerless domed midrange and see how they compare.  Main bonus would be a smaller footprint overall 

lots of value in the Kefs with 4 original B110s if I choose to break then down which would fund the new monitors etc 
 

Edited by MF 1000
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So here is the first comparison graph from REW.

37F98219-0759-4DCF-8F39-4A2B27C4EBF7.thumb.jpeg.1de437eacd54757524774eb71cbdafb0.jpeg

The RED curve is when I first obtained the Volts

The Green Curve was my last sweep with the old cabinets

The BLUE is with one new cabinet on the RHS 

All measurements are full range and from my listening position 

It’s clear that even in its raw state (and with only 1 new cabinet) that there is a 7-8dB lift in the bass response between 45Hz and 80Hz (around where most ‘musical bass’ notes occur)  .....I think with a bit of controlled ‘stuffing’ this will be even better ...but it does show that lining the inside of a very stiff cabinet with deadsheet (visco elastic damping) has a very positive effect on bass response.

Working away all this week so no time to tinker .....watch this space again as refinements take place.

Edited by MF 1000
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A wet day here so stuck indoors and had a play with adding some bubble wrap & wadding into the new cabinet

23370356-F8AF-4E53-BA68-8E85C27EFE60.thumb.jpeg.67399bb0ff4a188ef2d0e17db704eaa0.jpeg

the red curve is just with the deadsheet, and the Brian curve is with wadding etc.  
It’s raised the ultra low bass by around 5db but created a small dip around the 98 dB area which I think could be dialled out on the eq settings.

Sound wise the mix of bubble wrap & wadding has dampened some of the woolly low bass (great for movie sound effects) so I think there is a bit more to come yet.

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Build of the second cabinet is currently on hold as my supplier of accurately cut 30mm mdf is Liverpool based so Covid has intervened once again.

But this has allowed me the faster build time on the Volt/Scansoeak three way horizontal monitors that will partner the bass units long term 

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13 hours ago, MF 1000 said:

Build of the second cabinet is currently on hold as my supplier of accurately cut 30mm mdf is Liverpool based so Covid has intervened once again.

But this has allowed me the faster build time on the Volt/Scansoeak three way horizontal monitors that will partner the bass units long term 

I've been on the lookout for someone who can do accurate cuts, can you share who this is?

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Hi Frank

https://www.merseymdfplasandply.co.uk/cutting-and-edging-service/
 

they are on the border of aintree/bootle, supply & cut all thickness of mdf.  Not the cheapest but good quality and quote a 0.1mm accuracy.

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Had time today after starting my report writing at 7am to connect up the laptop to the system and run some sweeps with REW.

First issue I found was I have a problem with the amp that runs the Fostex Supertweeters.....I’d noticed the RHS one was hardly operational....now both have stopped  🙁

I adjusted the DCX settings to allow the Scansoeak units in the new monitors to go up to 20KHz and did an initial sweep.  
 

I’ve thought since having both monitors in situ that there was more space around instruments and a better front to back soundstage too. ......the initial sweep showed a far smoother midrange curve and then with some tweaking to the dsp settings I could extend the flat portion of the midrange and interestingly the Scanspeak units were giving my far more High end response.

All good then ....and a tweak on the eq for the bass end - and increase of 5 dB aided the curve even more 😀

72D43E72-0478-4009-856C-9616D3DC6A7D.thumb.jpeg.59cbe73d9f6495dcefefe48a71a081ea.jpeg

here is the before /after curve ....the before in this case (RED) being the KEF 104/2 speakers fir the mid bass/ midrange/HF and the purple the revised eq with the new monitors.  Even though it’s my kit/build/ ideas etc it’s a huge leap forward imho.

More to come I think as I refine things a bit more.

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