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Deep End DIY - My first speaker project


acg

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The horns will have a pair of 30mm diameter aluminium rods that screw into their rear (on 10mm threads).  See below for an illustration of the tweeter...
 
59110f97d6700_HornConnection1.jpg.210d3f286c54f8c344fc2dc495b4da1f.jpg
 
 
These rods will pass through a pair of sleeves in the frame and at the rear will be a third plate through which a 10mm bolt will pass and then screw into the back of each rod.  Twist the pair of bolts and the driver moves forwards and backwards.
 
59110f96da9b7_HornConnection2.jpg.b8f4ad05687e2619e19a368560b892ef.jpg 
 
 
Clear as mud!
 
 

A picture tells a thousand words mate.
I'm trying to work out how to mount mine. Mine are very different to yours though. Very nice work with the drawing. Brilliant to look at.

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Excuse the mess.

 

I've rearranged my room to suit my preferred theoretical speaker layout.  The desk is in a much better position from a number of functional perspectives and it is where I would like it to remain.  The ML1 standmounts have been jury rigged in the location where the drivers of the horns are anticipated to be although somewhat lower due to the elevation limitation that I have with the custom childrens chair speaker stands (patent pending).  Have a look at the photos below...

 

591249bf9e971_Excusethemess.jpg.e2208fb7d6c28191c7c7919e6d13e631.jpg 

 

591249c19bc2d_JuryRig.jpg.25686bc49b2b14b693fbe4c01dfbc804.jpg

 

Notice the Ribbonflex XLR microphone cable!!!

 

591249c2160e8_MicCable.jpg.50e47fc623b22344039d85e48587acb9.jpg

 

 

The room sounds "ok" in that it has the standard problems you would expect from an untreated room in the form of flutter echo and bass that seems to roll-on for too long.  The green-glued floor boards and rear wall along with the wall of glass windows behind the listening chair are all quite useful bass traps in their limited scope and I think that the raw response below is not too bad. Note that the little standmounts sign off at about 40Hz which at least partially explains the rolloff below that point.

 

591249c02790f_FirstRoomSweep.thumb.jpg.988458b70062c97e98b7e92ce4b53d17.jpg

 

Big suckouts at 100Hz and 300Hz and other more minor additions and subtractions along the way.  It will be interesting to see how absorption placed in the room will affect this graph, especially absorption placed behind the chair which is where those two major suckouts are sourced...reflections off the windows.

 

The reverb plot shows 0.35s minimum at the 100Hz null with 0.4s at 300Hz and 10kHz.  Average would be 0.5s above Schroeder but the reverb time for the bass blows is three times longer at 65Hz and who knows how long below that.

 

591249c0a3370_FirstRT60.thumb.jpg.d537c3e86ade3b6b2a55a1b606021a09.jpg

 

I also produced a waterfall plot but think that I need to alter the separation time between the sweeps to get a better idea of how long it takes those frequencies to dissipate.

 

591249c133d31_FirstWaterfall.thumb.jpg.af0bb0c1c5b9bcc155ce45f376a75e3e.jpg

 

These are my first ever room measurements.  I am pretty sure that REW is not setup properly given the scale readings on the graphs, but I will figure it out one day.

 

Discuss.

 

 

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Guest guru

With that roof profile and being across the room, I think you have chosen the most difficult of layouts possible only based on experience in very similar rooms. Be prepared for the odd hanging baffle or 3 from the centre line pitch and then some. Given the number of drivers you are trying to integrate as a whole, I would have thought listening distance from the driver would have been the major factor in choice of listening position as relative near field seating with multiple driver large speakers can be a very unusual experience, just past history showing and as I have only listened to the big Cessaro and Advantgarde horn speakers, your units may perform completely differently. 

Good luck anyway.

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21 minutes ago, Newman said:

Minor detail: Schroeder is a property of larger spaces and does not apply to home listening rooms.

 

 

 

 

 

 

 

My memory from reading Tool is that it is the boundary between discrete and diffuse sound fields:  I thought every room had Schroeder frequency.

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4 minutes ago, guru said:

With that roof profile and being across the room, I think you have chosen the most difficult of layouts possible only based on experience in very similar rooms. Be prepared for the odd hanging baffle or 3 from the centre line pitch and then some. Given the number of drivers you are trying to integrate as a whole, I would have thought listening distance from the driver would have been the major factor in choice of listening position as relative near field seating with multiple driver large speakers can be a very unusual experience, just past history showing and as I have only listened to the big Cessaro and Advantgarde horn speakers, your units may perform completely differently. 

Good luck anyway.

 

You are probably correct, but at least the monitors on my desk are much more clear (less sun affected) when placed in that corner and the speakers see a symmetric room profile (the crown in the roof is not equal).  We will see, it is all an experiment at this stage.

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There is something going on that I need to get to the bottom of.  I thought I would retake the measurements now that the cleaning truck next door has buggered off and things are a bit quieter...what I got was very different even though I have not touched any knobs on the Focusrite Scarlett or changed REW settings...have a look below (aqua was this morning, magenta was just now at lunch)...I've got some reading to do.

 

59127cf203869_Somethinggoingon.thumb.jpg.d9930a062844633209f89f1671932d22.jpg 

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3 hours ago, acg said:

Yep, two speakers playing at the same time.

 

You almost never want to do that.

 

If you play two speakers together, the result is dominated by how well aligned the speakers are in amplitude and time.....   also, if you play two drivers together in a multi-driver speaker.  The result you see is dominated by the crossover (and how well the two sources are aligned in amplitude and time).

 

From now on, use the lowest number of sound sources you can ...... if that is >1, then consider very carefully.

 

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1 hour ago, acg said:

There is something going on that I need to get to the bottom of 

 

They have different smoothing.   Assuming that is not it......   and that microphone or speaker position is not changed, then try computer reboot, and power cycle of your audio interface

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7 minutes ago, davewantsmoore said:

 

They have different smoothing.   Assuming that is not it......   and that microphone or speaker position is not changed, then try computer reboot, and power cycle of your audio interface

 

^^^ in bold is the only thing that changed in between...a restart for a windows update.  

 

 

11 minutes ago, davewantsmoore said:

 

From now on, use the lowest number of sound sources you can ...... if that is >1, then consider very carefully.

 

 

The single sound source thing sounds logical...I'll just use one (two way) speaker.

 

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5 hours ago, Newman said:

Minor detail: Schroeder is a property of larger spaces and does not apply to home listening rooms.

 

5 hours ago, acg said:

My memory from reading Tool is that it is the boundary between discrete and diffuse sound fields:  I thought every room had Schroeder frequency.

 

Small rooms (as found in homes) never achieve diffuse conditions.

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2 hours ago, acg said:

There is something going on that I need to get to the bottom of.  I thought I would retake the measurements now that the cleaning truck next door has buggered off and things are a bit quieter...what I got was very different even though I have not touched any knobs on the Focusrite Scarlett or changed REW settings...have a look below (aqua was this morning, magenta was just now at lunch)...I've got some reading to do.

 

59127cf203869_Somethinggoingon.thumb.jpg.d9930a062844633209f89f1671932d22.jpg 

 

IME this happens when the mic or its preamp isn't turned on, or the PC has defaulted to using its usual/onboard mic.

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Just had a 40 minute listening session with my Mum who does not get over this way on her own very often.  Like a true music lover she hogged the sweet spot the whole time!

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On 5/9/2017 at 6:54 AM, acg said:

So, three days straight of drilling steel and including the efforts of the previous weekend I'm up to about 35 hours on the tools to get the Bass Cannon prototypes, Horn Stacks and DSET chassis' ready for powdercoating

 

...another 17 hours on the tools over the weekend...I seemed to do a lot to achieve not very much although I did tap a LOT of holes...now up to 52 hours total steel fabrication time.  Welder is lined up for next week so I had better pull out my finger to get something ready for him!!

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...another 17 hours on the tools over the weekend...I seemed to do a lot to achieve not very much although I did tap a LOT of holes...now up to 52 hours total steel fabrication time.  Welder is lined up for next week so I had better pull out my finger to get something ready for him!!

Nothing like a deadline to keep you busy!

Sent from my SM-G900I using Tapatalk

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drilling and tapping my favourite job (not) haha, stick at it Anthony 

Wish you well and no broken taps in the job for extraction 

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7 minutes ago, 125dBmonster said:

drilling and tapping my favourite job (not) haha, stick at it Anthony 

Wish you well and no broken taps in the job for extraction 

 

My brother-in-law dropped in yesterday and was amazed that I had not broken a tap in the 300 odd holes I have done so far.  He wanted to know if I was going too slow...haha...but I use plenty of cutting fluid and it all seems to go smoothly.  There are quite a few taps into the sides of steel and aluminium plate that will test my patience though...I'm leaving those for last and will only do them in the morning hours when my concentration is better.

 

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1 hour ago, acg said:

 

My brother-in-law dropped in yesterday and was amazed that I had not broken a tap in the 300 odd holes I have done so far.  He wanted to know if I was going too slow...haha...but I use plenty of cutting fluid and it all seems to go smoothly.  There are quite a few taps into the sides of steel and aluminium plate that will test my patience though...I'm leaving those for last and will only do them in the morning hours when my concentration is better.

 

Yes, watch out for the aluminium, cast Aluminium in particular. One second of concentration lapse and pop, opps.

 

Sounds like you have it under control though. I use crc or rust penetrant something similar for the aluminium cutting and blow the threads/ cutters clear all the time

 

Thanks for posting this rather special build :) watching on.

 

 

 

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Took a few moments to tidy up the edges, wash, prime and then paint the constrained layer damping pieces of 1mm aluminium for the amplifiers.  102 pieces in all, but in the name of expediency I just laid them out on pallets and then painted the whole pallet at once.  Before the paint dried on the second coat I shifted the pieces onto clean paper.  Only one side needs painting, and they don't really need painting at all because they will be internal to the amplifier, but I just like the look of a nice amplifier "guts" when I am working on it.  The non-panted side will affix to the vicoelastic polymer which will then fix to the panel of the amplifier that is to be damped.

 

CLD1.jpg.aa7ab4cda1e1ee4a7da34ae9640dfc7a.jpg

 

Bloody wind...it whipped up a little and flipped a couple of pieces on the  bottom right corner of this pallet ^^^^.  I've since touched them up.

 

Pallet #2...

 

CLD2.jpg.6f4dca0a9a31cd2c84ea8f175d4f5dde.jpg

 

Pallet #3...

CLD3.jpg.58bc5b2c969eb787506542b0b4ab4791.jpg

 

And even a couple of larger pieces hanging from the clothesline...

 

CLD5.jpg.980561ee2d65889110ed9822180c38aa.jpg

 

I'll leave them out there in the yard for a couple of nights and then bring them in before it rains Thursday evening.  The paint takes weeks to cure properly so they will sit on the floor of my office for a while to dry.

 

 

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