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Deep End DIY - My first speaker project


acg

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So my daughter brought home the influenza mid last week and I got to look after her (had a mattress brought up to my office) and  what do ya know I ended up crook too.  Just in the last few hours am I beginning to feel like I will be able to do a proper days work tomorrow.  Proper flu with the aches and pains and temperatures and chills so I instead of paying work where I have to concentrate for long periods I decided to do some of the menial stuff toward my audio habit.  You know, the stuff where I don't have to think much but just do it...the monkey work.  Four days of that and I actually have achieved quite a bit but the room is a complete mess again!

 

At the start I just loaded up the aluminium CLD panels with the vicoelastic stuff because I could sit down and trace the outline of the part, dip the scissors in water and cut inside the lines.  A crappy job and one that I have not been looking forward to I can admit, but I did an entire day of it and I am abut halfway through I reckon.  Here are some of the parts on my floor...

 

5986ce928c5b8_CLDStarted.jpg.719b421f4eda798c62dd66afa02eba70.jpg

 

The OPT's were attached to their vibration platforms...

5986cd1d38d9d_OPTsandstuff.jpg.d98f227bbb9b9a700e25467c786eb72c.jpg

 

I also did the first mockup of the pneumatics that will be under the amplifiers.  I'll have to get a few little parts to finish that off properly.

 

5986cd1bdab2d_PneumaticsFirstDraft.jpg.8a9f7c1042d62c61839c9175e5eaaad0.jpg

 

Then there was some general assembly.  I was proper excited when I screwed in the tube sockets.

 

5986cd1a96917_TubeSockets.jpg.c837d98feb17357dadf35d4b5d045194.jpg

 

 

Starting from the base I even started putting together the amplifiers.  I moved a camping table upstairs and my daughter sat in a listening chair at one end and helped between colouring in and sleeping.

 

5986cd193e93a_Worktable.jpg.6fcfa5836cc2c2a0ad50a7d377c5941a.jpg

 

Upside down view of the base of the amplifiers...

 

Bottom.jpg.6560d591e5dca71a2e984b7b24ce4149.jpg

 

Capacitors.jpg.9a11a530193c33461c6baaaa5918ac18.jpg

 

...and right way up...they are some big filter caps!

 

 

Four days work, among other things, but it is nice to be underway.

 

 

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So my daughter brought home the influenza mid last week and I got to look after her (had a mattress brought up to my office) and  what do ya know I ended up crook too.  Just in the last few hours am I beginning to feel like I will be able to do a proper days work tomorrow.  Proper flu with the aches and pains and temperatures and chills so I instead of paying work where I have to concentrate for long periods I decided to do some of the menial stuff toward my audio habit.  You know, the stuff where I don't have to think much but just do it...the monkey work.  Four days of that and I actually have achieved quite a bit but the room is a complete mess again!
 
At the start I just loaded up the aluminium CLD panels with the vicoelastic stuff because I could sit down and trace the outline of the part, dip the scissors in water and cut inside the lines.  A crappy job and one that I have not been looking forward to I can admit, but I did an entire day of it and I am abut halfway through I reckon.  Here are some of the parts on my floor...
 
5986ce928c5b8_CLDStarted.jpg.719b421f4eda798c62dd66afa02eba70.jpg
 
The OPT's were attached to their vibration platforms...
5986cd1d38d9d_OPTsandstuff.jpg.d98f227bbb9b9a700e25467c786eb72c.jpg
 
I also did the first mockup of the pneumatics that will be under the amplifiers.  I'll have to get a few little parts to finish that off properly.
 
5986cd1bdab2d_PneumaticsFirstDraft.jpg.8a9f7c1042d62c61839c9175e5eaaad0.jpg
 
Then there was some general assembly.  I was proper excited when I screwed in the tube sockets.
 
5986cd1a96917_TubeSockets.jpg.c837d98feb17357dadf35d4b5d045194.jpg
 
 
Starting from the base I even started putting together the amplifiers.  I moved a camping table upstairs and my daughter sat in a listening chair at one end and helped between colouring in and sleeping.
 
5986cd193e93a_Worktable.jpg.6fcfa5836cc2c2a0ad50a7d377c5941a.jpg
 
Upside down view of the base of the amplifiers...
 
Bottom.jpg.6560d591e5dca71a2e984b7b24ce4149.jpg
 
Capacitors.jpg.9a11a530193c33461c6baaaa5918ac18.jpg
 
...and right way up...they are some big filter caps!
 
 
Four days work, among other things, but it is nice to be underway.
 
 
Bugger the flu. Poor bastard. Never any fun. But you've still made some decent progress. Nice work mate. You should be happy.
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13 hours ago, Upfront said:

Bugger the flu. Poor bastard. Never any fun. But you've still made some decent progress. Nice work mate. You should be happy.

 

I'm happiest about dropping 2kg with the 'flu.  That's 11kg since I started swimming again this year...five more to go.

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  • 2 weeks later...

Yes, the flu has subsided and I have had to jump into work to make up for lost time.   This morning I dropped off more steel for powdercoating and I've painted more stuff and have just primed the top plates for the amps with the aim of painting them in the next day or two. 

 

So things are moving along steadily but work is taking priority at the moment. 

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One Cannon is alive...

 

Got some time today for my audio project and decided that I wanted to get some life from a Bass Cannon.  It's well past due to get some concrete direction as to whether my ambitions for a 2m tall array of Cannons can perform in reality so I installed some more damping on the 10mm thick steel parts of the cannon (the flat back plate and the plate the driver screws into) and grabbed a bit of my fancy Bunnings figure eight speaker cable.  That Bunning cable is really fancy:  the ground is copper coloured wire and the positive is tinned.  Anyway, it sounds crap with speakers but will be good enough for this part of the project.

 

The first thing that I noticed is that there is a resonance in the Cannon when I scratch the driver.  ****!  It really sounded like crap just tapping the cone or scratching it and I became quite forlorn...maybe this is not going to work after all.  So I hooked it up to the amplifier and played one channel fullrange listening to Greta Bradman doing her show on ABC Classic FM.  Oh my, her voice sounded like complete rubbish, much more rubbish than I had hoped for even though I realise that I am using a 10" woofer to reproduce a female voice.  The music was awful but not as awful as Greta's voice.  Using the remote to switch between FM and mute you could hear the decay of the resonance after the music/voice had stopped.  Oh ****...that is awful!

 

So I went and had lunch just so I could think about things and realised that it sounded just like a flutter echo that you get in a bare room.  Mmmm...the Cannon is a metre long with a flat end and could well set up some nice standing waves that would excite the woofer cone on its very soft suspension which would end up a feedback cycle causing the slow decay.  That was my theory anyway and I was determined to go with it.  So I went up into the attic and brought down some leftover fibreglass insulation from renovating the office and decided to cut 5 circles the diameter of the Cannon and stuff them up the back behind the driver.  All up this is about 35cm of stuffing or one-third of the vacant area filled with fibreglass batt.  I screwed the driver back on and could not wait to scratch and tap the cone again to hear what it sounded like...it's way better...actually it is good...phwew.

 

Put Greta Bradman back on and her voice is soooo much better and there is no audible resonant decay when suddenly muting and the music sounds so much better.

 

 59a234470cb5e_Itsalive.jpg.8cf0c205f13b846282b9df824a27e678.jpg

 

So, I have steel vibration and ringing well under control...it is more inert than the ML1's and resonates with a knuckle rap at a lower frequency that that well-damped wood box and also for a shorter duration.  The standing waves inside the Cannon proved to be easily damped by a bit of fibreglass and I do like the look of it sitting there in its position in the room, so I am confident of moving to the next phase of the evaluation process, which is measurement.

 

I need to get my head around REW and my soundcard and calibrated mic so that I can evaluate different stuffing materials and volumes.  Can anyone point me to an idiots guide to setting up REW and using it to measure the performance of speakers?  

 

 

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12 minutes ago, 125dBmonster said:

Hi Anthony, have any juicy screen shots for the response curves on your bass cannon yet ? 

 

 

As it just so happens your timing is impeccable and I do have some ready at just this moment.

 

I like baselines.  They are essential for professionals and laymen alike and I am certainly a layman here.  So I measured at the listening position the left and right channels of the ML1 standmounts and then I measured a single Bass Cannon on the right.  The fullrange sweeps are shown below:

 

59a39b3bdb1cf_BassCannonsfirstMeasurements.jpg.fee4fd706fa05314f642800ae445c642.jpg

 

Same thing but limited bandwidth:

 

59a39b3c9c704_BassCannonsfirstMeasurements2.jpg.8f30756d7609510d62e0c62bc6cbab13.jpg

 

Yep, a Cannon certainly has more bass output than the ML1's.  This is all run using a SS amplifier.  When I measure the impedance of a Cannon it is currently tuned for a resonance frequency of about 50Hz which I intend to lower with further stuffing (it would be nice to knock 10Hz off that number but I don't know if that is possible...we will see) and as you can see by the graph it drops away at about 6dB per octave from somewhere near that frequency.  Room nodes obviously at about that frequency as well and as you go higher they appear with increasing regularity.

 

I'm not sure what to think about things at this stage.  The frequency response is more or less what the WinISD modelling showed so no surprises there and it looks like I have some peaks to try and tame at 40/80/120Hz.  I sat in the listening chair and put the REW sine wave generator on with the Cannon connected and I can hear 20Hz at these calibrated levels (75dB at the chair with one speaker running pink noise) and running up in frequency it was so easy to hear the frequency peaks and nulls...really brings home how important it is to get a correct bass response.

 

Anyway, thanks Matt.  That little tutorial got me underway to calibrating my kit and I think I have that side of things all under control now.  Now the harder part of correctly interpreting the information and plotting the correct path forwards.  At some stage I will have to bring the prototyped valve amp back into the game and install the huge bass output transformer to get an idea of how the Bass Cannons will behave with the higher output impedance of the 6C33C.  Mind you it is a vanishingly low output impedance for a zer feedback valve amplifier but I am expecting a little more output at and below resonance of the Cannons.  So if I can get the resonance of a Cannon to 40Hz or so I should end up with more bass output than these graphs above show.

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Hi Anthony

Looking good there except for the peak at 43 (ish)Hz although you may find it's an atribute induced by the room. The sudden ragged drop in SPL from 60Hz may also be of concern if wanting to use this part of the range in application.

 

At this point above everything else don't worry :) trying to be subjective

 

Room interaction

 

Would explore the possibility of doing the test in aeonic conditions, either outside or in a studio chamber. Second option is normally not available so try doing the test in a way that doesn't excite the room

1. mic as close as possible to woofer cone and at very low volumes (as low as you can within reason) with sound absorber surrounding the test (piles of bats works) This helps a great deal identify what interaction the room has

2. (possibly not desireable) Drag and groan the cannon outside and perform the test in an open area where the cannon's response is not affected by walls. As the low (bottom octave)  frequency response is not considered directional, floor or ground loading would be Ok so open field elevated minimally from ground (please experiment with heights off of the ground)

 

All this is to see whether the room itself is responsible for the peak or not or whether or not the upper response is effected past 60Hz

 

If the room isn't responsible, setting up a second order LR crossover to start rolling off at say 39Hz may provide a nice smoothing effect that meets up with the bass horn and you are on your way

 

Active DSP PEQ would be very handy :) but won't mention that again as you are employing passive filtering only.

 

Enclosure

 

1. Stuffing the enclosure ever tighter with absorb may not help and you could find you sacrifice the nice response you are getting at 20/35Hz now and only shift the peak further up the range if at all. General rule is sub enclosures do not use much more than enclosure damping materials as it has little effect otherwise within the low frequency band is less than half or even quarter wave length, sudden  reflective stop at end of tube though, may be an issue

 

2. Installing a baffle in the form of an angle over 3 thirds of the tube may solve the peak (resonant peak), even a circle or oval installed in the tube then turned at a 45 degree angle may help and well worth a try if all else fails

 

I have a personal belief that the 45Hz peak is being generated by resonant standing wave reaching the cone at that frequency would be an idea to do the maths on the wave length and the tube length. An easy way to find out is to experiment with another cannon w/o the end welded on.

 

Other than that the graphs look good, try using say 10 to 100Hz and 80 to 50dB as the scale to get a more precise and easier to read response graph.

 

Above all enjoy the experimentation looks and sounds like a lot of fun and play, wish I had more time for my system, particularly sub/mid integration as I am still faffing about with that and to be frank, it's the most difficult part of tuning any system, trust you to start at the hardest part of the task of tuning.

 

matt

 

 

 

 

 

 

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I don't know much and agree with Matt.

I have spent hours measuring (actually still am) and have learned a few things - essential to try to measure as close as possible in front of the speaker at the height it will be - on axis. If possible try different heights and distances. Not what you want to hear but do try measurements outside. 

What I do find interesting is that the canon on the right has several similarities with the ML1 on the right - in those instances I think it may be the room and not the speaker.

@almikel and @davewantsmoore

may be able to chime in.

 

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Thanks Matt.

 

One of the reasons for using the ML1's as a baseline is that I was hoping to be able to identify the room nodes and nulls.  If you compare just the green and purple lines in the graphs above (ML1 right and Bass Cannon beside it in the floor) you will notice very similar behaviour at about 40/80/120/190Hz for major peaks and 65/95/145/220Hz for major nulls.  I have just had a look at the Room simulator in REW and although it cannot sim my cathedral ceilings it is giving a result that "basically" mimics the graphs above.  The interesting thing with that tool is that you can identify the source of the particular peak or null:  most of my major peaks are caused by the length of the room (i.e. the axis in which the speakers fire) but the nulls are generally width nulls (from the side walls).  Is this good information and does it make the job of treating the room any easier?  Don't know.

 

Testing anechoically or in an acoustically "larger" environment would be nice but I am not sure exactly what I will learn by doing so.  Can't hurt though and will give it a go in-room. 

 

 

 

1 hour ago, 125dBmonster said:

Enclosure

 

1. Stuffing the enclosure ever tighter with absorb may not help and you could find you sacrifice the nice response you are getting at 20/35Hz now and only shift the peak further up the range if at all. General rule is sub enclosures do not use much more than enclosure damping materials as it has little effect otherwise within the low frequency band is less than half or even quarter wave length, sudden  reflective stop at end of tube though, may be an issue

 

2. Installing a baffle in the form of an angle over 3 thirds of the tube may solve the peak (resonant peak), even a circle or oval installed in the tube then turned at a 45 degree angle may help and well worth a try if all else fails

 

I have a personal belief that the 45Hz peak is being generated by resonant standing wave reaching the cone at that frequency would be an idea to do the maths on the wave length and the tube length. An easy way to find out is to experiment with another cannon w/o the end welded on.

 

The driver I am using likes to see a lot of volume behind it.  I've limited myself to the largest cabinet/tube that I am willing to put up with aesthetically but it would be nice to have an even larger enclosure.  Stuffing in the tube hopefully will trick the driver into thinking it is in a larger enclosure and will hopefully lower the tuning of the box.  I can measure the driver impedance at various levels of stuffing to figure out the right amount, at least I think I can. 

 

There is a room node at about 30Hz but it is cancelled by having the listening position exactly centred between the side walls (bonus!).  Looking at the big room node at about 43Hz it would be nice to get the tuning of the Cannons below that number but a lot of (possibly tuned) absorption on the front and back walls will also be required.

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40 minutes ago, Jventer said:

I don't know much and agree with Matt.

I have spent hours measuring (actually still am) and have learned a few things - essential to try to measure as close as possible in front of the speaker at the height it will be - on axis. If possible try different heights and distances. Not what you want to hear but do try measurements outside. 

What I do find interesting is that the canon on the right has several similarities with the ML1 on the right - in those instances I think it may be the room and not the speaker.

@almikel and @davewantsmoore

may be able to chime in.

 

 

Thanks JV.  I don't plan on testing outside but will see what I can do inside.  I've noticed that Dave has not been around much lately...good for him...but as always he would be most welcome in this thread.

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All true,

All of the speaker tuning Pros. like to get a raw speaker response as well as in room.

Is all invaluable experience as the project as a whole goes together, believe me you have a life time of tuning in that system after the fact as the need to re do a crossover or something else will happen. 

Just sitting down after the whole thing and saying it's finished may happen, but after a month or 3, the bug will bite again :) 

Enjoy Anthony, I am just watching in awe of the whole thing.

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5 minutes ago, 125dBmonster said:

Note, Enclosure size looks good only down some 7dB in the single Hz figures, nice.

 

One of my available options for avoiding digital EQ anywhere in my system and using single ended triodes top to bottom is a third bass channel to go between the Bass Cannons and the Upperbass Horn (eg. three channels 20-40Hz, 40-100Hz, 100-600Hz).  However, based on these initial measurements it looks like it may be possible to forego that third bass channel based on how well the first Cannon performs below say 40Hz.  So, no real problems down there and it may even be feasible to use a passive first order filter tilt up that falling response to 10Hz so that it goes flat.  At this stage the room problems all seem to be 40Hz and above which is right where I would have added another channel...but now I may not have to...we will see.

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33 minutes ago, acg said:

Thanks Matt.

 

One of the reasons for using the ML1's as a baseline is that I was hoping to be able to identify the room nodes and nulls.  If you compare just the green and purple lines in the graphs above (ML1 right and Bass Cannon beside it in the floor) you will notice very similar behaviour at about 40/80/120/190Hz for major peaks and 65/95/145/220Hz for major nulls.  I have just had a look at the Room simulator in REW and although it cannot sim my cathedral ceilings it is giving a result that "basically" mimics the graphs above.  The interesting thing with that tool is that you can identify the source of the particular peak or null:  most of my major peaks are caused by the length of the room (i.e. the axis in which the speakers fire) but the nulls are generally width nulls (from the side walls).  Is this good information and does it make the job of treating the room any easier?  Don't know.

 

Testing anechoically or in an acoustically "larger" environment would be nice but I am not sure exactly what I will learn by doing so.  Can't hurt though and will give it a go in-room. 

Anthony

I like your logic re the ML1's and tracking their response curves. I agree with that logic, but I am not sure if we are 100% on the right track.

I also think you are fortunate to have the ML1's - Mike should have their response curves. As far as I know it should be close to "anechoic". In other words if I understand it correctly where your response curve differ from when he measured them, it should mean it is the in room response.

I am a real novice at this and have many more questions than answers.

However, in my limited understanding, there are issues that are important:

  • the loudness of the test signal
  • on axis and off axis response
  • measurements at different distances
  • measurements at different heights

My understanding is that if you measure the various responses on axis and off axis, different distances, different heights outside or at least as neutrally as possible, then you would know the characteristics of the specific speaker/driver. That is then the baseline. My understanding is that you would like to know the characteristics of your canon and that is what I think me and Matt is trying to say.

Once you have the baseline of the speaker or driver the in room measurement differences should be the room.

When you then measure in the room the differences to that is then the room.

 

I have OCD and would at least test the theory, if the canon is to big do it with one of the ML1's :)

 

 

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1 hour ago, Jventer said:

I am a real novice at this and have many more questions than answers.

 

 

 

You are not the only one haha.

 

 

1 hour ago, Jventer said:

However, in my limited understanding, there are issues that are important:

  • the loudness of the test signal
  • on axis and off axis response
  • measurements at different distances
  • measurements at different heights

My understanding is that if you measure the various responses on axis and off axis, different distances, different heights outside or at least as neutrally as possible, then you would know the characteristics of the specific speaker/driver. That is then the baseline. My understanding is that you would like to know the characteristics of your canon and that is what I think me and Matt is trying to say.

Once you have the baseline of the speaker or driver the in room measurement differences should be the room.

When you then measure in the room the differences to that is then the room.

 

I have OCD and would at least test the theory, if the canon is to big do it with one of the ML1's :)

 

 

 

For a midrange speaker or driver I would agree with you in the need for measurements on and off axis et cetera, but the Cannons are sub 100Hz which are not directional frequencies so I would imagine that off-axis measurements are not warranted.  I may be wrong, but that is my understanding.

 

Yes, I should try to get an indication of any gremlins in the anechoic frequency response for this channel...let's see what tomorrow brings.

 

In the meantime I ran an impedance sweep on the Cannon and came up with this graph:

 

59a3e8eaa0926_FirstBassCannonImpedance.thumb.jpg.b5eefc465e50609c645b34c0ef1bd4b9.jpg

 

It's difficult to see, but 30R at resonance close to 50Hz.  Impedance varies from 6R below 20Hz and above 100Hz and the rest is resonance.  Put 8 of these together in parallel and I am looking at 3.75R resonant peak at 50Hz down to 0.75R below 20Hz and above 100Hz, which is pretty good.  By the time I have played around with stuffing the Cannon I may even be able to get that resonant peak lower in height and lower in frequency...I may even try those experiments tomorrow.

 

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In-room gated measurement of the first Bass Cannon:

 

59a4968454da6_BassCannonFirstIn-RoomGated29082017.jpg.2d4f0fbb6b7b07aa9c5db41285081395.jpg

 

I've included the soundcard and microphone calibrations in the graph as well and you can see that where the mic cal rolls off the frequency response changes (circa 20Hz).  Otherwise, it all look pretty good to me.  It is anticipated that I will low pass this channel somewhere in the 80-100Hz range.

 

Impedance measurements for various stuffings to come when I (hopefully) get a chance today.

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Impedance Testing

 

I measured the Cannon impedance with various amounts of fibreglass stuffing.  The fibreglass I am using has been cut to match the internal diameter of the Cannon and is applied as sheets of about 7cm thickness.

 

First of all with no sheets inside the Cannon.  Remember that this sounded like crap because of a feedback loop between the back plate of the Cannon and the driver...you could hear it ringing after the sound had stopped.

 

59a4c8cd1f591_BC0Sheets.thumb.jpg.77d8b8aa60e7fe4411bac5d49e9f160d.jpg

 

Would you look at that ringing at 180Hz and harmonics!  It shows up on the measurements.  Now I have something to aim at.

 

So I put in one sheet of fibreglass and ended up with the following:

 

59a4c970a2740_BC1Sheets.thumb.jpg.0197ac39882b6a6bf8f4254acdfdeaa3.jpg

 

Look how that ringing was damped with just one sheet of fibreglass against the backplate of the Cannon (light blue line).  Lets put a second piece of fibreglass in there:

 

59a4ca0eddc28_BC2Sheets.thumb.jpg.5519c403fae51218526e9399011b3023.jpg

 

Yep, 2 sheets does the trick (in green), that is better.  Try for 3 sheets now:

 

59a4ca7b00909_BC3Sheets.thumb.jpg.37e5b46de595b232b6cd6417f1ccaca6.jpg

 

Is 3 sheets (yellow line) any better?  I am not sure...there is another influence being seen now in the 100Hz+ region...the resonant peak is still coming down and is about 20R down from no stuffing in the box without significantly altering the frequency (all around 47Hz so far).  Time to put in a fourth sheet of stuffing:

 

59a4cbafe6b03_BC4Sheets.thumb.jpg.559e170d069650a370ca12933b8a7940.jpg

 

4 sheets (magenta line) has damped the resonance by another 10R and is just starting to to raise the frequency.  There is a bit more impedance at 100Hz but not really much in the scheme of things.  I've not tested to see if that is audible because that is in the crossover range.  Let's make this 5 sheets:

 

59a4cca21db06_BC5Sheets.thumb.jpg.0f29c573c4daea58d76b370144f0b929.jpg

 

This gets a little more confusing...the lower green line at resonance is with 5 sheets.  Resonant frequency is increasing without much of an impedance reduction so 5 sheets is probably at least one sheet too far.  The anomalies at 100Hz+ are more pronounced as well.  Let's just chuck a heap more stuff ing the box to see where what happens when we are grossly overdamped...10 sheets:

 

59a4cd9601410_BC10Sheets.thumb.jpg.9d0e433222d73d8559b0a18f5a1aa7b2.jpg

 

So, looking at the lower magenta line (10 sheets) the resonant frequency has markedly increased and the resonant impedance has dropped about 6R to be less than half of where we started.  Interestingly the anomalies around 100Hz+ have not markedly changed in magnitude.

 

I think that 3 or 4 sheets of stuffing against the flat backwall of the Cannon will prove to be about optimum, at least from a measurement point of view.  If I parallel 8 of these Cannons with 4 sheets of fibreglass stuffing the output transformer of the amplifier will see an impedance range of 0.8R - 4R.  I wonder if I would get different results with a different stuffing material?  Not sure.

 

So how did the frequency response change with all of these various amounts of stuffing?  Not much at all, which I suppose is to be expected when using a low output impedance SS amp as I did for this testing.  That will change with my valve amplifier with a higher output impedance, just how much I will have to test.  Here are the SPL graphs for the various amounts of stuffing (note that the red line for 5 sheets had a less controlled mic position):

 

59a4d27aaef79_FrequencyResponsevariousstuffing29082017.jpg.e0a6b37d2d9c1d841d90ad7b3c96887b.jpg

 

 

After going through all of this I really hoped that I would have been able to lower the resonant frequency of the Cannon and not just damp the resonant impedance.  Is it the type of stuffing I have used?  Would something else offer a better solution?  Any help from experienced people would be appreciated.

 

 

 

 

 

 

 

 

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