Moving on - Lots of listening going on at the same time...
I have a 29lt rear chamber on the bass horn - pretty much the smallest enclosure.
15" driver it seems typically has a volume of ~6lt. I'm a bit unclear is that is just the cone and not the basket = negligible, and the magnet = perhaps a lt?
So I have around 23lt there as is. I loaded in 5 lt, got me to 18lt.
That was close to the right vol for the conicals (17lt). All good.
Current Hornresp calc for the Hyper bass horns is 14lt if I use the design feature.
Hmm, some expanding foam (specialist stuff) in a bag is how I made a race seat once.
That could work. Bags of known vol and can be made to fit around the driver nicely and fill up the back square of the chamber too...
More thought needed.
I have a 29lt rear chamber on the bass horn - pretty much the smallest enclosure.
15" driver it seems typically has a volume of ~6lt. I'm a bit unclear is that is just the cone and not the basket = negligible, and the magnet = perhaps a lt?
So I have around 23lt there as is. I loaded in 5 lt, got me to 18lt.
That was close to the right vol for the conicals (17lt). All good.
Current Hornresp calc for the Hyper bass horns is 14lt if I use the design feature.
Hmm, some expanding foam (specialist stuff) in a bag is how I made a race seat once.
That could work. Bags of known vol and can be made to fit around the driver nicely and fill up the back square of the chamber too...
More thought needed.
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6 liter seems like a bit more volume than cone, basket and magnet structure for a 15".
I ran out of elbow macaroni trying to figure out the displacement of an 18"...
Bagged expanding foam would work to reduce volume, use the more dense type. "Great Stuff" brand available at Home Depot seems to hold up well, but it really is messy, wear gloves unless you don't mind blotchy hands for a week or two.
Yup - See previous posts... i've probably become used to it so a drop down will be interesting, I am ~5m away from the horns too.
as just a thought, you may get a better imaging by lowering the the mid-range horn. seems one should stand all the time to listen to music
6lt does seem a lot for cone but the mag is pretty big. I have not found any manufacture data so far.
Yeah an easy big filler is to cover the driver in there with polythene and then expanding foam around. With the can type as you say messy and sticks like the proverbial - you also can't do sealed bags as it needs air to set. The two pack race seat stuff sets in a sealed space. I don't really need that as I can fill in and let it foam up inside contained by polythene and then trim it to shape / reduce bit by bit.
First I need to figure out how / what to measure as maravedis said.
Yeah an easy big filler is to cover the driver in there with polythene and then expanding foam around. With the can type as you say messy and sticks like the proverbial - you also can't do sealed bags as it needs air to set. The two pack race seat stuff sets in a sealed space. I don't really need that as I can fill in and let it foam up inside contained by polythene and then trim it to shape / reduce bit by bit.
First I need to figure out how / what to measure as maravedis said.
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NP David.
Well, 2nd one knocked up:
Much less edge smoothing needed with the angle cuts.
Not finished fully but quite smooth in there for the 100 - 350Hz waveys.
Quite an effort to get done in a weekend.
Listening now - Drottningholm Baroque ensemble among others. Great church organ use on bass and DEEP bass (Tapped H handles that pf course).
Bass vocals are nice too.
Quite different to the big conicals. More detail is audible. I can turn these up more and get a nice character to tenor and bass vocals.
I'd say they integrate better with the mid horns - others have said the same thing about round Hyper or Exponential profile bass horns. How much diff round vs square actually makes I do not know - prob not much, but I like the round look.
I have back box tuning to do by measuring (more guidance needed by maravedis on that one) - should take care of an evening or two
Then I can drop the other drivers and re-time align and see how that sounds - never ends, just as it should be
Beautiful work!!!
If I am reading you right, you can submerge the bags of material in a pale of water and read the displacement. That will give you the volume of the material.
P.S., are you smoothing those on a lathe of some sort???
Bass horn chamber vols
More playing with hornresp back chamber vols and thinking what I have...
I have a total rear chamber of 30 or near 31 litres. If the driver takes up what 4/5 or 6 ltr then I have a vol of about 25 or 26 lts say.
Hornresp says that i should have 14lt... It also says that 25lt on Pi 1.0 works ok'ish. Now I do not run so close to the back wall as to get that 1.0. Changing to Pi 2.0 and I get a big step down in the region of 150Hz to 90Hz or perhaps a hump around 150 is another way to describe it...
This is pretty much what I've measured.
Dropping the chamber vol to 14lts in Hornresp cures that. Nice and flat.
So I've got to get around 11 or 12 lts of vol in there - One way to do that is to use foam and polythene. Fill it all up making a removable insert. Put that in a bag with all the air sucked out and Archimedes Eureka it. Volume known. I can cut it into pieces for various volumes to try and measure...
I'll let you know how I get on. I can see the wife giving me some interesting looks on this one
More playing with hornresp back chamber vols and thinking what I have...
I have a total rear chamber of 30 or near 31 litres. If the driver takes up what 4/5 or 6 ltr then I have a vol of about 25 or 26 lts say.
Hornresp says that i should have 14lt... It also says that 25lt on Pi 1.0 works ok'ish. Now I do not run so close to the back wall as to get that 1.0. Changing to Pi 2.0 and I get a big step down in the region of 150Hz to 90Hz or perhaps a hump around 150 is another way to describe it...
This is pretty much what I've measured.
Dropping the chamber vol to 14lts in Hornresp cures that. Nice and flat.
So I've got to get around 11 or 12 lts of vol in there - One way to do that is to use foam and polythene. Fill it all up making a removable insert. Put that in a bag with all the air sucked out and Archimedes Eureka it. Volume known. I can cut it into pieces for various volumes to try and measure...
I'll let you know how I get on. I can see the wife giving me some interesting looks on this one
Bass horn chamber vols
So I've got to get around 11 or 12 lts of vol in there - One way to do that is to use foam and polythene. Fill it all up making a removable insert. Put that in a bag with all the air sucked out and Archimedes Eureka it. Volume known. I can cut it into pieces for various volumes to try and measure...
I'll let you know how I get on. I can see the wife giving me some interesting looks on this one
Small baggies of sand work well for that
Yeah - prob less mess than expanding foam too. Will mass it all up further too.
I have some sand in the shed
I have some sand in the shed
9lt less on rear chamber
Small bags filled with all the kiln dried sand I have (from block paving drive).
Packed around - doesn't leave a lot of space but still some in the corners to go yet.
Measured and sure enough it's brought the lower bass extending down to 90Hz as modelled.
Still got a bit of a hump at about 120Hz in room at listening position.
It's not bad at +/- 5dB across the 90 to 330Hz range between crossovers.
As I ran out of sand for the other side only got 8lts reduction from 2 x 2lt coke bottles full of water and some 1 lt Tetra packs.
I def need foam to get the magic 12lt or more sand and filling the bags only half full to get more compliance for the corners.
Of course it makes the horns a lot heavier to.
So it measures flatter - How does it sound? More deep bass - more like the conicals in that respect but not the boom / colouration I think.
I still have proper tuning to do yet too of course.
So I win back the depth, gain some speed and dynamics, plus can drop the other drivers on the stands. Pretty happy.
Small bags filled with all the kiln dried sand I have (from block paving drive).
Packed around - doesn't leave a lot of space but still some in the corners to go yet.
Measured and sure enough it's brought the lower bass extending down to 90Hz as modelled.
Still got a bit of a hump at about 120Hz in room at listening position.
It's not bad at +/- 5dB across the 90 to 330Hz range between crossovers.
As I ran out of sand for the other side only got 8lts reduction from 2 x 2lt coke bottles full of water and some 1 lt Tetra packs.
I def need foam to get the magic 12lt or more sand and filling the bags only half full to get more compliance for the corners.
Of course it makes the horns a lot heavier to.
So it measures flatter - How does it sound? More deep bass - more like the conicals in that respect but not the boom / colouration I think.
I still have proper tuning to do yet too of course.
So I win back the depth, gain some speed and dynamics, plus can drop the other drivers on the stands. Pretty happy.
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Foam filler: bass horn chamber reduction
I got some fast setting expanding foam. Lined the chamber and driver with cling film and filled her up.
As one side of the foam was sealed it took overnight to set. This morning nice and set.
This evening I trimmed the foam down and cut it into 4 pieces. Putting each piece in a polythene bag and sucking the air out I then placed these in full bucket of water - slightly tilted so the water ran nicely out of the bucket spout into my container. Then I trimmed each piece to be clear of the driver and achieve the desired 3lts of volume. 4 x 3 = 12.
I wrapped each foam piece in tape so that there is no porosity.
I loaded the first 4 into the chamber and had a measure.
The foam is great as it does not add nearly 12kg to the weight of the thing.
The Result :.
In red with the new volume
Pretty flat from 100Hz to 350Hz the crossover points. Slight rises at 140 and 290 but this is in room and from the listening chair ear position! Pretty pleased with that result.
Just got the other side to do now, before I find out how they sound.
I got some fast setting expanding foam. Lined the chamber and driver with cling film and filled her up.
As one side of the foam was sealed it took overnight to set. This morning nice and set.
This evening I trimmed the foam down and cut it into 4 pieces. Putting each piece in a polythene bag and sucking the air out I then placed these in full bucket of water - slightly tilted so the water ran nicely out of the bucket spout into my container. Then I trimmed each piece to be clear of the driver and achieve the desired 3lts of volume. 4 x 3 = 12.
I wrapped each foam piece in tape so that there is no porosity.
I loaded the first 4 into the chamber and had a measure.
The foam is great as it does not add nearly 12kg to the weight of the thing.
The Result :.
In red with the new volume
Pretty flat from 100Hz to 350Hz the crossover points. Slight rises at 140 and 290 but this is in room and from the listening chair ear position! Pretty pleased with that result.
Just got the other side to do now, before I find out how they sound.
Attachments
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That is a huge improvement in sensitivity and smoothness.
Are you going to try a further reduction in chamber volume?
The poorer measurement was no vol reduction at all. So driver rattling around in 26lts or so. A whole 12 lts between them. 12" lts is a lot.
I have done the other side now and they sound great as a pair.
Quite different to no volume red.
The 2nd one does measure quite as well. Could be room or other. I'll have to swap them round and see whats what.
I have done the other side now and they sound great as a pair.
Quite different to no volume red.
The 2nd one does measure quite as well. Could be room or other. I'll have to swap them round and see whats what.
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Steve,
Has the back chamber now been reduced to about the volume of the speaker basket?
Art
Art,
No it's more than that as there is clearance around the basket / magnet and cabling. Just the basket volume would be less than 14lts by some margin I would think - I won't be wrapping the driver in a bag and vol displacement testing them though.
I'll trial more/less by 0.5lt increments of sand from here and see if I can measure.
Sounding fab now. I have all the drama and scale of the conicals but more detail and speed - presumably due to the Hyper shape which is said to be good for bass freqs.
No it's more than that as there is clearance around the basket / magnet and cabling. Just the basket volume would be less than 14lts by some margin I would think - I won't be wrapping the driver in a bag and vol displacement testing them though.
I'll trial more/less by 0.5lt increments of sand from here and see if I can measure.
Sounding fab now. I have all the drama and scale of the conicals but more detail and speed - presumably due to the Hyper shape which is said to be good for bass freqs.
Natural progression
I dropped the mid / upper and tweeters down by the prescribed amount this evening.
Makes me realise just how high up I had the horns way back with the large upper conical (the one I cut down and used the surplus edge as firewood).
Re-time aligned using Holmimpulse of course.
The tapped horn now tower over the the rest.
Much more integrated look
Moved the stacks Infront of the tapped horns - get more exciting width and instrument placement.
Sound wise - same signature sound of course. Vocals are particularly sweet though. Much listening and little tweaks coming up this weekend. At some point I'll finish and paint the bass horns... Job for spring in the sun that...
Have to lug the massive conicals round to storage too. Not going back, that's for certain.
I dropped the mid / upper and tweeters down by the prescribed amount this evening.
Makes me realise just how high up I had the horns way back with the large upper conical (the one I cut down and used the surplus edge as firewood).
Re-time aligned using Holmimpulse of course.
The tapped horn now tower over the the rest.
Much more integrated look
Moved the stacks Infront of the tapped horns - get more exciting width and instrument placement.
Sound wise - same signature sound of course. Vocals are particularly sweet though. Much listening and little tweaks coming up this weekend. At some point I'll finish and paint the bass horns... Job for spring in the sun that...
Have to lug the massive conicals round to storage too. Not going back, that's for certain.
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Vitavox S2 time
I have joined the S2 owners club - that is working fully refurbed S2's.
It's taken me a while to track down single matching ones an get refurbed - the waiting list is quite long...
Inside before.
I got home tonight to find the 2nd one back from Mike at Vitavox waiting for me. Mike has worked his magic, demag, check tolerances (all within factory spec), remag, new diaphragm etc.
I first turned some adapter rings cutting threads into compressed poly plastic.
They worked fine on light horns
Then I made some proper ones in aluminium, like the originals.
So now I can play the pair for the first time. Just plonked down with the obligatory clip leads. I'm just using a 3uF cap and the sound is electric. Vocals are so there, natural, definite.
Could be a while listening this evening...
Next up - a pair of softwood Tractrix 600Hz or even JMLC?
Here's a pic of the rig taken earlier, with the conical dispatched to storage.
I have joined the S2 owners club - that is working fully refurbed S2's.
It's taken me a while to track down single matching ones an get refurbed - the waiting list is quite long...
Inside before.
I got home tonight to find the 2nd one back from Mike at Vitavox waiting for me. Mike has worked his magic, demag, check tolerances (all within factory spec), remag, new diaphragm etc.
I first turned some adapter rings cutting threads into compressed poly plastic.
They worked fine on light horns
Then I made some proper ones in aluminium, like the originals.
So now I can play the pair for the first time. Just plonked down with the obligatory clip leads. I'm just using a 3uF cap and the sound is electric. Vocals are so there, natural, definite.
Could be a while listening this evening...
Next up - a pair of softwood Tractrix 600Hz or even JMLC?
Here's a pic of the rig taken earlier, with the conical dispatched to storage.
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So, living with them... Tonally they are tiny bit more coloured than the JBL2435Be's - I don't know how the F to describe them!
The JBL's are more accurate on simple stuff, no question . I have no doubt about that with what I shall describe as tonality.
BUT and the BUT is massive here... these are the first drivers EVER that I have heard play in the vital 1KHz and above range, that actually keep up! Ok, what do I mean by keep up?
Well, simple speed. The S2 can portray a really fast complex piece like no other driver / compression or other wise, I have ever heard to date.
This is not perhaps apparent on usual dross, but it is eluded to on vocals and on really fast string sections they just do it with an ease that NOTHING I've ever heard can. Again tonally not 100% there but speed and realism all there. I will prob just get used to the tonal aspect, or perhaps other 550 - 600HZ horns will improve even this...
I am also experimenting this evening with the Raal lazy ribbons on a simple 1st order X/O cap at 12KHz and then 15KHz to infinity... Hmmm Nice. Less is def more...
The JBL's are more accurate on simple stuff, no question . I have no doubt about that with what I shall describe as tonality.
BUT and the BUT is massive here... these are the first drivers EVER that I have heard play in the vital 1KHz and above range, that actually keep up! Ok, what do I mean by keep up?
Well, simple speed. The S2 can portray a really fast complex piece like no other driver / compression or other wise, I have ever heard to date.
This is not perhaps apparent on usual dross, but it is eluded to on vocals and on really fast string sections they just do it with an ease that NOTHING I've ever heard can. Again tonally not 100% there but speed and realism all there. I will prob just get used to the tonal aspect, or perhaps other 550 - 600HZ horns will improve even this...
I am also experimenting this evening with the Raal lazy ribbons on a simple 1st order X/O cap at 12KHz and then 15KHz to infinity... Hmmm Nice. Less is def more...
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