GoodSoundClub - Romy the Cat's Audio Site

06-25-2010

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scooter
Posts 161
Joined on 07-17-2008

Post #:	51
Post ID:	13839
Reply to:	13836

Boston wood guy

Romy,

I was reading through this post and just thought of a Boston guy you should ping regarding wood sourcing and shaping. He has hand built very good quality jazz drum shells for decades (soundwise they have no competition).

I am not sure how helpful he will be shaping non-cylindrical items but his shop is so close to you I think it is worth at least a call as he may have some ideas and may be able to source your wood. He was a one man shop so not sure if you can just drop in without calling beforehand.

http://www.eamesdrumshells.com/

Good luck,

S

06-25-2010

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Paul S
San Diego, California, USA
Posts 2,658
Joined on 10-12-2006

Post #:	52
Post ID:	13841
Reply to:	13834

Nude Descending a Staircase

Romy, Looking at your cartoon again, I wonder if you are showing manufactured trusses inside the horns?

If not, what does the shading that looks like trusses mean to show?

If so, your carpenters are either very good, very optimistic or very hungry.

Are you currently planning to do two curves per horn, or are you down to one?

If the "bottom" side that sits flat down on (or under) the existing ceiling joists/lower truss cords is more or less "triangular" in shape, then the "pitch" of the "sloped" side will change from the mouth to the throat, and the slope will not follow existing framing, apart from, perhaps, the mouth of the horn. If you plan a curve along the hypotenuse of the triangle, then the sloped side will also be a twisting curve, and I doubt it could be done with 3/4" birch ply, unless in many jagged "steps", like Duchamp's "Nude Descending a Staircase".

Unless your house is very old, the framing members are probably 12", 16" or 24" o.c., and most sheet goods for building reflect these standards. This might or might not be a consideration if you built a separate frame to receive the ply, where one might start with supports running nominally perpendicular to the joists and rafters and then add any necessary backing wherever it needed to be to reduce waste.

By far the the most dense birch ply I am aware of comes from Finland. It is resin impregnated, very very solid and strong, and it comes in MANY sizes. It is used primarily for production concrete forming. I don't know what it costs from a lumber yard these days (a lot...). Big commercial and industrial builders used to "yard-up" on this stuff when it was "cheap", and you might be able to find some someone who's slowed down and wants to get rid of some. Or, some might be available to scrounge from used forms.

Apart from the usual lumber "dealers", there are lumber "brokers". Normally, they would not talk to you; but these days, who knows. The big builders who "yard-up" on stuff like this often buy through the brokers...

Best regards,
Paul S

06-25-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	53
Post ID:	13842
Reply to:	13841

Dealing with an optimistic carpenter.

Paul S wrote:
If not, what does the shading that looks like trusses mean to show?

If so, your carpenters are either very good, very optimistic or very hungry.

Yes, this is very good question and I wonder myself if my carpenter does not tell me what I would like to hear. I pay to him a lot of money, so I wonder he have a motivation to give me good news. No, according to him it will be no house trusses inside of the horns. He even feels that it will not be necessary to do any additional reinforcement. He might be right, I do not know.

The situation is interesting. I have the typical ranch roof with attic and a cathedral room was build to a side of the building. The cathedral ceiling of the cathedral room and the ranch roof at the same level, so I have a half of the house deaths where the ranch roof is located UNDER the cathedral room roof. I mean that a section of the ranch roof is not exposed to open air and it is partially demolished (center air ducts etc…). In addition the old owner converted the part of the old ranch roof (kitchen) to cathedral ceiling with skylights. So, the idea is to completely remove the roof under roof and in the free space imbed the horns.

There is a twist however. The cathedral addition was belt by the owner himself – juts him and his father. So, HOW they built it only God knows or can predict. So, what I think is: my carpenter might be right or wrong but he work for fixed price and he might not want to add extra reinforcement. However, I might in 2 years to bring an extra bag of sand to my horn and collapse the whole house. So, I think that when my carpenter will onion the wall where the horns will be sliding into then I will invite an independent consultant (framing company or architect) and get a second opinion. That is the part of my plan.

The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

06-25-2010

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Paul S
San Diego, California, USA
Posts 2,658
Joined on 10-12-2006

Post #:	54
Post ID:	13844
Reply to:	13842

"...the wall where horns will be sliding into..."

If your wording reflects a plan to pre-fab the horns on the ground (or maybe even in a shop...), then good for you.

IMO, it would be FAR preferable to pre-fab the horns on the ground, drag them in through the double doors, winch them up (look at any old hay barn...), and pull them back into a pre-prepared open space (or spaces). Again, all those compound curves and blending of mis-matched sections will be hard enough to do if one could walk around and around the horns, with continuous access to all tools and materials, while building them. I make no secret of my particular skepticism about large "sheets-of-plywood" horns, but I am NOT being negative when I say it would be a Hell of a task - for anyone - to build (and tune...) those horns up in the space where they will reside. As for tuning, back in my savage horn days, we used to try to tune the horn profiles with model maker's "clay". I never really solved the problems I wanted to at once, but it can take very little clay in the "right place" to change the sound quite a bit, and it could also be re-worked as we went along.

If the ceiling spans under the horns have bearing walls under them, then 2 X 6 joists might hold plenty. If clear spans, you MIGHT get by with a king "rod" holding the ceiling joists up in the middle, under the ridge. Calculating allowable dead and live loads from standard UBC tables is not rocket science.

Best regards,
Paul S

06-26-2010

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Albert
Perth, Australia
Posts 8
Joined on 02-05-2010

Post #:	55
Post ID:	13845
Reply to:	13835

Possible option for fabrication

The top 3 are to scale model of the throat, mouth and length you posted above without the horn profile.

the bottom image is the equivalent flat pattern.

If you were to cut the pattern out of material and sow the sides together, add a circular frame for the throat and a triangle frame for the mouth and pull it tight you will have your horn shape with a perfect transition from round to triangle along the entire length of the horn. paint or spray this in resin and when it sets you will have a mould. Then cast your cement or plaster around this.

If you use a meterial that is non stretchy then you will get an accurate reproduction of your profile within, at a guess, +- 1cm of design profile.

I have cast things out of sand and glue and it sets very strong. Just basic wood glue sets very strong but there are of course much stronger glues available. the right glue and sand would have stronger tensile strength than cement, with comparable compressive strength. Adding some fibers to the mix would increase strength again. Jessie would know what would be best for that. any comment Jessie?

Not to mention you would end up with the surface finish you go for.

you could stand the mould on its mouth with the throat sticking up in the air and pack the sand/glue slurry around it doing it in multiple stages, working from the bottom up. i guess this way you would need something to tie each stage together much like reo bar does for cement. Alternatively you could build an outer mould to hold the mix against the inner one and cast it all in one go.

Albert

06-26-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	56
Post ID:	13846
Reply to:	13597

It is about softness, stupid.

I is funny how my listening attitude is working. While my midbass horn is not built I do not listen music on my main system. I listen in via my MiniMe (Dunlavy 3) or in my headphones at work. At my home system I do not listen but rather think how it shall sound when the playback will be up to the demands I would like it to be.

As I told I know very precisely HOW I would like my midbass to sound. It shell be exactly how it was in my old apartment but much much much softer. That bass softness is something that practically never discusses by audio people. There are many reasons for it. First, the audio people have difficulties to understand what they hear. The second is that most of horn people do not get the notable softness from their midbass. I think I heard the interesting softness from bass horns only 5 times ever. I do not know WHAT is responsible for the bass softness in horn design but I know that it might be there or might not, mostly it is not there.

So, in my wet dream I see my midbass very soft, always like a concentrated degreaser or shampoo. I do not know exactly what might be responsible in horn for this quality but I know how to recognize it and how to use it. I am sure I will hit one way of another the right acoustic pressure at right frequency but I pray that the my midbass horn turn out to be soft, hopefully “super soft”.

The caT

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

06-26-2010

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Paul S
San Diego, California, USA
Posts 2,658
Joined on 10-12-2006

Post #:	57
Post ID:	13847
Reply to:	13846

Transition Zone

Thinking of the transition from round to triangular, I go back to Jessie's fibrated "plaster" for the round profile section. To make the transition, make the narrow end of the triangle "too long", and somewhat larger inside than need be, to serve as a "transition zone". Then, leave the wider end of the round section unfinished, with the "fibers" still hanging out. You could then pull and fasten the pieces together according to horn length, pull the loose fibers into the horn and work from inside the horn to fill the inside of the "too long triangular section" until the round profile is a correct continuation of the initial flair, according to your template. The material you use for the round section would need to be more "plastic" in the generic sense than normal concrete or plaster of Paris, to preclude subsequent cracking; there are a number of materials presently available, that would fill the bill. This idea would necessarily put the transition zone at a point with a section large enough (and close enough to the big end) to get to it with hands and tools, to work it from the inside.

Best regards,
Paul S

06-26-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	58
Post ID:	13853
Reply to:	13597

Simple and brilliant jamming of horn.

Today a brilliant and insultingly simple idea come to me. I was thinking about the way jointing my sections. The horn probably will be made by 2-3 sections, plus the transition please. So, the section jointing flanges are usually made. I probably go for metal flanges and some kind poliutherine glues with a heavy bracing above, belong and across flanges Nothing exiting.

However, let see into the subject of sections a bit deeper. Why sections are problems? Because it is very difficult to make section’s joins that would have the same speed of propagating sound as it is across the section. So, what happened is, even the section joint is very good done, the joint acts a termination of transmission line and create own virtual resonating chamber. In practical term it made each section to “shake” and bit differently as termination of each section acts as own “micro mouth”. Why it is not good? Become it destroys the uniqueness of tone and create a generic tonal filth.
So, the common rule is to beef up the joints but I propose more elegant approach – to jam the horn by spreading the possible “micro mouths” vibrations. To do is very simple – slice the sections not perpendicular to the horn axis but at angle. By doing this we will not join two parallel surfaces that are perpendicular to center of horn but we join two positive and negative angles. Since pressure wave propagated in horn along the center axis, then it will “softly” enter the section join, not to mention that the join will be spread across larger surface and the sections’ “micro mouths” will be jammed.

Folks, I do not want to suck my own dick, but I feel it is a wonderful-wonderful idea.

The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

06-27-2010

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jessie.dazzle

Paris, France
Posts 456
Joined on 04-23-2006

Post #:	59
Post ID:	13854
Reply to:	13853

Resolution of a pixelated flare

Romy wrote:
"...the common rule is to beef up the joints but I propose more elegant approach – to jam the horn by spreading the possible “micro mouths” vibrations. To do is very simple – slice the sections not perpendicular to the horn axis but at angle..."

From this and from the mention of 3/4" plywood, I deduce that the "curved" walls of these horns will likely be described by a series of facets (flat planes). It is said to be okay at these frequencies; this must assume a provision that the "resolution" at which the flare will be "pixelated" is not too coarse. What is too coarse? 1 or 2 planes per meter (ppm)? As the flare is more straight twoards the throat, this figure would logically vary along the flare's length.

It might also be desirable to further randomize the resolution by varying the axial dimension of each plane beyond what is naturally suggested by an economy-based interpretation of the flare.

In some smaller French cities the "autoponts" (overpasses) are made from prefabricated flat planes of equal length; even with a long-wheelbase softly-suspended (i.e. low frequency) luxury car, these equal-length facets initiate an oscilating, bucking motion, transforming even the most luxurious cars into mechanical bulls. This would not be the case if the construction incorporated two different alternating lenghts of prefabbed road. The same logic is applied in the design of tire tread, where the size of the blocks of rubber that contact the road is varied to avoid setting up a harmonic.

Getting back to the horn; staggering the joints relative to (as seen by) the opposing wall would also seem desirable.

To answer Albert's question; how I might make the transition piece:
Assuming a faceted flare, I would make the three walls of this transition piece as a continuation of the horn, from the same 3/4" plywood, so that all sides of the triangle described by throat are tangent to a 7" circle (the triangle would be larger than the circle, tangent to the circle in 3 places); then I would cut a 7" half-circle template and use it to manually "drag in" a radius or fillet made from cheap automotive body filler (polyester resin and solids). I would run this fillet all along the intersecting corner, on out to the mouth.

jd*

How to short-circuit evolution: Enshrine mediocrity.

06-27-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	60
Post ID:	13855
Reply to:	13854

A good modeling software?

jessie.dazzle wrote:
From this and from the mention of 3/4" plywood, I deduce that the "curved" walls of these horns will likely be described by a series of facets (flat planes). It is said to be okay at these frequencies; this must assume a provision that the "resolution" at which the flare will be "pixelated" is not too coarse. What is too coarse? 1 or 2 planes per meter (ppm)? As the flare is more straight twoards the throat, this figure would logically vary along the flare's length.

It might also be desirable to further randomize the resolution by varying the axial dimension of each plane beyond what is naturally suggested by an economy-based interpretation of the flare.

I have addressed this subject above when I was telling about the circle’s chords and about their logarithmic order. Do not forget that in my case the sided will be de-synchronized , that will increase the “curve”…

Now, what is too coarse? This is very good question. I do not think that there is a definitive answer to it. Since the chords are in logarithmic order then the certain amount planes per meter will be good or bad only for certain location of curve. What I think doing is to come up with some kind of calculation that would introduce to the beginning and to the end of each chord the equal errors in relation to continues curve. I am sure that certain amount planes per meter will not be the principle as the chords will be most likely different size at different locations.
All, that I need now is good modeling software that would do it for me, I do not want to do the math manually.

The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

06-28-2010

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jessie.dazzle

Paris, France
Posts 456
Joined on 04-23-2006

Post #:	61
Post ID:	13866
Reply to:	13855

CAD software

If not for my current engagement with a race against the clock and the resulting manic situation, I'd offer to do the modeling work for you. As it is, I'm working flat out while symultaneously preparing for a very long-distance move. This situation has forced putting the construction of my own mid-bass horns on hold.

Autodesk, the parent company for various CAD software applications, offers a free 30-day trial of AutoCAD as well as just about every one of their products, amongst which, there are several NURBS and subdivision-based CAD apps. Not all are listed on the "trials" page; use the search function to find a specific application if not listed (under "All Product Trials"). It is unlikely that trial versions will allow saving your work, but you may find a way around that, especially as your main objective will likely be a printed version of the plans. Unfortunately, Autodesk's downloads require installation of their "download manager/installer".

http://usa.autodesk.com/products/free-product-trials

jd*

How to short-circuit evolution: Enshrine mediocrity.

07-06-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	62
Post ID:	13937
Reply to:	13842

A second opinion on the reframing.

I decided to bring on a table second opinion of structural engineer about my project. When my walls will be removed and all structural elements are exposed I am willing to bring on site a structural consultant who would re-evaluate my project and give to me a second opinion. After interviewing a number of structural engineers and architect I feel comfortable with this guy.

http://www.phelanengineering.com/

He is a bit expensive but I think well worth it. To wake up and to have horns on my laps would be more expensive…

The caT

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

07-13-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	63
Post ID:	13985
Reply to:	13597

The "maket" time.

I had a meeting with my carpenter and he pitched me two interesting ideas

1) Because we built ¼ of horn then the curve is relatively small. So, after do some circulations he asked me: why my triangle might not have two flat perpendicular sided and one curved side? I think that if the area of each distance from throat is the right one then it shall not be a problem.

2) After calculating the chords of horn curve he proposed that it would be much better of he built first a paper-made prototype of the horn, let say 10:1, I call it “maket” Then he feel he will be more accurately shape the chords of curve and the pattern of transition peace (BTW, we know how the transition will be done now). After we play with the maket then the full size horn will be just subject of multiplication by 10

The caT

PS: is work Maket used in English?

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

07-13-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	66
Post ID:	13989
Reply to:	13597

OK, it is this Friday!

Ok, the day is set and this Friday my carpenter and myself will be tearing down the Triangular Wall. It will be no way back and the only solution will be to plug the wall with horns. The only questionable subject is if to put a building permit from my town to do this work. This is controversial. The work will not be exposed to outside and might go away with no permit. From additional perspective it will affect the framing of the building. I do not mind to get a permit but I have no idea what to request for. The permits are given for specific work and they are itemized. I am very much sure that not one got a permit for installation of bass horns. Did anybody have any experience with requesting of permit to do non-standard work?

The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

07-13-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	67
Post ID:	13990
Reply to:	13989

How to predict Back Chamber.

This is a complicated subject.

While building the horn I would need to know what the size of back chamber to make. Usually the initial size of driver diameter plus two depth works very nice. It makes big chamber that eventually might be minimized to tune the resonance frequency properly. I do not have the Jessie’s luxury to build metal, high-precision, calibrate back chamber. My back chamber will be simpler and I will be using acoustic foam to minimize the side tuning the resonance frequency to the horn rate.

http://www.romythecat.com/Forums/ShowPost.aspx?postID=2991#2991

There is however a kink in my situation. I really would like do not open and close the Back Chamber and do not staff it with filler while the horn in attic. I would like to do it while the horn at ground level BEFORE the horn will be lifted up and slide into the wall. My horn is 1.4 size and after it will be installed it will “see” the ceiling of my cathedral room. It means that the volume of the air from my cathedral ceiling pitch will be added to the mass of the air in the bell of the horn mouth, changing the rate of throat reactance and consequentially driving the resonance frequency away.

So, there are 3 options to deal with it.

1) Set the resonance frequency after the horn are lifted up and installed. I do not want to do it – too little room will be left in attic between the horns and large center air unit.

2) Make a maquette (thanks coops) measure that deviation of load between floor and cathedral ceiling and to presume that the delta will be the same for large horn. I do not want to do it as well as I feel it will be very inaccurately. The large horn will behave very different.

3) Make a guess. Assume that cathedral ceiling changes let say 5Hz and to make the necessary pre-corrections.

The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

07-13-2010

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Paul S
San Diego, California, USA
Posts 2,658
Joined on 10-12-2006

Post #:	68
Post ID:	13991
Reply to:	13990

Smart, Simple and Direct

Glad to hear you'll be building the horns on the ground, after all. It really is the best way, for so many reasons, as you will see.

Romy, if your carpenter knows what he is doing, then I recommend you do not alert local building officials. They will have their own view of what you are doing, no matter what you tell them, and they may well require formal "plans" and "engineering", which will seriously increase your costs and add delays while you get it done to their satisfaction. Then they will add their own "fees" and inspection costs, and they don't work cheap. It can really add up in terms of time and money, not to mention the very real possibility that they'll throw you a "curveball" at some point.

Regarding the back-chambers, how about making "temporary" access holes? Maybe something like an attic scuttle, even if you can only get your head and shoulders up there while working off a ladder. You will be SO glad over time that you left yourself a way to adjust this as you develop the system as a whole, to work in the new space. Of course, it may even require re-tweaking when you bring in ULF, which I ass-u-me you will do, at some point.

Best regards,
Paul S

07-14-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	69
Post ID:	13993
Reply to:	13832

The wood source is found

Romy the Cat wrote:
Where to buy inexpensive birch plywood? There are American, Canadian, Russian and Chinese birch plywood. I would like to go with Russian – much better quality, but it got pricy nowadays. I would like to pay for ¾ sheets of 4 by 8 no more than $40-$45 in case of mass buy. If any of you know in your jurisdictions a sores to get cheap Baltic birch then let me know – I might arrange shipping. Still, I would like to get the plywood in New England and to pick up it locally

Ok, the source for my Baltic Birch is found. It is in NH (means not sales tax), it is just 30 min from my house (I can pick it up). They have in stock “clear face” Baltic Birch of ¾ and at the price that is more or less reasonable.

http://www.pjclbr.com/

I think I will be loading with Russian Birch on Saturday. If everything will be as I planed then next week the project will be on it’s way.

The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

07-16-2010

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Paul S
San Diego, California, USA
Posts 2,658
Joined on 10-12-2006

Post #:	71
Post ID:	14001
Reply to:	14000

Dust to Dust

Romy. if you have not already done so, I strongly recommend you cover everything in the house with cheap plastic, because of the DUST that inevitably gets EVERYWHERE unless the workers make a containment "tent", which would be cruel and unusual punishment this time of year, since working inside one is like working in a steam bath. It is also a good idea to cover all heat/AC inlets and outlets, or the dust will begin anew when you finally fire up the FAU. For the same reason, try to keep the doors to "your" part of the house closed while they are working, if possible. They might be able to make a plastic "partition" to section off at least part of the house.

Best regards,
Paul S

07-16-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	72
Post ID:	14002
Reply to:	14000

The day is over.... now there is no way back.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

07-17-2010

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wvdave
wv
Posts 4
Joined on 05-18-2010

Post #:	74
Post ID:	14004
Reply to:	14002

Interesting space

Very nice looking attic space to place horns. Don't remember if you posted the size of the horns' mouths,but if there is room i'd put an access hatch in there somewhere. Secure all those wires out of the way. And I would get rid of that fiberglass insulation and replace it w/the polyester stuff around now or better w/styrofoam sheets between the roof rafters-otherwise, your horns will be subject to large temperature variations. You may even want to arrange things so as to be able to control the climate around the horns. But, you and your carpenter have probably been over all that So far, so good with a very cool project.

Age Quod Agis

07-17-2010

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Romy the Cat

Boston, MA
Posts 10,160
Joined on 05-28-2004

Post #:	75
Post ID:	14006
Reply to:	14004

The opened up space.

Paul, I do not care about dusts. I coved what need to be coved about the rest…. I do not care. The building of midbass - is a final stage of my moving and ….unpacking. So, I did not put any “vulnerable” furniture in the house as I knew that the midbass horn is coming. Also, there is not a lot of dust. All that we do truly dirty was cutting the triangle wall, the rest is relatively clean.

Zako, sorry, I am not well-familiar with US’s pop-capture and I do not know what this quotation would mean.

Wvdave, I have posted the different numbers before. Now as the wall is out and the space is well-expose we are getting the final measurements and finalize the design in accordance to the space we have available. The space is complicated – two roofs collide but I think we will be able to use the curvature the shapes two roofs to slide the horns inside. The basic geometry of the horns and the most important the coupling to attic space needs to be figured out first. Then we will nail doe the best way to load insulation, reroute the power and security cables, the center air ducks and so on. I will post later on a picture of the opened space you will see what I deal with.

The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

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»	New	Practical Guide for Back Chambers Tuning...	Back chamber’s cost-benefit....	Horn-Loaded Speakers Forum	5	76051	10-21-2006
»	New	Superbly interesting effect: Suspended decoupled floor ..	Superbly interesting effect: Suspended decoupled floor ...	Playback Listening Forum	0	18119	10-08-2010
»	New	Midbass impedance bumps -- why and what to do?..	You need to stop deceive yourself....	Horn-Loaded Speakers Forum	18	194276	10-21-2010
»	New	Mystery of bass horn calibration: Radiating Surface Dee..	Mystery of bass horn calibration: Radiating Surface Dee...	Horn-Loaded Speakers Forum	0	17302	02-03-2011
»	New	Impulse response, short notes and midbass horns...	A possible solution to better impulse?...	Horn-Loaded Speakers Forum	14	128440	06-13-2011
»	New	My new “New” listening room, 2024..	That is not enough efforts in this direction....	Audio Discussions Forum	31	18397	05-08-2024

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