Romy the Cat wrote:

I sometimes visit an Australian site and familiarize myself with progress of “acg” who it trying to build Macondo like acoustic system.    http://www.stereo.net.au/forums/index.php/topic/75784-deep-end-diy-my-first-speaker-project    A few weeks ago I requested at the site and answered a few open questions. I do not think I argued with anybody or was involved in any controversial topics. In fact it looks like the member in there were appreciative of my contribution. Well, for whatever reasons I got banned from the sites. My initial sentiment was why the hell they doing it? Well, thinking for another 5 seconds I realized that my initial reasoning was very accurate and in fact did not change over the last good 20 years: audio people generally and whose who elect themselves in administrative position particularly are fucking idiots. It is not a big deal. The stereo.net.au might joint a long list of the audio sites that do not deserve my presents and they can die this their little pathetic secret. Nevertheless, the efforts of the “acg” has nothing to do with the idiocy of the site administrators and sine I discovered that “acg” asked me direct quite intelligent questions and since I can’t answer them at the Australian site I decided to make the Australian’s Macondo discussion available at my site.

Romy the Cat wrote:

Well, acg, I am not wild about your idea of the curved frame, primary on the reason of esthetics but it is your speaker not mine and you shall do whatever pleases you. A few mandatory things that I would like to mention and I think you need to factor it into your design.   1) The Macondo channels shall form a curve or parabola with your listening position being in center of a curve. I have illustrated it years back at the following image: http://www.goodsoundclub.com/Site_Images/MacondoFrame31.jpg I would very much discourage you to angle the horns and many foolish people do, juts align the channels. To do so you would need to have a provision to move the channels closer and further. Your current design does not allow you to do it. You might avoid to move the channels closer and further if you calculate and factor in the curvature and listening distance into the initials destine of the channel arms.

Romy the Cat wrote:

2) During the alignment of the channels you do not need to drop a plumb bob from the horn throat or the driver exit but from the location of the driver diaphragm. The S2 have diaphragm on the back, so you overshooting in your design good 5-6 inches

Romy the Cat wrote:

3) The time integration of MF and Upperbass is tricky. You can calculate where the Fane diaphragm is, where the S2 diaphragm is and they pretty much not on a curve but on direct vertical line. The precession of that calculation is kind of not important as Fane is not flat and has dome depth of the diaphragm. So, doing subjective assessments of the integration benefits I realized that all that you need to do between those channels is putting the MF atop of the point of max amplitude of upperbass.  500Hz has a wavelength of around 2.2 feet, 1000Hz is around 1.1feet. With such a long wave you will have a very high precision alignment if you align them approximately by geometry and then lock acoustically by summation of amplitude measurement. I did exactly this and then, after I knew the final position of my MF driver I order a fixed, well calculated arm for my tweeter. In my case I make my MF drive to position atop of positioning table with .01mm accuracy. I personally do not feel it is the best idea and I would rather advise to make HF being able to be .01mm positioned by MF would be fine with 1-2mm. You would not need a machinist position table for it and some kind of general slider would be fine.

Romy the Cat wrote:

4) You do want to lock the location of the Midbass horn with the frame and it will be moving side to side. A horn that angles breaks time alignment.

Romy the Cat wrote:

PS: I won’t be reading too much at the Australian site not to mention that I can’t see the pictures. So, if you need anything then ask here.

kodomo wrote:

Great project! I have a similar project going on. Your frame ideas are looking beautiful, however I decided to take a more utilitarian road. I can adjust all my channels in horizontal or vertical axis. I am finishing my crossovers as of these days, and they are 6db except for the bass towers which are 12db. I had to do impedance equalisation to be able to use the 6db filters to work. Months and months of listening and measuring for me and even after everything is finished. The channel attenuation according to my space will continue for a few months more until I am fully satisfied... You can see my project here: http://tempuri.org/tempuri.html May I suggest using impulse response when aligning the relative drivers. This is the most accurate way of doing it as far as I know. You need a sound card with at least two inputs, and a microphone. REW is free and is able to help you with this. If you need further information on how to do it, I would try and explain it in more detail to you.   I would also look at acoustics of your space. I am an interior architect and studied acoustics. I have also worked in music studios and am a musician who owns a private music studio as well. Please do not skip on spatial acoustics, they have as much effect as any part of your signal chain. I have made some acoustic panels according to my needs too. They are multi-purpose and effective panels. The outer shell is 1d diffusor that works up to 4500hz. I have special fabric behind it and then 10cm of 100kg/m3 mineral fibre, which is quite effective (about 1 sabin from 150hz and upwards) down to lower cutoff of my upperbass 110hz horn. If you can put spacers in between the wall and the panel you can bring it further down to about 80-100hz effectively. Believe me, if people tell you they can effect 20-40hz with their panels, it is either to a very low effect, or an incredibly thick panel that is alos strategically placed or they don't know what they are talking about. Some panels with resonators in perfect spots may have an effect lower than 80hz, if there are enough of them in your space. Anyway, here are the panels I built. They are known as BAD panels commercially. I need 12 of these panels, plus 4 thicker panels in my space. I also needed about 12 of 60x60cm quadratic 3d diffusors. Oh and yes I am a bachelor You can easily find the ideal amount of absorption you need in your space to get the right amount of reverberation. This will result in units of sabin. Only after choosing the right treatments, then you can start treating the first and second reflection points. Do not forget the ceiling. I also suggest appropiate quadratic diffusors if you are far enough from the walls and ceiling to be placed around your seating position.

Romy the Cat wrote:

Here I share some thoughts about what you have shown. I will share only critical and warning thoughts not because I have nothing but critiques. All nessesary compliments for your planning come as a default and I do not think you posted it here to hear salutations but you rather prefer to hear warning from the people who have done it. Jessie, if you are around there then you would be a good person to comment about your experience regarding this project as you have done something similar. Anyhow here are some of my comments in no particular order.    1)      I do not know why, and I never thought about it unit I have done my project but I am very sensitive to visual aspect of what is located juts behind the Macondo frame. As I look at the Macondo horns fixture with the tweeter projects to the main frame it look sand feels very elegant and symmetrical. For some reasons I do not like to see behind the frame anything that screw up the elegance and symmetry. This is why I do not like to put Milqs amplifiers behind the Macondo frame. I did try is multiple times and it did not feel good to me. I personally much prefer when the amps not behind the frame but slightly on the side of the frame. It just makes to me the whole playback configuration more balanced. Do not forget that with Macondo configuration you will have the speaker’s stage at ~14-16 feet minimal. With upper-bass horns of 36” you will have a LOT of empty space between the speakers… Saying it I need to admit that it is just me and your mileage might wary, it is not to mention that your amps is located very low and you might not even see it,

Romy the Cat wrote:

2)      I do not buy the idea of tube woofers, I never did it with the guy from Mexico and I still do not like it. First of all the harnesses that you depicted will not work. This will be very heavy and you will need some kind of heavy duty vertical poll to hold the whole stack together. The ability to slide the individual woofers is a great thing but why not to do it in rectangular boxes? If you are planning to use the woofers that I used then you would need at least 1” foam in there – you will not have space in those small 10” tubes. If I did it and to have the objective to time-slide the woofers I would make 4 rectangular sections with 2 drivers each and would make the front baffle let say 5 degree angle. They I would be able to fulfill any configuration by sliding and rotating an individual section. Well, I do think that to have 4 dual driver section with straight baffles will be fine as well…

1. There is less work for me in the steel construction.  This Macondo/Melquiades build has been going over two years now and I really want some results.  With the wood box I would be compelled to build them and finish them and paint them which is a lot of time that I can put elsewhere.  With the steel construction I have them laser cut, a guy I know will weld them for me (my welding is amateur at best) and I will have them powdercoated by someone else and the colour match will be perfect with the power supply and amplifier cases.  All I have to do is drill and tap some holes in steel which I can do over the course of a weekend. 
2. I have designed the 2 driver wood boxes and when I stack them and put them next to my horn stack in CAD they are just not as pretty as the steel tubes and actually detract from the aesthetics in my opinion.  The main problem is the width of the front baffle and the long straight sides that seem to not compliment the horns.  They are different to your woofer towers Romy in that the drivers have no vertical separation between them and I am limited to a 1m (40") depth so the baffle needs to be wider than yours.  My wood version looks more bloated and oversized by comparison.

Romy the Cat wrote:

3)      A missing channel. If you have your playback in a small room and you will be lucky to have your upper bass horns at very active spot of your room then you will be fine with the configuration you shown. I had it what I live in Boston and my upper bass horns work very comfortable at 95 Hz and they were in active room zones. If your room is larger and if the upper bass horns are not at hot spot then you will have 130Hz of it this upper bass horns. If you use my woofer then your cross them over 100Hz will be a bit problematic. My woofers are very interesting. If you use it at 100Hz then they are more at crap side. You need to cross them much lower. Then you begin to multiply them. As you pile 4, 5 or 8 of them you have a substantially more interesting results. 8 of them you will be able to use even at 100Hz but only in small room and only with very lightly loaded amplification. The woofers have own signature but very pleasurable and much dominated by second harmonics. I tend to love. I can hear instantly that my woofers are in playback and I agree that they are “coloration” but this “coloration” agrees with me. So, you might consider to have a dedicated midbass channels but to do it you your to take your room and your spear placement into configuration. You do not know it yet and then you do not k now the crossovers, gain and the OPT from app you might need. So do not rush as at this point not everything might be predicated. What I would adviser is to buy 2 of my woofer and play car audio game with them, trust me, it is very educational.

anthony wrote:

I have designed the 2 driver wood boxes and when I stack them and put them next to my horn stack in CAD they are just not as pretty as the steel tubes and actually detract from the aesthetics in my opinion.  The main problem is the width of the front baffle and the long straight sides that seem to not compliment the horns.  They are different to your woofer towers Romy in that the drivers have no vertical separation between them and I am limited to a 1m (40") depth so the baffle needs to be wider than yours.  My wood version looks more bloated and oversized by comparison.

oxric wrote:

Hi Anthony, I am amazed by the work you have accomplished so far and love your stands and horns stacks. Two comments though in term of overall esthetics although I realise that having spent so much time on this it may be too late to make changes. I would not have the amplifier hidden behind the main pillar supporting the horns. It distracts from the beautiful lines of horns and support. In addition, I think, if only in theory, to completely isolate your amplifiers and power supplies from your horns and drivers, would be a good thing. I appreciate that you do reduce cable lengths by doing so but am inclined to think that by positioning your amplifiers along side walls, the benefits outweigh these other disadvantages. Secondly, the bass cannons. Sadurni Acoustics does something very similar but I think this contraption with the several separate individual bass enclosures is an unecessary distraction from the horns and support. I would try to use a bass tower, maybe two modules of 4 drivers each, and still make provision for alignment of these drivers within its design. Please ignore comments at leisure as your project is quite remarkable as it is. rgds Rakesh

anthony wrote:

This is excellent information Romy.  I have been worried about crossing the woofers at 100Hz and would be much happier if I was able to cross them lower.  We will see how everything integrates into the room and if I do need the extra channel for mid-bass.  I have allowed for it in the design so far, but just have not actually designed such a channel.

kodomo wrote:

Just a reminder about the room acoustics. You are talking about bass frequencies which are as dependent to the room as the speaker! Before installing your speakers into your room, calculate the nodes and the amount of absorption you need to cover the room from the dimensions of your room and use specific acoustic treatment for that. An appropriate rt60 and a balanced room response creates a very nice listening. Even though this is a horn system, you will be still listening to your room and not just the horns.

kodomo wrote:

Hey Anthony, Your project is going on track (and looks like a very good track)!   Just a reminder about the room acoustics. You are talking about bass frequencies which are as dependent to the room as the speaker! Before installing your speakers into your room, calculate the nodes and the amount of absorption you need to cover the room from the dimensions of your room and use specific acoustic treatment for that. An appropriate rt60 and a balanced room response creates a very nice listening. Even though this is a horn system, you will be still listening to your room and not just the horns.   Treat the problematic bass regions first, this means all the corners you can cover. You can also build a front wall or a back wall diffuser or both from Tim Perry's plans. Remember the distance from the diffusers are very important for even response. So the depth you choose for your wells in your diffusers will dictate the frequency they will cover and the minimum distance they have to be from the listener. Then install your speakers, remeasure and then address your problems again, starting with the first reflection points. When you have the specific place for your speakers, the first and the second reflection points will be known. I suggest treating not only walls, but also the ceiling in the first and second reflection points. Remember this is not a recording room but a listening environment, so you are aiming to get closer to a non-environment room (not completely) Here are the links for diffusers and absorbers, I suggest you to build http://arqen.com/sound-diffusers/ http://arqen.com/bass-traps-101/placement-guide/ I can also share my diffuser/absorber panels plans but they are for my specific room, you can however use the idea.

Romy the Cat wrote:

Kodomo, I do not say it is unnecessary but I do not think it is possible for Anthony at this point. The calculating of testing the nodes is questionable task and I would advise do not do it. Anybody who undertake the project as Anthony does had some kind of playback in the room before and knows the room basic problems and strengths. To think now about absorption, diffusion and the rest of the game is completely pointless. I think people shall address the problem in order the problems arrive. As peoples has a basic Macondo rendered in the room he will play with it to imbedding it in his specific room. At that time he will be changing the crossovers, move the speakers, play with acoustic treatment. There is no k now to me was how a person can model it. The whole idea to play with the speakers in your room is to teach yourself about the speakers and the room. So, I do advise do not invest into any acoustic treatment ... unless you feel/hear a need for the acoustic treatment.

Romy the Cat wrote:

BTW, I was kind of saying it many times in past but I think it high possible that it was no lost in translation. Anthony, if you are trying to implement with your version of Milq the same multi-amping with line level filters at input then make sure that you will have output stage of your frond end the will be able to drive all of it. Most of the preamps will not have current to do so and your filters will be not operating properly due to too high front-end output impedance. So, think forward…

manisandher wrote:

I hope you'll be open to having visitors once it's all up and running. I'd love to come over if I happen to find myself Downunder any time. Mani.

anthony wrote:

You can see the little 2-way standmounts that I am currently listening to behind which are the 'wings' onto which I will build the DSET.

anthony wrote:

I've been in a conundrum with the preamplifier.  In the past I have never been happy with anything that I have tried and as a result have direct connected my dac to amplifier, but I do love my FM and find that if I have to change cables that I just stay listening to the source that is playing and don't listen to the other.  In desperation I managed to find a second hand Placette Active Linestage but when it arrived I was quite underwhelmed by the hit to dynamics and some problems with HF in particular.  As you may recall, the Placette does not have feet of its own (at least mine has no feet) and since I recently completed the audio rack I plugged the Placette back in and sat it on a towel and it does sound much more capable than I originally thought.  I am hoping that once I get it on one of my anti-vibration platforms that I will hear in it enough potential to persist with it and try to make it work better.  It is quite surprising how much difference the rack with damped shelves and the towel to further decouple it has made to the sound.

Jorge wrote:

Hello Anthony, I did experiment with metal tubes for bass in a sealed configuration as you are planning. The weight of them, even made out of thinner than you would like steel, is prohibitive.  If you make them out of aluminum pipe, then it could be better, but still pretty heavy.  The stack will probably be unstable and shakey. Do not try to place them one further than the other, or not perfectly aligned,  the bass will distort terribly, cancellations will cause a mess of the sound, remember they will be playing the exact same frequency. (I did that and learned from the experience)

Jorge wrote:

Of course they look much better than the boxes with the added benefit of difussion of sound waves hitting on it, against the reflection from a flat side panel of a box, so there are a lot of considerations you must make. The bass modules I am using now are actually a form of concentric tapped horns using a long excursion 8 inch woofer servocontrolled by a powerfull class D amp.  These are a redesign from the original, longer, passive bass modules which sported a 6.5 inch woofer.   I am using one per side now.

Jorge wrote:

Hello Anthony, The bass modules I am using now are actually a form of concentric tapped horns using a long excursion 8 inch woofer servocontrolled by a powerfull class D amp.  These are a redesign from the original, longer, passive bass modules which sported a 6.5 inch woofer.   I am using one per side now.