While my R&E deal on hold (had to close tomorrow but proponed) I n order to keep some sanity I was playing with idea of listening room arrangement. As I told the room has a number of very cool properties that I fall in love to from start. One of them is ability deal NATURALLY with first reflections. The room has cathedral clearing and carpet floor – so the top and bottom first reflections are well attenuated. Then take a look at the most annoying side first reflections. The room uses my favorite long-wall configuration and at the same time it has naturally killed side first reflections. That is one of many little secrets of my current room. The NATURALLY killed side first reflections are very important and this success is something that I was looking to capitalize in my new room. Almond many houses that I have seen this was the ONLY house where the concept of long-wall positioning  with no side- reflections might be implement as is with not room modification.

The distance between the speakers is 15-16 feet and the distance to the sweat spot might be anything up to 17 feet in my estimation, though I think it will go for 10-12 feet. From my perspective it set a perfect opportunity. I am still debating what to put the equipment rack at the “A “position of the “B” position (taking down that little dividing wall) but it would not be another subject…

I think I found someone who might be personally interested participating in  my 40Hz horn project. 

http://www.wmos.org/artists08/kostick.php

http://web.mac.com/jjkostick/iWeb/jjkostick/Welcome.html

http://www.swarthmore.edu/NatSci/math_stat/people_alumni_janek.html

I think if it goes through then they will be able the pictures on this web site with something REALLY exiting….

A few weeks back a local industry-reviewer visited me. We were listening music, spoke about audio and discussed the prices of real-estate in context of audio objectives. The guy lives in south New Hampshire, in a large house and when I told him how much I pay for my apartment in Boston’s Back Bay he was insulted . I got my mortgage papers through last week and it look that the cash default burning rate (premium + tax + insurance) of my new suburb house will be juts $40 more then what I pay for my apartment. After putting all of it together my NH guest was leaving and told “I have the city live. Boston, you can have it.”

Ironically this is the very same attitude that I have developed since I begun the fight for this new home of might. My closing had to be 3 days back but was postponed because some external reasons. Not it will be (it hope) sometime in March and live in empty apartment, with all my shit is packed, feeding myself with a new huge masochistic hate to city life. Two day back I decided to go for a little Harvard production of “Tosca”. After spinning in Cambridge (the city I hate since I moved to Massachusetts) for an hour in search of parking I was so pissed that I decided do not go to the theater anymore and my mood was completely screwed.

Perhaps it is my unreasonably delayed R&E deal or whatever else reasons but I nowadays truly despite the city live. The city put too much demands for me to comply with city living but I do not think that get back any equitable reimburse for this privilege. Perhaps I am getting older but buy those “demands” begin to annoy me. I wonder what would be the next: to buy a track and to register republican?

Romy wrote (in the "It’s mad, mad, mad... electricity." thread):

"...I might not have enough power in new room for my woofer towers and it would force to use class A/B SS amp..."

You've mentioned on more than one occasion how much you love what your woofer towers do. You've also mentioned that once moved to the new house, before deciding whether or not to build the mid-bass horns, you'll set up the system in its current state and spend time educating yourself as to the possibilities offered by this new room.

Assuming you go ahead with the mid-bass horn project:

If you decide to run the woofer towers along with the mid-bass horns, it is logical to assume they'll produce much of the range produced by these new horns.

What would be your motivation for running two sources of mid-bass?

Do you anticipate having to use the woofer towers to augment the output of the mid-bass horns in order to properly load the room?

Would the towers be a means of bringing perceived origin of mid-bass around to the space in front of the listener?

If this is about room loading, with lower-bass enclosures in the picture you might feel differently. Since you've alluded to the possibility of pursuing the lowest octave, and since you're buying the perfect lower-bass enclosure/back chamber (just mount some 18-inchers in boxes open via the floor to the basement... Yes, a sealed basement), its too easy; you have no choice. However, using civilized crossovers, some mid-bass reinforcement of the 18" variety will be inevitable; this, in my experience has not been a bad thing:

With mid-bass horns still not in use, the obvious weak zone in my system is centered on the 80-160Hz octave (see note at end). This void does not seem so pronounced as to require more than the work of a single pair of horns. The lower-bass enclosures are cut off on the high end at 60Hz, 6dB/octave, and though only very lightly solicited, listening without them does leave the kind of void I would not expect to fill using a single pair of horns.

jd*

Note at end:
I've replaced the drivers in the upper-bass horns for 8 Ohm versions of the same driver, curing the slightly anemic tendency in that range; I mention it here for the clarity of readers following the thread where that issue was discussed.

jessie.dazzle wrote:

Assuming you go ahead with the mid-bass horn project: If you decide to run the woofer towers along with the mid-bass horns, it is logical to assume they'll produce much of the range produced by these new horns.

I do not know how accurate it will be. I will need to look what my midbass horn will do and then to learn how much I need to compliment them with lower end. There is a remote possibility that my current bass arrays will be less effective if I use them at sub 40Hz and perhaps with sharper filter. It all depends how much bass my room would need. If it would need 300W-500W of power then I see no reason to drive my very fine and fancy array and might got for 4 Aura 1801 drivers that I have in my storage. Again, my arrays are refined tool not the high-power brutal force tool. They do a phenomenal bass (the guy from “Enjoy the Music” was not kidding – the bass is exceptional) but it is ONLY in context of my relatively small room where amp is in A1 and exertions is very moderate.

jessie.dazzle wrote:

What would be your motivation for running two sources of mid-bass?

I do not know if I will. I would need to know what my mid-bass do. Do not forget that I have a LOT of mid-upper-bass tool in disposal. I have 6dB extra in my current upper-bass horn and I have high-pas my injection channel at 120Hz. I might let it all to go….

jessie.dazzle wrote:

Do you anticipate having to use the woofer towers to augment the output of the mid-bass horns in order to properly load the room?

Yes, sure, the crossover point and the low-pass slope of woofer will be in respect with what mid-bass horns would do. at this point it is absolutely imposable to speculate on it.

jessie.dazzle wrote:

Would the towers be a means of bringing perceived origin of mid-bass around to the space in front of the listener?

Good question. I sincerely hope that it will be the job of upper-bass channel and the Injection Channels. Ideally I feel that if I use 40 Hz-150Hz midbass horns then I would raise the crossover on upper-bass channel to let say 200Hz. It would be great for upper-bass quality BUT it might be no enough to maintain the since of defectively from midbass as the ahs will be behind. I hope (juts hope) that because I am planning do not let the mid-bass to shot directly to the listening position then the true location of the midbass horns will be mercy and not too visible. Anyhow, I will be dropping the crossover of the upper-bass to set the bass’s source properly. I hope I will not need to go to low to do it. Surely, it all will be observable only practically on the field.

jessie.dazzle wrote:

If this is about room loading, with lower-bass enclosures in the picture you might feel differently. Since you've alluded to the possibility of pursuing the lowest octave, and since you're buying the perfect lower-bass enclosure/back chamber (just mount some 18-inchers in boxes open via the floor to the basement... Yes, a sealed basement), its too easy; you have no choice. However, using civilized crossovers, some mid-bass reinforcement of the 18" variety will be inevitable; this, in my experience has not been a bad thing:

I do not know. I see no problem if a time-aligned bass channel with first order and long tail runts into midbass. I still would like however do not do it if I have a change do not do it.

jessie.dazzle wrote:

With mid-bass horns still not in use, the obvious weak zone in my system is centered on the 80-160Hz octave (see note at end). This void does not seem so pronounced as to require more than the work of a single pair of horns. The lower-bass enclosures are cut off on the high end at 60Hz, 6dB/octave, and though only very lightly solicited, listening without them does leave the kind of void I would not expect to fill using a single pair of horns.

Why don’t you raise the crossover point on your midbass-horn letting it to take over more in upper-bass region? Are your midbass and upper-bass channels in phase acoustically? Can you post in your thread the separate sweeps at the same volume level of 1) upper-bass 2) midbass 3) combined midbass and upper-bass in phase. 3) combined midbass and upper-bass out of phase.

jessie.dazzle wrote:

6dB extra? Relative to what?

Relative to the reference level of my MF channels. Look at the Chenal “B” of the the amp's schematics:

http://www.romythecat.com/Site_Images/6-Chennal_Melquiades_DSET_Amplifier_Rev3.jpg

You see at the channel’s input 30K by 12.1K voltage divider. His attenuates my Upperbass for ~6dB in relation to the rest of my channels. The bass channels is the reference one – it runs wide open a full gain. The rest channels are juts referenced to the bass.

jessie.dazzle wrote:

I think you may have misunderstood; the mid-bass horns are still under construction. I was describing the void I hear in their absence. The plan has always been to let the mid-bass horns run from 90 to around 240Hz. Once they are up and running, I will of course try pushing the low end lower, but I'm not "officially" counting on them for anything under 90Hz.

I see, I thought that you have the mid-bass up and running. What you might do it to use firs order on your bass and to move crossover point upper a bit. I do not know what kind bass modules you use and how good they are in upperbass. I still do not know why you have weakness in 80-160Hz octave. Your upperbass shall cover it perfectly fine. Can you post sweep of your upperbass alone with no crossover. Actually I would need 4 sweeps if you do not mind.

1)      Regular slow sweep were 20-20000 is passed within 15-20 seconds from horn default position

2)      Regular vibrating sweep were 20-20000 is passed within 10 seconds

3)      Regular slow sweep were 20-20000 is passed within 15-20 seconds but from different location, from another perpendicular wall

4)      Regular slow sweep with your other channels attached electrically but the horn are plugged and do not radiate sound.

I do think that you have some kind of bug as I feel that your upperbass shall not have the 80-160Hz problem.

jessie.dazzle wrote:

"Horn default position"; do you mean from the listening position? "Perpendicular wall"; please define relative to the firing axis.

"Horn default position" – the position where it will be sitting normally in the system

"Perpendicular wall" – move the horn to another side of the room, preferably to another perpendicular wall.

In all cases - place microphone in only one position – at your listening position. Move hone but do not move microphone. If you microphone is directional (as most of the microphones are) then just turn it toward the horn.

Since in a couple of week I will be diving into the subject of constriction of my own listening room I do pay attention of what other talks/do about their rooms. Here is the Mike Malinowski’s room trip:

http://www.6moons.com/audioreviews/theroom/1.html

He built the room for Wilson Alexandria and as far I can tell the room is dedicated. Not everything that Mike did I like but I think it a good reading all together.

Romy the Cat wrote:

I was thinking about the throat of my hypothetic midbass horn. This is complex, controversial and it has pretty much no answer, at least in the formeat I ask it. I will share my thoughts with you. Let pretend that I went for exponential midbass profile, perhaps with a slight hyperbolic dent. Let look a very preliminary numbers for spherical horns. From the diameter of spherical it is simple to get area of circle and to convert it to any rectangular format. Also, if I would like to add to my exponential profile any hyperbolic depression (and most likely I would) then it would make the horn longer, let say 15% longer for a sane level of “hyperbolicizm”. Throat diameter  Type (Hz)  Length  Mouth diameter  4” , 10.2 cm, 81.7 sq cm  50  3m / 9' 10"  1.6m /5' 3"  4” , 10.2 cm, 81.7 sq cm  40  4.03 m / 13' 3"  1.95m / 6' 4.8"  6” , 15.2cm, 181 sq cm  50  2.5 m / 8' 2"  1.6m /5' 3"  6” , 15.2cm, 181 sq cm  40  3.5 m / 11' 6"  1.95m / 6' 4.8"  8” , 20.3cm, 324 sq cm  50  2.3 m / 7' 7"  1.6m /5' 3"  8” , 20.3cm, 324 sq cm  40  3.1 m / 10' 2"  1.95m / 6' 4.8"  10” , 25.4cm, 507 sq cm  50  1.98 m / 6' 6"  1.6m /5' 3"  10” , 25.4cm, 507 sq cm  40  2.8 m / 9' 2"  1.95m / 6' 4.8"  It would be very nice to have a good compression driver with 4” throat and to load it into 4m /13 foot horn. The biggest problem in here however is not the horn (that is a bitch itself) but the driver. Who the hell has a good driver with 4” throat that will be able to do 40Hz -50Hz and to sound “interesting”. The Japanese manufactures GOTO and ALE reportedly heavy and expensive bass drivers that might do the job but where is the assurance that they have interesting sound or even sound appropriately? I do not trust to those people (in fact I do not trust to anybody), their drivers are not available for experiments and whatever people do build with GOTO/ALE I do not like. What it important in this paragraph to memories that the biggest problem with GOTO/ALE drivers that they are the drivers with “predetermined” sonic quality and the quality of them unknown. So, sanest solution would be to open up throat and look for larges driver. This would make the horn shorter that does not suck too much, but we I not want to go for too large throat as I will loss the horn gain at lower octave. The 6” is looks like fine throat but if I have my driver that I like is 15” then it will do too big front chamber. The 8” probable will do better with 3M 40Hz horn – almost manageable, isn’t it? Well, yes and not. Remember I was bitching about the unknown sonic quality, the unpredictable TTH characteristic of GOTO/ALE bass drivers? I have a very high confidence in the TTH quality of my selected 15” drivers that is used as compression drivers in my hypothetic midbass but there is behind my confidence a very big slippery moment.  Regardless what you heard from anyone and anywhere there are a few absolutely invariable rules on horns. They are not my own rules but they universal are the rules with what you can’t fuck with. I call them “Macondo's Axioms”, not particularly because they are implemented in Macondo bur because I discovered them while I was playing with Macondo (search for Macondo's Axioms if you wish more). So, one of unconditional postulates of the Macondo's Axioms is that it is absolutely impossible to predict how the sound of driver will be changed what the driver will be loaded into a horn.  I know, I know, I know… I see a crowd of Morons armed HornResps, T/S characteristics, Earl Geddes’ assurances and other irrelevant craps scream in response that what I just said is not true. But trust me - they do not know anything about Sound - I do. The truth is that in driver-horn interaction besides the common algorithmable mass-reactance paradigm there are so many other satellites that the final TTH modification of a horn-loaded driver is absolutely non–predicable. Where does it leave me? It leaves me with the fact that my beloved 151-10/40 driver of 15” sounds extraordinary but I know it when the driver is load into 15” throat. I have absolutely not idea how the Sound will change when it will be loaded to 8” or 6” throat.  I might become even better but there is no way to know it, the very same as with GOTO/ALE bass drivers… About my hunch. Generally I feel that the drivers that slightly compress sound at open air sound better in horns. My 15-inchers sound in open air or within a very low compression of 15” throat very nice and very full. This is not a good sign. However, I have no idea how big from the cone mass of the given driver the reactance of the 12” long horn would be and how the driver will be behave sonically when I begin to harden it with the  back chamber. Some drivers bloom in this application and some loose colors, contacts and other “exoteric” characteristics. The point is that it is absolutely imposable to know what driver will do until you build the damn horn, put the driver in use and see what happen. An additional sad thing is that even among those few who have done something near-similar not one passes any constrictive critical feedback about the results. So, in the environment of complete lack of clarity what would happen with the sound of a given loaded driver the decision to do for 4”, 6” or 8” throat become pure arbitrary and at this point I have no slightest idea what I would do it I go there.

http://www.RomyTheCat.com/TreeItem.aspx?PostID=13409

 I put some numbers together to see how a 60Hz horn might look like. I used ½ horn with 324 cm2 throat (8” diameter), Exponential with Hyperbolic curve at .75.  This type of the horn might be 181cm long, a bit under 6 feet and with mouth of 4.3 feet – you know - it not too huge horn. I think I need to learn if the 60Hz source located at the location where my midbass horns are planning to be will be exposed to the same 60Hz room mode. This is the most complex to foresee…

msaudio wrote:

Romy    I see were you are going With this horn worship for midbass. It is the correct thing to do "But you still will not be happy with the outcome because it does no go low enough. You will not be happy with 60hz. Then you will need something that goes down to 30hz. My point is your new house will have all those horns in your audio room, then it will look trashy and it will not look like a living room anymore. I would like to see someone build a horn system fire threw the floor so it don't clutter your room. I donot know what kind of basement you have, but think about every option before you start building the horns. When i built mine i used 8in throats with altec 515B woofers. I like cloth surrounds or paper and stiff cones with 35 hz res or lower and at least 98 db at 1 watt output. About closed rear chamber you will not be able to adjust low res. I built mine like a corner enclosure with a bottom firing port that goes out threw the front with the horn flare, you can adjust low res this way and it sounds much better. Donot build the voice of theater style they are the worst box sounding crap.        Preaching horn religion    MSAUDIO

eduardo wrote:

YL 75000 has heavy phase plug indeed ,  rca style (see sketch) while 1250 ( I never had one) gets a fixed metal dome equivalent  to spherical piece on 75000 and rca  plugs without conical shape pointing the exit of throat. Ironically the 1250 looks like simpler than rca style as cone is the same as every driver we know, but throat on the oposite side like rca . I made graphical work on this as i owned 55000 and 75000 then figured out how it could be designed. ALE P1260 looks like a big 75000 (phase plug included) . May be Ale p160 works like  yl 1250 i suspect. P 1260 (3inch throat) crossed 80 hz while P160 (5inch Throat) goes down to horn low end. On the other hand yl 1250 is 3inch throat(not 4inch as I said the post before)and ¡¡16 hz¡¡that is hard to believe (see the response graph) Note the rear duct open but controlled by the cotton fiber(could be regulated) About voice coil height I would say it gets deeper as driver grows in low end response.increasing from 5/7mm (55000) to 10/12mm (75000) reaching may be 20/25 if you look at previous phographs carefully, for YL1250. It makes a lot of sense. I always thougth that the few big drivers would work fine in midbass horn(say 80 hz). My thoughts about low frequency drivers and how to do with it, is complicated question but i would relate things as the keys in order of influence: 1.-the suspension : diameter and length of it (excursion capability) 2-the cone diameter (response capability , efficiency at low freqs) 3-The throat diameter grows( to very low frecuencies a must be)  4-the phase plug or abscence of it (can be only when very big diameter, but then pressure requires limitation of real throat.....so dome without conical shape is enough like yl1250,ale p160 but air exit must be reduced anyhow) as imposibility of say 15 inch driver with very light cone leads to direct radiator working as a driver(No phase plug or air exit reduction). The driver vs direct radiator dilemma efinetly Is a matter of scale , materials , geometry.manufacturing. Always better a driver unit than direct radiator.......to the point it cant be done by "construction and materials limits" The question is to reach the limit. Seems to me that japanese guys went ahead everybody else on this , so ......let´s see.  I will try soon the 75000 unit on 90 hz horn, but I dont trust much to be succesful.I belive that the bigger drivers (said to be 16/20Hz or whatever) will do fine at upper bass but not  the lowest end(not to mention the big horn "problem".  There is some 1250like driver by Ale manufactured  time ago that could be an option as well.  Eduardo, do you use or do you have listening experiences with YL1250 or with other compression bass divers?  If you can differentiate between bass tone and bass pressure then what is you feeling about the tonal capacity of compression bass divers? As I said i never had one, so about low freq driver tone only can talk about Yl 55000 and 75000 on 200hz horn  and have to say that even that horn alone , 6db say 500-2k, is tonally full, you can nearly forget rest of the channels.it pours low frequencies very very well but it is not bass, its upper bass, at best. what I can feel ,though: this kind of drivers are capable of go down much more than what i have heard myself in 200 hz horn,for sure.That´s why i dont quit and will try on 90 hz horn.I think it will work even lower than that and would be fine..... then how much lower? my thougts are that if it works to 90 80 60 hz it would be fantastic. Regards Eduardo