I do not know what the Fs of the drivers that will be using. I did not measure them yet.  I have one of them in ¼ cub feet box with a port making 65Hz and two of them in 1/2 cub feet box making 38Hz. If I found more of the them then will be unit 4 of them per box, so I presume that I will be able to go quite low in 2-3 cub feet box. If I do have a notion in my head that the ported bass will suck anyhow then why do not get a full bass?

Well, here where I hit a problem. The “suck ported bass” is not a Boolean but it has moderation and it might be “the better crappy ported bass” and “worse crappy ported bass”. The keys in it are some kind of agreeable with subjective results moderation that would greatly depends of the specific implementation.   If you look at the LBJ, Petar and few others who try to help me in the MiniMe thinking then it is obverses that there are some “kinks” that would move the posted bass from “bad” to “horrible” but I am affair that without the trials and actual evaluation of the results it is very difficult to say how it will works, particularly if I am willing to get MORE bass and to drive the port resonance all the way down as far as the array of the 4 driver permits me.

So, at think moment I think where the get those drivers of mine and when I get them then I will come up with some kind of steel enclose the THEN will be bitching to anyone that it sounds very “porty”. However, the single 4” woofer that I found in ¼ cub feet with port (with temp tweeter), even those it has all characteristic of the “bad port sound”,  still does excellent in context of the requirement and defends I impose to the  MiniMe acoustic system. If I have in my final MiniMe version the same LF Sound that I am getting now from ¼ cub feet box (I hope to get less port noise due to 4 drivers and much larger enclosure) then supplementing with much-much better tweeter and spiced some interesting techniques the those woofer allow to employ (Some form of the “Resonant Oops”) I feel it will be happy like clam.

For the sake of helpfullness, I think that we may separate the differences of the ported speaker designs of myself and Petar.  What I have described is the standard, pedistrian model of a vented speaker.  Petar's is a hybrid aperiodic-ported design.  It is a less-than-vented design tuned to a particular frequency.  It's nice and can probably produce a nicer sound than a purely vented design, but in Romy's application (getting somewhat acceptable bass from 4 inch drivers) it may cut the effect of the port to severely.

Let me tell you about the small speakers that I built and had mentioned earlier.  They used the Peerless 830854 poly midwoofer with an Fs of about 75 Hz.  The goal of the speaker was essentially the same as Romy's...Small with relatively okay bass.  After a lot of modifications (including an Oops resonating soundboard back) to the origional design, it was successful.  I could play Bach's 2nd Cello Suite on them and enjoy it without the port farting out an indistinct noise.  They were very pleasant in the context of non-serious listening.  They measure just about 5.5 inches deep, 11 inches high, 7.5 inches wide (roughly) and I powered their 87 dB sensitivity with a barbarian Crown amplifier.  Once I have a place at home to set up, I'll be using them again, exactly as I did before...As my "its not a musical instrument but it won't piss me off" speaker.

I am very familiar with the ported M-Audio BX-5a "studio monitor."  Perhaps I am dimwitted, but I have no idea how these commercial companies can be so talented at making a port sound like a port!!!  Not only does the carbon fiber cone impart such a revolting, idiotic, tone, but the wildly flaired port blows and humms until my ears run with blood!  Not even in my days of dumpster diving for free drivers have I gotten such bad port sound as I have heard from nearly all commercial speakers.  It may relate to the thin walled plastic or cardboard ports they use.  My newer ports are made exactly like your horns, just with a straight profile...Stacked and glued MDF.  One difference of the port in my MiniMe speakers is that they are ABS pipe that have been damped and lined with an idea that I ripped off from B&W.  Their big thing is dimpling their flaires like the surface of a golf ball.  Not to be outdone (I was like that in those days), I spread on epoxy and lined the inside of the port with silica gel balls!  The damping effect of this treatment was probably much more beneficial that the aerodymic aspects, however.

Anyway, the best advice I can give is to make your enclosure very versitile.  With your drivers, with your amps, with your sources, with your goals, and your music, they are going to need to be very much your speakers...not mine or anyone else's.  Building a purely ported design could bring the results I think you are looking for. 

As for tuning the ports below the drivers Fs; give it a try... I've heard the "flapping cone" sound, I did some hands-on research.  I recently repaired the amplifier of a pair of self-amplified Bose speakers.  I pluged the passive speaker into my system and listened to it produce some really screechy, shouting, terrible sound.  Once I had the amp fixed, I fired them up to hear the really bad cone flapping drone without the shout or the peaky mid frequencies.  Obviously, Better Sound Through Research means using an equilizer to "fix" a fundamentally flawed speaker.  So, with the recent findings, I am reconcidering my "impossible to use port's below Fs" attitude.

Kindest Regards,
LBJ

Thanks, LBJ, I ma slowly getting into where I would to be in term of understanding, at least it is what I think I do. You are perfectly identified what I am shooting for: "its not a musical instrument but it won't piss me off", it is exactly what I would like it to be.

I few more questions. Take a look at the image below:

The difference would be juts the volume of the boxes and the consequentially the lower loading of the drivers in infinite baffle state, theoretically in larger box I might drive the driver have in “sealed state” but would be port acting in oversized box differently? I can make the box at tall as 72” but I do not think that my driver will be able to pressurize this volume. As I understand the port shell kick-in at the bottom of the acoustic suspension (hypothetically spanking). So, if I get 8 of those drivers then I can pressure-load a larger box and let the port to do less. Correct me if my assumptions are wrong.

 And one more question. What you feel would be a difference between those 3 cases?

Very good.  Raal 70-20XR...interesting.  Where are you planning to cross these over?

I remember the discussion about the internal balloon.  That is a very good idea and this may be the perfect opportunity to try it.  It will also be interesting opportunity to work on enclosure damping methods.  Being made of steel, they will probably make all kinds of noise without some help.  I have used frequency sweeps and a stethoscope to find the resonant modes in enclosures and strategically damped them out.  It worked out very well.  Today, I thought of something that may be worth trying.  With a steel enclosure, you might try glueing (silicone glue would be perfect) some hockey pucks over the most resonant areas.  It should work, they are easily removed if it doesn't, and best of all, hockey pucks cost 99¢ each.

LBJ

Lbjefferies7 wrote:

Very good.  Raal 70-20XR...interesting.

Oh, yes, the 70-20XR is very interesting. I did not have this driver but Alex allowed me to experimented with some elements of it’s design in context on my “Water Drop” tweeter and it was quite remarkable. I end up do not use those “elements of it’s design” with “Water Drop” as my tweeter has different objectives but in context of the 2-way MiniMe the 70-20XR’s “elements of it’s design” shell show themselves vey very positively.

Lbjefferies7 wrote:

Where are you planning to cross these over?

You have no idea how loaded this question. The crossover point with the MiniMe is not a tactical question but actually the very strategic question of the entire speaker, let me to explain why. The woofers that I use are fairly bizarre – they are what made me to think about the MiniMe. They have diaphragms made with reinforced fabric, the outer suspension is rubber. However, the reinforced fabric is semi-soft in the similar elasticity as the outer suspension. So, it is not a piston motion (like in foolish ceramic drivers) but rather motions with a lot of break ups – the right motion in my books. But then is the kink of the driver- the dust cap. The dust cap is inverted dome of aluminum and it the way how it placed makes the dust cap as the literally keystone of the diaphragm resonance. It is sort of the resonance’s lighting rod – if you see the driver then you understand why I got enthusiastic about it. Now, the woofer goes up, let say to 4K-5K and the dust cap begin to ring. The similar effect to JBL LE8 that also has metal dust cap. Here is where I will be playing with my woofer – to tune by ears the dust cap’s resonances. You see, that dust cap ring in a very measured dosage is in fact very good (in context of these speakers) as it works like the “Oops-resonator”. I will damp the dust cap by painting the driver with volcanic ash (no speaker white cones in my home!!!). That will extend the safe operation of the driver for 500-1000Hz up but the primary tuning tool for me will be the crossover point. So, I will be searching for crossover point by just listening the Oopses with witch the woofer’s dust cap will resonate – where it will become too much Oops then I will cross right there… Well, here is the question: how the woofer’s dust cap will behave if I have 6-8 woofers per channel and the excursion of each woofer is substantially minimized? I have no answer now but I think I will found another 2K of response. Then we have the HF’s cancelation coming from the line-array configuration… It will eat the HF but will it each the dust cap Oops-resonances with the same appetite? I have no answer now… How the “not eaten” residues of the HF woofer resonances will be “subjectively friendly” to the distortions of the 70-20XR tweeter’s lower knee? I have no answer at this point. I need to found the woofers, to build the box to screw the array of the woofers and the tweeter in and start to run the crossover point up and down, to hear how it will work all together. I have no planning to cross at a specific point I will cross it wherever it will be, I anticipate that it will be somewhere between 2K and 6K, most likely a second order.

Lbjefferies7 wrote:

I remember the discussion about the internal balloon.  That is a very good idea and this may be the perfect opportunity to try it.  It will also be interesting opportunity to work on enclosure damping methods.  Being made of steel, they will probably make all kinds of noise without some help.  I have used frequency sweeps and a stethoscope to find the resonant modes in enclosures and strategically damped them out.  It worked out very well.  Today, I thought of something that may be worth trying.  With a steel enclosure, you might try glueing (silicone glue would be perfect) some hockey pucks over the most resonant areas.  It should work, they are easily removed if it doesn't, and best of all, hockey pucks cost 99¢ each.

Hm, in interesting idea – to offset the box resonances by targeted mass-damping – sort of rotationally balance a car’s wheel by adding mass on one side. I think it might work with light enclosures. I do not think it will work with heavy and stiff enclosure as I am planning to do. As you understand from my previous paragraph it will be a lot of active resonances radiated out of this speaker, so I presume that the enclosure resonances will be a least of my problem. I do not decided with steel finally. I know that I am not willing to do anything myself with enclosure. I will design it (after I know how many woofer I will be able to fish out), get a quote for my machinist and then see what other material are available. It will not be 1” of wood but a few mm of something very strong- steel, aluminum or architecture plastic (Perhaps the material-savvy Jessie could advise something). Anyhow I will try to keep the dimension of the baffle as little as possible….

Romy the Cat wrote:

It will not be 1” of wood but a few mm of something very strong- steel, aluminum or architecture plastic

Romy the Cat wrote:

You have no idea how loaded this question. The crossover point with the MiniMe is not a tactical question but actually the very strategic question of the entire speaker, let me to explain why. The woofers that I use are fairly bizarre – they are what made me to think about the MiniMe. They have diaphragms made with reinforced fabric, the outer suspension is rubber. However, the reinforced fabric is semi-soft in the similar elasticity as the outer suspension. So, it is not a piston motion (like in foolish ceramic drivers) but rather motions with a lot of break ups – the right motion in my books. But then is the kink of the driver- the dust cap. The dust cap is inverted dome of aluminum and it the way how it placed makes the dust cap as the literally keystone of the diaphragm resonance. It is sort of the resonance’s lighting rod – if you see the driver then you understand why I got enthusiastic about it. Now, the woofer goes up, let say to 4K-5K and the dust cap begin to ring. The similar effect to JBL LE8 that also has metal dust cap. Here is where I will be playing with my woofer – to tune by ears the dust cap’s resonances. You see, that dust cap ring in a very measured dosage is in fact very good (in context of these speakers) as it works like the “Oops-resonator”. I will damp the dust cap by painting the driver with volcanic ash (no speaker white cones in my home!!!). That will extend the safe operation of the driver for 500-1000Hz up but the primary tuning tool for me will be the crossover point. So, I will be searching for crossover point by just listening the Oopses with witch the woofer’s dust cap will resonate – where it will become too much Oops then I will cross right there… Well, here is the question: how the woofer’s dust cap will behave if I have 6-8 woofers per channel and the excursion of each woofer is substantially minimized? I have no answer now but I think I will found another 2K of response. Then we have the HF’s cancelation coming from the line-array configuration… It will eat the HF but will it each the dust cap Oops-resonances with the same appetite? I have no answer now… How the “not eaten” residues of the HF woofer resonances will be “subjectively friendly” to the distortions of the 70-20XR tweeter’s lower knee? I have no answer at this point. I need to found the woofers, to build the box to screw the array of the woofers and the tweeter in and start to run the crossover point up and down, to hear how it will work all together. I have no planning to cross at a specific point I will cross it wherever it will be, I anticipate that it will be somewhere between 2K and 6K, most likely a second order.

So, it is no luck for me and I need to hunt in used market the speakers and get my woofers from them (that why I do not divulge the brand and model under which Mission sold my woofers).  Well, those guys who do mass production of speakers – they are in so cool state – the can make any specification for any diver then want…

Wojtek wrote:

Funny , I visited a guy who  ususally picks up audio stuff from the curb (garbage picking) and noticed some 4 small Mission midbass woofers with crossovers. He said cab wasn't worth to save . What are the serial/ type numbers on yours, maybe they are what you're looking for ?. REgards, W

The 6moons’ Srajan Ebaen published a writing about Austisn David Haigner’s loudspeaker where David goes into some extend taking about his implementation of the bass reflex idea. The article made as Srajan’s narrative but in fact it is obvious that the “review” is juts David’s dictations. With the same success Srajan might juts record the Haigner’s comments and to attach to the review as mp3 file (you will see this practice coming very soon). The Srajan’s review has no comments about the sound of the Haigner’s loudspeaker. Sure why to make any comments! If to say that it sound not good then David would pull out the advertising from 6moons site. If to say that the speaker sounds very good then somebody not-deaf might buy the loudspeaker and to witness that Ebaen is a full of blabbering shit. Probably it is better to make sexy still-life pictures and publish the transcripts of the word of other, presenting it as own “wisdom”. Here is the way to go Mr. Reviewer!

Anyhow, if somebody is interested in the David Haigner’s thinking then here it comes:

http://www.6moons.com/audioreviews/haigner/rho.html

http://www.6moons.com/audioreviews/haigner/sidebar.html

I find it interesting but not too useful for myself as I do not fell that David connect subjective character of Sound with technical-measurable data. I presume that Mr. Haigner has some methodologies how to deal with it but it did not make in his commentaries to the 6moons’ guy.

Looking for off the shelf solutions of the adjustable port idea I came across to an Illinois company Precision Sound that looks like specializes on ports themselves.

http://www.psp-inc.com/

They have some papers that I am looking through

http://www.patentstorm.us/patents/5623132/claims.html

I wish I had more experience with port design to be able evaluate the validity of claims.

I have some strange feeling about this MiniMe idea and I really hate those feelings. The entire concept of MiniMe was to have painlessly integrated with large-speakers mini-monitor with somehow “not to revolting sound”. However, as I go slowly along with this idea I more getting interests in what the sound of this ported speaker might lead into, particularly the  selection of the relatively interesting drivers. Lately I made a number of experiments with location this one of my prototypes (it uses the same bass drivers) and I concluded that if let the mini-monitor to stand-alone on the side of the upper-bass bay then I have WAY more interning results (imaging etc). Interesting the in this location it practically not intrusive in the room decor and take no space (it will be 5” wide). However, then the Pandora Box for many other bad thoughts got opened...

OK, if the MiniMe will be a stand-alone, floor-standing 43’ thin mini-monitor then the MMTTMM configuration will not work and I must to go for TMMMM configuration. The top-bottom ports will not work and I need to go for back ports. I will have no depth of the box limitation and I can go as deep as 12”, if so then the box might have a room on the side for larger LF transducer… The and-alone box might have different, more suitable for it’s location enclosure shape. The integrated box shall have Macondo Frame mounting brackets and HF deflectors. If I go do G10 then it is impossible to weld the brackets…

I can go on with many new opportunities that opened if I do not mount the MiniMe inot the Macondo frame but the the biggest question strikes me: why do I need a second good sounding speaker? Here is my interest between leaning how the speaker might sound if everything is done objectionably and how it will sound if it den with “little blood” conflicts. The two different directions requires deferent design decisions and they are not real dual useable. I have no decision at this point…

drdna wrote:

I would not restrict myself to the idea that things need to be a certain way or a certain configuration of the drivers or ports based on theory alone. I think it is important to ask what is interesting about the sound that the new speaker introduces into the system and how it accomplishes this, then focus on refining this in the approach to the new mini monitors. Adrian

Well, it is not about the “ideas that things need to be a certain way but or a certain configuration of the drivers”. The Macondo frame mounted version and free-standing version would be different as the height of the tweeter much be different. If it mounted in frame then the tweeter shell be at the height of the Macondo’s tweeter and the dimensions are very firm and very strict. I would have much more liberty if it would be a free-stating version. Another problem that is in free-stating version some postulates that I accepted for MiniMe’s idea (like use 4” drivers) shell not be necessary rule.

From a different perspective you are right and if I am interested in the Sound of the speakers then why should I have those artificial boundaries. Well, here is where I thing the problem lies: I am interested about the sound of this thing but I am not sure if I go for “refining” and I do not really need a refine monitor. I mean I would like it to be better but I do not want to spend efforts, time and acquire knowledge to make it better.  I am OK to conceptualize the things, found the interesting drivers, outsource the building and then just to listen the results, perhaps playing a bit with posts and crossovers. I really do not want to do anything else and if I need better sound then from the MiniMe monitor then I just turn the Big Macondo on.

CO wrote:

I agree with Adrian. Dont think too much and set the speakers up and start changing from there, you know its going to change again anyway.. In that light it might be even better to start with a standard mdf cabinet to experiment with port configurations...

Yes, Collin, you are right and this is right way to do the things but I am, not going there- I will have just one shot and it will be it. I am not in the business of DIY speakers self-amusement and I do not see myself making a second MiniMe run. If the adjustable port idea will not work then I juts rise the port’s resonance frequency until it will be good and it will be it.

CO wrote:

You dont need these but you know its fun to do and a new possibility to learn from it. Its an sonic itch.

Yes, I agree there is some fun in it and I am very much would like to hear how those unique 4” woofers of mine would sound in an array of 4 drivers.

CO wrote:

What is the reason for placing them so close to the main system, also for injection ? Otherwise a completely different location could be more beneficial / educating since were not playing with horns here.

There are few reasons. If it will be a standalone version then it will be most likely 5X9X42. As you can see the 5” is very small frontal footprint and it is how I would like to have it. The Macondo’s upper bass channels are macro-imbedded into the hot spots of the room:

http://www.romythecat.com/LatestPosts.aspx?ThreadID=4421

...and it is the same location what I would like to put my MiniMe if they are standalone monitors. I run currently a single left-channel monitor from the hot spot and it files the whole room very beautifully. However, staging there the monitor need to be very small, thin and not obtrusive for Macondo own sound.

The idea that I have at the top of my head are like this: it is 5X9X42-43 in TMMMM configuration with one port at the bottom. It will be adjustable legs at the bottom to lift the port from the floor and to moderate the port “external loading” (I have no idea if it “works” I think it shell). So, I see nothing overly exiting about this idea, there are zillion speakers like this out there. Might will have “interesting drivers” and 5X9 (9 being a dept) footprint. Will the speaker “collapse” then it plays serious music (like all other small speakers do), will it compress, will it have any tone, will it distort at high volume and many other “ifs” – I have no idea. Generally, if it were a freestanding (and I slowly move toward this notion) then I would like to have a third channel- right under the RAAL 70-20RX tweeter I would like to have 4” MF driver. I would like to have something of tonal quality of JBL LE8 only 4” diameter and with sensitively of 95-98dB. I do not mind if it was an expensive driver. I presume that I might use this driver from 300-800Hz to 3000-5000K – a very good range for a good MF. Oliver, if you read it, did Görlich make 4-inchers? Does Scanspek has MF 4-inchers drivers with SD-1 motors that more then 89dB sensitively? I have no knowledge about MF 4-inchers if somebody have an idea feel free to share some leads…

ScanSpeak's 4.5" mid looks nice, but it's still 89dB
http://www.madisound.com/catalog/product_info.php?manufacturers_id=148&products_id=917 
Eton's 4" Symphony looks real nice, but it's only 88dB
http://www.madisound.com/catalog/product_info.php?manufacturers_id=128&products_id=8481 

How about Fostex? 
Don't know if you could find any FE108ES IIs, but I really like them in a second system, in that range (not trying to use them "full range"). 
Really nice tone, good detail, doesn't compress louder than I want to listen to them, even when listening to large symphonic works, or as my wife does, to pick out her part in massed chorale works, e.g. Durufle Requiem Op 9, which has a pretty large dynamic contrast. 

A few pair of FE138 ES-Rs are left if you're interested in going to 5", down to 91.5 dB
http://www.madisound.com/catalog/product_info.php?products_id=8480 ($459 ea there, but information is on that link)
http://www.eifl.co.jp/index/export/export2.htm (one pair left @ $800 / pair)
Or 3.46" FE88ES-Rs.  

And what's with the G10? 
Does it have some special damping properties or something? 
As a machinist I really hate the nasty stuff... 
I don't see why anyone would build anything out of it if you could use anything else if you've ever used it before. 
Wood's a lot easier and less expensive. 
As are various metals. 
Robert

Robert, G10 has no special damping properties that I detected. In fact it is some kind of plastic feeling material. It is “filament glass cloth material with an epoxy resin binder”.

http://www.polymerplastics.com/composite_g10.shtml

I do not fine it as “intellectually pleasant” as LBJ find it. I think gold is rather intellectually pleasant. However, I do find that the G10 is very pleasant to tough. It has that wet and leaky feeling that Teflon has but G10 is harder. It also appears that it has no epoxy-like hardness but “softer”. I do not know about self-damping but I do not think so. The G10  box I presume will sound like plastic box – I see no reason why it shell not. However, my bass drivers are in the very same page: the harden cloth. It all might just work all together… The only problem that I see with G10 is that I shall have more thinness and more bracing than it would need with still of aluminum… anyhow I have no judgment at this point what materiel I would use… I have no way to predict result until the box is made anyhow…

Regarding the 4’ MF driver. I do not know if I need it, I do not know how I might be using it and I do not have a lead idea what driver it might be. Some drivers were proposed. I would like do not have a rubber suspension I would like the mounting size of the driver be no more then 5” (the max width of the front baffle). For instance the AudioTechnology 4H521306, Foxtex 120A might be near OK if I use 2 of them but they are too wide.  I would like very much the monitor to be able to play loud, none of them do and I hate it. Therefore I need 2-3 octave in MF driver before the driver roll off kick in and thus something like ATC SM75-150S might be out of picture. So, the 4” drivers with primary resonance of 200-300Hz are out of picture and I need 70-90Hz of Fs if I cross at 700Hz.  Anyhow at this moment at the lead position is JBL LE5-2 or JBL 2105, side-wide they might barely fit. I never heard them but I have intimate knowledge about LE-8 and I like them a lot. I migh hope that the 5-incher would be in the same family of sound…