Doc modding Marantz imperial 7

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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

royj's avatar
royj151 posts
03-21-2018 11:02pm
Dave and Troy, I do understand your points above, which were:

In our view a system which is tuned so that everything sounds good including bad recordings, you know you are going to have a system which has rolled off top end and perhaps a slightly fat midrange.
VS.
A system which makes things sound real and life like, if the recording is not good so will be the sound, but of course a good recording will be glorious.

So of course each person's system is going to mirror their tastes.

If you understand the context of the original question, it will help you understand our point.

Yes we tune our systems to sound natural and we feel that natural is musical, but in this context it means accurate without being unrealistically bright vs a system which is deliberatly tuned as mentioned above.

Dave and Troy
Audio Doctor NJ
What you propose is a sensible and logical goal. But a system being musical is not about a system tuned so even bad recordings sound great. But the converse will be true.
It is not about a system which makes things sound real and lifelike. But the converse can be true.
It is not about a system being accurate without being unrealistically bright.

seanheiss1 above has it right:
Defining musical is like defining how to dance. We know when someone can dance just like we should know when something is musical. PRaT?
prof, you wrote above:
If instead you give more detail about what specifically you mean by “musical” - actual sonic characteristics - then who knows we may agree. But if it reduces to various forms of “does it move you” then that, as I say is subjective, differs between listeners and therefore not a useful heuristic for identifying anyone being wrong or right about the musical capabilities of a system.
Thanks for pointing this out, prof. What I have found over the years, quite by surprise, is how most right-brained listeners appreciate most music when played on a musical system. The music may not be their cup of tea, but they, far more often than not, smile and listen and come away feeling like they understand why others could really get into that. This never happens on an amusical system.

When I am describing musicality, I can use only words that convey feelings, emotions, and physical motions like toe-tapping (thanks, ctsooner!). If, like jon_5912, you do not agree, please consider you have received my best advice on what to listen for and what to read into reviews.

Most reviewers have not heard musical systems, or cannot hear when a system is musical, cannot feel when a system is musical. If they did, they would write about that before ever writing about soundstaging, details, dynamics. This is because to anyone able to experience musicality finds that something far more important to report about a product. This is a part of Joe Walsh's message that nitrobob related. Is the music fun even on a car stereo? Again, read magazines like Tape Op to learn the magic that studio pros try to capture, want to reproduce, because they can surely never, ever capture 'reality'.

I would add that we audiophiles could ask women and artistic people's to hear our systems. If their attention is not instantly grabbed and then held by almost any great artist, at a soft volume, that system needs work.

An important aspect of a musical system is finding out, unexpectedly, that we have no motivation to play a different selection right away- drawn in automatically to hearing the entire record or CD. We are lost in the performance, never thinking of its details, image, 'bass' or 'highs', impact, dynamic contrasts... unless one has sat down to listen precisely for those things. this takes ears educated, trained, in ways right-brained people do not get and can seldom be trained. The same goes for power tools, right?

On a truly musical system, those wired emotionally experience feelings best described with words like power and floating and singing and dancing and crying, yelling ,drifting, plunging, spinning, surprising, lilting, laughing, shredding, burning, ... Spontaneous new associations made from associations hidden in the music- concepts only music can communicate.

Words are insufficient to communicate what music does. This is not elitism, but acknowledging those listeners are limited in vocabulary to describe experiences. Ask them!

If you don't get that from your stereo, it is that system's fault IF you initially loved music as a teenager, no matter what the system. On the other hand, if you got into advanced audio because of the tech, then you have to work harder to connect with the music emotionally, hence my earlier advice.

And you are both right, prof and d2girls, about the sound of real horns not being aggressive or bright. Same goes for cymbals. I find these are problems caused mostly by non-time-coherent speakers which literally shred HF transients. This leads to seans' comment of
Basically, as sounds get louder, they abruptly go from being inaudible to painfully loud.
Not true from any real instruments nor from time-coherent speakers. Go to a music store for goodness' sake and ask someone to play something!!

prof, your son who loves his music on his laptop and iPhone is still highly right-brained would be my answer, since teenagers are not rational beings. I think it worth noting that since good musicians are very right-brained, how many of those need or want a fancy hi-fi? It is not a high percentage.

This is what I would ask to try all of us to remember-- the experiences we first had back when we fell in love with music, a place in our lives that experiencing the music came first.

I hope my advice can be a guide out of the tremendous amount of non-musical gear out there. What do I do for our clients? Recommend certain brands and let them see the customer feedback to be, wait for it, always about musicality.

Sorry for the long post, but the variety of musings were nice to see and worth addressing. Thanks!

Best,
Roy
DIY inspired by Richard "The Doc" Dunn RIP

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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Haven't i got anything better to do at 9.30 on a saturday night ? Well no. I'm listening to music via Amazon music and enjoying it immensely. Skipped a few tracks but hey you can't like everything. Wife out, kids in bed. San miguel is flowing :guiness;

This is a corker :dance:

Oh, I left a dissenters reply between these two posts of Roy's for a bit of perspective. Ring any bells ?

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royj151 posts
03-21-2018 2:37am
I appreciate the discussion.

Some observations to share:
After a few decades of demonstration, I have no doubt there can be a strong left-brain/right-brain difference among listeners, and some listeners are in the middle, who eventually make emotional and physical connections to their music- their wives certainly did, right away! All this does assume the system is musical in the first place.

When I was in high school, the left-brained ran the A/V dept, getting out the film projectors, running them for class. A few years later, that became TVs and VCRs. I observed that none could or would dance. None played instruments, sang, nor was interested in any of the arts. No one can deny that many of these technical fellows became audio designers (and reviewers, and magazine editors).

I have watched countless individuals, including reviewers, clearly not hear when one system at a show was exceedingly musical compared to many other systems nearby.

Most reviews start off with observations on 'detail', 'imaging', 'impact', and so on. Few begin with 'musicality' and 'engagement' or 'involvement'. Perhaps this is reflective of those reviewers and even of how poorly their room is setup, more so than the gear. But if some piece of kit was truly musical by a large margin, you'd think an experienced reviewer would hear this right away and report on it. So, I take this to mean that most gear is not musical. Which has been my experience.

Regular CDs can be extraordinarily musical yet lacking no details, even on solid-state systems. The trouble seems to be with playback, not with their recording, and I have the recording background to back up this observation. But I have only ever heard this four times since the advent of the CD, and neither system complexity nor price were necessarily why.

How do we know what to hear from a recording when we were not in the studio? We know it when we hear it, again, assuming we are wired to respond to musicality. As those are who also sing, play instruments, dance, and appreciate the arts.

I have heard several times some gear combinations come together in their flaws to become truly musical, while still lacking many details of the recordings. Best to leave this as fortuitous luck!

Roy Johnson
Green Mountain Audio
prof2,524 posts
03-21-2018 3:14am
Roy,

The problem I have with your use of the term "musical," and the use of that term in general, is that it is so subjective as to be essentially uninformative.

One person's sterile/analytical is another person's "musical." One person's rich and rolled off system is "musical"and to another "boring and un-engaging."

We've all gone through plenty of systems/speakers that at first were "musical" to us, but which we later abandoned.

There have been many polls along the lines of "what speaker got you off the merry-go-round/which speaker is your life-time speaker?" and the answers for the speaker that finally gave musical satisfaction are all over the map, representing every design approach. Some people find Wilson the bees-knees, others have thought them the antithesis of what they are looking for in music reproduction.

So when you tell me you find something "musical" all I can gather is that you like it. The fact some other people didn't "recognize" something as musical like yourself isn't an objective failing on their part, anymore as your failure to find their choice to be musical.
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royj151 posts
03-21-2018 3:45am
Thank you for your thoughts.

When you write "One person’s sterile/analytical is another person’s "musical." One person’s rich and rolled off system is "musical"and to another "boring and un-engaging.", those are exactly my points, about how the non-musical listeners just do not get ’it’, over and over. It is indeed as you write, prof!

It is important to always examine what is engaging you, what is attracting YOUR attention. Is it detail, image, tone balance, richness and rolloff? Or is it the band having one hell of a joyous time?

When one cannot hear the latter, for whatever reason, this leaves of course only the former as the experience to be taken away.

Again, no criticism is intended. This is just my experience and of very many others with professional (also meaning ’daily’ across many years), high-end experience. The point from this discussion I think is not to make labels or set up challenges, but simply to work harder at finding the truly musical gear. I have found it is always best to do so by reliance upon recordings of world-class, one-in-a-billion artists, not the second-tier ones signed to audiophile labels. The musicality, the beauty of the top artists will come through regardless of the recording quality, if the system allows it AND the listener is wired to appreciate that. Those who are not wired in this manner do not understand my point and can seldom be ’trained’.

Also, experienced (and famous) recording engineers always say, "It is never the quality of the gear, but the band being on fire that makes the difference."

I recommend Tape Op Magazine -- a studio magazine not beholding to advertisers, with all articles by working pros. It is free and at least one article in each issue seems useful to us audiophiles, about what these men and women hear! By the way, when you write,
"The fact some other people didn’t "recognize" something as musical like yourself isn’t an objective failing on their part, anymore as your failure to find their choice to be musical."
this is wrong. It is indeed an objective failing on their part because I and many others can easily point out the many non-musical differences. Granted, this can take a very long time to do for someone not used to listening for musicality, which is why the world-class artists represent one’s best chance at learning about musicality. Also, read the CD reviews on Amazon, about which performances of an artist to purchase, which ones captured best their special magic.

Best,
Roy
DIY inspired by Richard "The Doc" Dunn RIP

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Re: Doc modding Marantz imperial 7

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"Also, experienced (and famous) recording engineers always say, "It is never the quality of the gear, but the band being on fire that makes the difference"

This little snippet says it all for me. In the 90's I went to record a live demo album at a recording studio opposite Yorkshire TV on Vicar Lane Leeds. They did loads of work for YTV and some of the Smurf's albums were recorded there - I saw the discs on the wall :lol: Anyway we went there ( can't remember why there) to record all of our songs live just to have something professionally recorded, no over dubs or any other devilry.

We played our socks off, everyone was playing their best despite the amount of dope we had smoked but most of all we were all getting along like a house on fire and playing together not for ourselves. This led to the people who owned the studio offering us a recording contract with a healthy up front payment. I built the sound proof rehearsal room at the family farm with some of that money. That demo was a blinder, we were on fire and it all felt good.

Then we went in to the recording studio to record a "proper" album for free as it were. This is where it all turned to shite. Everybody playing their parts seperately to a backing track. I was the first to record my parts. Essentially it was the whole band playing but all in different rooms with headphones. I played to a click track and that is a real emotion killer. At that point I was the only one actually being recorded.

The months that followed involved the other band members putting their parts over the top of mine. It was on the whole a music killing exercise. Apart from the bass player the rest of the band got so far up their own arse it was unbelievable. They re did parts so many times I think they forgot the original part they came up with that worked so well. The musical feeling had long since left the building much like Elvis.

I can't listen to that recording but I sometimes listen to the original live demo. We broke up about three years later mostly coz I wanted to punch the singer. But we did get to go to Yorkshire tv Christmas doo. That was quite an event. Got to meet Richard Whitely who was a right grumpy old git and Whispering Bob who loved our music cos it was ever so slightly country. Couldn't help staring at his awful teeth though which I think he has had so e work done on since. And the studio producer's wife wanted to shag me. She was a real stunner but I was too pissed to do anything about it.

Anyway, Roy's ramblings certainly strike a chord with me. If you can't feelit, if it doesn't move you emotionally then give up.
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Speaker experiment of the day = different ways of wiring up multiple drivers of the same type :grin:

Drivers - two 12" bass in isobaric loading, two 5.25" mid bass in push push configuration (one inverted ), four tweeters all wired in series with 1uf series cap high pass filter.

When I had all my amps wired up to these speakers I had one for the 12 inchers with the two drivers in parallel. The two 5 inchers had there own amp and were wired in parallel. The four tweeters had their own amp and were wired in series. Well I tried wiring the 12" in series and I think I preferred it (can't quite remember - should take notes) and the same happened with the 5".

We can play all sorts of wiring scheme games with these doped drivers that don't have any electrical crossover :dance: that you couldn't do easily with crossovers as you would have to redesign the crossover every time you changed it.

For quite a while I have been running my speakers from just one dual mono amplifier with no front end's split off. Back to basics as it were. It has been very enjoyable and not really missed the six pack with twelve psu's. I am not saying it is not better with the six pack , just this simple set up is highly enjoyable in it's own right.

So I came up with a way of wiring all those drivers up and still having an amp friendly load. The two 12" (wired in series) were wired in parallel to the two 5" (wired in series) and in parallel also to the four tweeters (wired in series). That worked very nicely but as I am also wondering what if, I decided to try something different.

Newest wiring scheme is a parallel series affair for the bass and mid bass drivers. The two 12" are wired in parallel but then in series with the two parallel wired mid bass. Took a while to wire it all up with wires and choc blocks everywhere :lol:

Been listening to this arrangement for a quite a while now and what can I say? I really like it, in fact I seem to have found a balance that suits me better than anything I have tried to date in the three years I have been dicking about with speakers. The speakers have a subjective heightened sense of composure all across the frequency range. A few things were continuing to bug about these speakers which I had plans to work on. This new wiring scheme has made me have to think again about what remains to be tweaked.

Odd little irregularities about the bass and mid range have suddenly disappeared in a wisp of smoke. So what is going on here electrically ? I now have different sized speakers in series with each other that have different resonant frequencies, impedance behaviour and TS parameters. There are countless threads littering diyaudio.com saying series wiring is not a good idea. Well so far in my case I have to disagree with all those views. The Doc and DQ like(d) series wiring for bass and mid bass drivers and so do I. What magic is going on or am I just fooling myself and giving subjectivists a bad name ? :lol:
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Going back to the notch I noticed at 120Hz to 150Hz when playing a test tone CD. Here is a quote from Wayne Parham who is the head of Pi speakers in the U.S. They make constant directivity corner horns.
Wayne Parham;2531792 wrote:Absolutely. In-room, all the boundaries come into play. I've often times thrown the phrase "floor bounce" around but in reality what it was is a combination of path length deltas and the vertical modes, probably mostly the second one. I've just noticed that in practically every room, there's a notch around 100-150Hz. And like you, I've noticed the notches above a few hundred Hertz become very small

So Wayne says in almost every room there is a notch at around the same frequency as mine. Now I don't feel so bad :grin:
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Having your bass driver (or one of them :grin: ) at floor level is said to lower the severity of a notch in the bass (<200 Hz). Can't do that with a semi omni unless you have a second bass driver at the floor firing forwards. I did that with mine at one point but never tested for any notches. With a semi omi the bass driver is at roughly 1/3 of the floor to ceiling distance. Who knows what effect that has. Maybe I should just stop worrying about it.
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Re: Doc modding Marantz imperial 7

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My current thinking about rooms and acoustics has led to a bit of a change of plan :roll: . My room at home is only 3.8 x 4.2 M which is much smaller than the one I currently have my diy speakers in at the family farm. Even in that larger room the size of cabinet needed for the 12 inchers is rather imposing. I can't see these monsters working in that small room, aesthetically or sonically :cry:

When you look at the TS parameters for these drivers (found some measurements on a Romanian forum) they have a VAS of 160 litres and qts of 0.45. Now doping a 12 incher is going to add a fair amount of mass which will increase both qts and vas. Not sure how much but potentially enough to push vas up to 200 litres and qts over 0.5. I like a qtc of less than 0.7 and probably closer to 0.5 for some real tight bass.

This is going to be impossible with anything but a cabinet the size of a fridge freezer even with two drivers in clamshell isobaric, the cabinet stuffed and an aperiodic vent. Ideally I reckon these drivers will work best in open baffle or true infinite baffle with a box volume over 10x the vas.

So the plan now is to leave the 12" driver enclosure in my work room / office at the farm. A bit disappointing but at least I will get to hear them most days :dance: So what am I going to have at home in my small room ? Well I have been trying the small upper enclosure on it's own but pushed right back to the wall (the rear panel actually touching the wall). With the up and down firing 5" mid bass and four tweeters it sounds bloody marvellous and super clean -not an inch of bass overhang.

This will be the plan then. But they require getting the mid bass drivers as close to the back wall ass possible. Incidentally, with them touching the wall the 120 - 150 Hz suck out in my room has disappeared :dance: . The upper enclosure volume is about 14 litres when all the bracing and driver volume is taken in to account. The cube 3 speakers were in 8 litres so my enclosure is maybe a smidge too small but then I can't hear an audible bass hump like you get with an enclosure which is too small.

The raw 5" driver has a vas of 5 litres and qts of 0.45. When doped those figures will increase so 8 litres per driver sounds about right. Incidentally the cube 2 and cube 1 both seem to be under damped (qtc over 0.7) as the box volumes look too low. Especially the cube 1 where the box should be over 22 litres and it is in fact 17.6 litres. There will thoretically be a bass hump because of ths and a more rapid roll off in the low bass.

This would explain why going to cubix improves the bass so much. It will be tightened up and the low end will roll off slower so will go deeper as well. So why didn't Doc give the Cube 1 a bigger cab to start off with ? Well I can only assume that to keep the cube shape then the size would become too imposing. Cube 1's are already a 30 cm cube and they would have to be something like 34 cm cubed.

Oh well, all speculation. But why am i bothered ? Well I might add an 8 incher up firing in a lower enclosure to replace the one with 12 inchers. I can keep to outside depth and width of 30 cm (height about 44 cm) and I wont need to go isobaric. The uper enclosure will be a 30 cm cube which will be perfect for two 5 inchers. If i end up not needing the 8 incher then I will make a heavy stand for the 30 cm cube that does not impede the operation of the down firing driver. A lower cab of 44 cm height and upper cab of 30 cm height will leave a gap in the middle of 16 cm which will be adequate and give the whole thing a height of 90 cm which is about right I think. At 90 x 30 x 30 cm that shouldn't be too imposing especially compared to what the 12 inchers would require. Think of something the size same size as level 3 cubix or a floor standing cube 1.
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Drivers on opposing panels in push push configuration (bipole) = baffle step correction for free with no components in the signal path. A typical speaker level circuit for this consists of an inductor (coil) in parallel with a resistor (yuck). And a zobel is recommended across the driver (resistor in series with a capacitor :naughty: ) to flatten out any rising impedance. So four components added just for this. Plus it reduces the efficiency of your speaker which we don't want.

Put the speaker up against the front wall and bingo. This naturally baflle step compensated bipole double 5" speaker right against the wall can not be described as bass shy - it is full and surprisingly deep. Although they have a published Fs (resonance frequency) of 55 Hz when doped this will drop a fair bit. That's one of the reasons (along with being filter less and semi omni) I think makes the old cubes so full in the bass and large sounding for such small drivers and enclosures. The resonance frequency is lowered which is a nice side effect of the doping process :dance:

And having two 5 inchers dramatically reduces the distortion of these cheap Chinese drivers because they are sharing the work and not moving as much - these 5 inchers are £10 a pop if you know where to look FFS. So wiring them in series you get an extra 3 dB from doubling the radiating area but the doubling of the impedance seen by the amplifier reduces the current and so you are back to where you started. If you biamp the speakers though, you can wire them in parallel and end up 6 dB up overall :dance:

That brings you up to a level which is not far off that of the tweeter (90 dB), remember the doping has reduced the efficiency of these drivers which are only 84.5 dB to start with. Add more tweeters firing in different directions and the wired in series the level marries up very nicely with the mid bass and we can dispense with the padding resistor (12R :shock: ) It can only be good and with the tweeters sharing the work of one then they are producing much less distortion which is the main criticism of a first order filter on a little dome tweeter.

Having the xover frequency higher than average helps the tweeters as well. If you are crossing at 5 KHz and above which is what happens with these doped drivers and you combine this with sharing the work between several tweeters then the result is astonishing. Using a first order low pass (series inductor) on a mid bass would probably require a crossover frequency much lower (depends on the driver) as the inductor needs to roll off the driver in good time before the nasty break up modes cause a problem. They will still be there of course just at a lower level and because a first order filter only attenuates at 6 dB per octave (doubling of frequency). Could be problems.

I think the doping attenuates and smooths out these break ups very nicely. The downside of the 5 inchers and running them so high in frequency is that the driver starts beaming at a frequency determined by it's width. Speed of sound in cm divided by the width of the driver in cm = the frequency at which it starts beaming light a search light. In the case of a five inch driver this is about 3.3 KHz and it gets worse as the size of driver is increased. A 6.5" starts beaming at 2.6 KHz and a 8" at 2.1 KHz.

In a point and squirt speaker then this would cause problems as the directivity of the drivers is hugely different at the xover frequency, the mid bass is beaming and the tweeter is radiating at a much wider angle. Off axis would be a nightmare and as we get to hear that via reflections then a mess is the most likely result. But we like semi omni's and they work by reflecting most of the speakers output off all the boundaries in your room and they are not pointing right at you.

I don't know for sure but I think using reflections mitigates the effect or severity of this mid bass beaming. Semi omni's tend to keep much of their integrity as you move about the room although the very top end changes the most because of the tweeter firing forwards. Shove some more tweeters on and that is also mitigated. It can never be perfect though especially if you are much closer to one speaker than the other.

If you value pin point imaging more than anything then there is a good chance you will not like what I have created because that is not their strength. Don't try it if you are an imaging freak. What you need to do in that case is buy some Green Mountain Audio time coherent speakers that were designed by Roy who I quoted numerous times up thread. They are point & squirt of course.
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Anybody contemplating putting another mid bass on the opposing panel to the one which is there already then think again. The box enclosure volume needed doubles :cry: If you did it the bass would be awfully overblown with a huge peak in the response. You would have to build another box twice as big unless you get three more drivers and make two pairs in clamshell isobaric configuration.

But then you have two magnets facing outwards and that is not visually appealing. Add to that there is possibly a lot of nasty diffraction going on as the sound waves have to negotiate the basket and magnet. Can't say I have noticed that subjectively but it could be going on. Having the magnet out does modify the freq response because there is no dust cap facing out so if doing this to an existing design you would probably have to lower the crossover frequency. If doing a diy new build then this could just be taken in to account when picking the capacitor and inductor values.

Having one of a bipole pair of drivers flipped with the magnet out (as I have) is said to lower distortion as the irregularities of the drivers drive is cancelled out with one pushing and one pulling. I suppose if doing this subjectively with no measurements then it would have to be decided which is best and which compromise to take.

It is also said that a bipole with two identical drivers on opposing panels significantly reduces the vibrations in the box. This can only be a good thing, right ? This reduction in box vibration is also said to be increased if the two drivers are somehow mechanically coupled together. That would involve having the two magnets (if push push with both magnets in the box) mechanically coupled together. Several ways to do that if you are clever. Maybe a brace (at 90 degrees to the driver)which both magnets are pressing against firmly when they are mounted.

I have mentioned "it is said" quite a few times because I have read about these things all over the net (especially diyaudio.com) and having tried some of them I agree. But I have no measurements or evidence to back all this up so you will either have to take my word on it or decide to view what I have said as complete bollox. Your choice (who ever you are). :grin:
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

So, over 100,00 views of this thread now :dance: Either some one is interested or is having a laugh as a total speaker design noob blunders his way through the torturous process of trying to get good sounds out of cheap crap drivers and lumps of recycled ikea furniture chopped up with a chainsaw and attached together with gaffa tape and baler band.

91 pages and three years later, yet another twist to the story. and as always nothing is even finished :roll: 100 pages is gonna be easy at this rate. Do I get an award for filling 100 pages full of complete bollox ?

:text-banplz:
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