Mach One 4024, 4024A, 4029 Information and Upgrades!

[videolady201]

T/S vs LEAP

Are you saying that with losses you're going to get a 10dB increase in output? Sure, floor bounce is a known quantity. But how are losses adding another 4dB? I'm going to assume you meant pistonic above. If my equations assume pistonic movement then they would have higher efficiency than in the real world with losses.

First off as you have shown me I can show you. It's not floor bounce it is Half Space Gain. Now we need to agree we both have knowledge of speaker design and quit throwing stones at each others grammar and the words we choose. I know what floor bounce is but it is not the technical name or use and the VAS of the series driver/cabinet of which I listed is not technically correct. The point is I believe we both know what each other is talking about. It is a floor speaker, if it is designed anechoically it will not be linear as you set it on the floor, any floor, it will now have a 6db boost in all frequencies produced by the woofer until the power response start to close in on the woofer. This includes setting it down outside in a field. I have a mid driver that is a NAMM Audio 5" from a 24,000 DBL model speaker. You can run the T/S on it or use the factory specs and it shows it is 89db SPL. Now you run a raw SPL gated sweep and at 1w/1m. The average SPL is around 90db and in the 1khz range and a half octave on either side of 1khz, the output is over 105db. By standard T/S math you would say no way but that is what the driver produces in SPL output. These are the things that T/S can't show or predict. You and I both know why. This driver has very bad resonances at 1khz and is adding in phase to the electronic energy applied to the speaker. The loses I spoke about as you know are frequency dependent and very hi Q. The full specs of the mods on the driver are attached. Without me responding to the rest, please stop and check the math. I think you with see with the half space gain that they are 93db.

 

[dnewma04]

Just wanted to make the changes in the parameters clear for everyone to see where the differences between the modded and unmodded drivers lie. Notice that VAS is at ~1800l and the sensitivity is at 88dB. Substitute the original VAS published and sensitivity would be just under 83. If I can make one request, it would be to follow the standards that are out there, keep measurements consistent from measurement to measurement so data can be correlated.

Some of the data in the before and after are intriguing, I'm looking forward to the publishing of the mods so see how you were able to accomplish making the effective cone area larger.

 

[videolady201]

Cone Area

Some of the data in the before and after are intriguing, I'm looking forward to the publishing of the mods so see how you were able to accomplish making the effective cone area larger.

The cone area between the two is only 3%. One is listed as cm^2 and the other is listed as m^2. The one with the lower FS and increase in VAS is 3% larger because I included more of the surround in the cone area because it is now contributing more to the SPL as the cone is moving further.

 

[RayW]

I'm interested to see what the mods are too. It looks like the coil is changing as the Bl goes from 15.59 to 9.23. Assuming the magnet, top plate, and core don't change that means less wire length in the gap. But Levc goes up by a factor of 10 which would seem to indicate more wire in the coil. Sounds like going to a heavier gauge wire with a longer winding length. Is the Tier 2 a rebuild of the voice coil?

 

[videolady201]

Levc

I'm interested to see what the mods are too. It looks like the coil is changing as the Bl goes from 15.59 to 9.23. Assuming the magnet, top plate, and core don't change that means less wire length in the gap. But Levc goes up by a factor of 10 which would seem to indicate more wire in the coil. Sounds like going to a heavier gauge wire with a longer winding length. Is the Tier 2 a rebuild of the voice coil?

If you look at the first graph, the parameters Krm, Kxm, Erm, Exm, which is part of the TSL data, is set to 1 or 0 (unmeasured). On the second chart they are measured and do not have just a static entry. This is the reason for some of the differences. They define what the speaker is doing in the upper range of the Response. The voice coil in Tier 2 is not changed. Also, note these are two different speakers from different Mach 1s, 4029 and may be years apart and different production runs. Also, the 1st unit had stock foam on it and the second had been replaced.

 

[jamesm007]

IMO for what its worth ? This is VideoLadies Project. The project would lose coherency with a bunch of guys all jumping in giving there IMOs. It would be a continuous problem. Plus who owns a nice pair of MachOnes 4029s? If you don't own them a team working on concepts is just about the silliest thing I have ever heard. All members would have to own the MachOnes, as this can cost time and money if we try ideas... VideoLady has a project its hers/his we can follow or not, our choice. But we don't have to try to jump in or slow her/him down. Let the show continue... I say

Keep going VL and lets see how good the MachOnes are. Sorry I could not keep up.

 

[Copa1934]

For years the world believed that Bees can't fly, and yet the bees proved "science" wrong. There are those who will see this as a hint, and those that will see this as yet another chance to correct someone. The glass is half full, the glass is half empty. For me VideoLady is the glass half full and I'm just waiting to top off. Go VideoLady!!

 

[HomeBody]

It's been proven over the decades in many walks of endeavor-
Those who can't....critique.
It's all to clear that the multitude of questions come from those that have not contributed one once of cure for this speaker....save bad press that scatters across the globe.
Reminds me so much of the maligned .220 Swift.http://en.wikipedia.org/wiki/.220_Swifthttp://en.wikipedia.org/wiki/.220_Swift
The finest/fastest cartridge ever designed...birthdate- 1935...purposely maligned because of simple envy.

 

[dnewma04]

There is also a concept in leadership which contends that conflict is something that should be embraced as a positive thing and when it is, significant changes for the better can come about from it's existence. If everyone is always in lock step with the leadership, there is some potential being lost. It seems to me that most in this thread would view conflict in it's traditional negative sense.

Oh, and no scientist ever said a (bumble)bee couldn't fly, everyone could see that it could, but creating models to account for the constantly varying angles of attack, wing interactions at the top and bottom of the stroke, flow issues, vortex shedding and a few others. At some point, some lab assistant said "flight is impossible" based on using traditional aviation models but the same book that stated this, later explained that they understood that the vortices created would cause lift and explain the flight. This was well before high speed cameras and advances in computational physics which would have made the models much simpler to produce. So, I suppose some person (an engineer apparently) did claim they couldn't fly, but at no point did the scientists ever buy into the comment by the lab assistant, yet this story is clung to.

 

[nashvillebill]

IMO for what its worth ? This is VideoLadies Project. ....we don't have to try to jump in or slow her/him down. Let the show continue... I say

Keep going VL and lets see how good the MachOnes are. Sorry I could not keep up.

+1

I appreciate all the effort VL has put into this and would really like to see what can be done with the 4024a's.

Thanks videolady!!

 

[robmorin]

I have a headache now....

 

[RayW]

If you look at the first graph, the parameters Krm, Kxm, Erm, Exm, which is part of the TSL data, is set to 1 or 0 (unmeasured). On the second chart they are measured and do not have just a static entry. This is the reason for some of the differences.

Gotcha. :thmbsp:

Also, note these are two different speakers from different Mach 1s, 4029 and may be years apart and different production runs. Also, the 1st unit had stock foam on it and the second had been replaced.

Did you measure both of them before? It seems like that would aid in the repeatability. If they had different parameters at the beginning then they could have different reactions to the mods, depeding on what the mods are.

IMO for what its worth ? This is VideoLadies Project.

It certainly is. Nobody is trying to take it over.

If you don't own them a team working on concepts is just about the silliest thing I have ever heard.

Read the Indignia thread. It's a design by committee. Since it was a new speaker, nobody owned them. Despite that, the speaker turned out well enough that at least 26 pairs have been built now.

VideoLady has a project its hers/his we can follow or not, our choice. But we don't have to try to jump in or slow her/him down. Let the show continue... I say

Nobody is trying to slow down VideoLady. But, we are compelled to keep her honest. This thread will likely be read by many, many people. If it contains mistakes and/or misinformation then they will be learning it as truth. For instance, someone reading this thread up until the question Newman raised about the efficiency would think that the mod would decrease the Fs by 1/2 while increasing the efficiency by 5 dB. By that logic all you would have to do to get more bass out of any speaker is mass load it. The Fs would go down and the efficiency would go up. People would have 6" speakers in mini monitors hitting 120dB at 20Hz. Obviously that doesn't work.

It turns out, after the discussion, that the first efficiency number is the stock driver measured in free air and the second is in the cabinet in 1/2 space. That makes a big difference in the knowledge being absorbed by someone new to speaker design/modification.

Keep going VL and lets see how good the MachOnes are.

I agree, she should definitely keep going. However I would say that Mach 1's are what they are and she is finding out how good they can be.

 

[videolady201]

Measurements

Did you measure both of them before? It seems like that would aid in the repeatability. If they had different parameters at the beginning then they could have different reactions to the mods, depeding on what the mods are.

That would of been great but I could not, one of the surrounds had fallen apart, it had to be replaced.

 

[Copa1934]

I have a pair of Vieanna Acoustic Haydn speakers. Purchased around '05'. Like any small speaker I wasn't pleased with the bottom end, not that it's bad, just not deep enough or pronounced enough for the variety of music I listen to or for HT. I had two different subs, which worked nicely, but not always in balance, either too much or too little depending on source. The Haydn's replaced Mach Two speakers which had served me well till the foams gave up. I came across an ad for Mach One's and decided to get them, fullfilling a teen wish. Right off I had mixed feelings, outside of the fact that both pairs were heavily damaged in shipping, another story in itself. I picked the best two (no split seams or other leaks). I picked the best woofers which matched at 7.1 ohms ea. After head to head with the Haydn's, the Haydn's overall were superior, no question about it. My father loved to remind us that intellegence and common sense aren't the same things, often sighting the misguided efforts of those with gifted minds. Comparing a 30 year old speaker is like comparing a 1969 big block mustang to a 1999 Roush Mustang. Technology has changed, but let's not forget one vehicle is definitely older (keeping in mind only standard maintenance of the 1969, no new parts to keep it up to date, much like any speaker owner). So after some research I come across many posts about speaker fixes, like surrounds and even crossovers. Radio Shack was not a dedicated speaker shop, like JBL, Altec, Klipsh, or many others. Using what resources they had they arguably produced the best speaker one could buy for the money, as in the money back in that day. I bought and installed better quality caps and resistors and to my surprise the Mach One's kicked butt over the Haydn's in many, but not all, ways. I'm 51 years old, so arguably my hearing isn't as keen as it once was, but keen enough to "hear" the difference made by the minor fixes, and the improvement in comparison with a well known and well recognized speaker brand. I'm not out to prove to myself that the Mach One speaker is superior to speakers costing thousands of dollars, that would clearly put me in the no common sense arena. What I have proven to myself is that a 30 year old speaker, based on whatever technology and science was available (or leveraged by Radio Shack) produced a speaker that with little change could sound so good compared to a speaker costing 4 times as much and benefiting from so many improvements in design software, materials, drivers, etc. People own 1969 Mustangs not because they are the fastest, smoothest, greatest automobile on the planet, but rather nostalgia. But like any Mustang owner (which I own 2 presently) I enjoy driving my Mustangs, just as I enjoy listening to my Mach One's, not just for nostalgia sake. Would I enjoy my music more with more expensive speakers? Possibly. But given my budget, which must be divided between necessities and hobbies, the Mach One's and Haydn's do it for me. As stated before, look forward to minor tweaks to improve them further.

 

[jamesm007]

Great way to see things! I had my enjoyment its time for others to enjoy them. Its not all about sound quality... Those were the most awesome looking speakers back in the day; and they stood the test of time. They are still an awesome looking speaker!



But RS did tricked me for 30 years I thought it was a 4 layer VC flat wound. But if you look at the last catalog it does not say flat wire... Anyways 2 layers spread further up/down the coil is better for xmax and power-handling (but not round-wire).

I enjoyed them so much. Even if you don't do the mods enjoy them... sound is subjective. If you want to have a blast... you aint gointo blow those horns or woofer with a nice 100wpc amp, its all you need to lose your hearing.
Enjoy!

 

[Copa1934]

I dare the challengers to go out and buy enough speakers to build a pair of 3-way systems. Purchase the exact same components (same brand, model, etc.), but from different retailers (if possible). Construct your speakers and then test each in an anechoic chamber and tell me that each speaker system is absolutely dead on with the other. In a perfect world they would be. In reality each speaker system will have a real measurement that is in one aspect or another going to be different from the other. Raw speakers will have some variance not reflected in the supplied specs. The crossover components, while rated the same, may vary within there given tolerances. Something in the assembly process differed, bad joint, too much adhesive, inconsistent insulation, poor solder connection. In spite of following to the letter specifications fed into a modeling program, they don‘t turn out exactly right. And after all, isn’t that the point, going to all that trouble following the manufacturers specifications so that the outcome is, dare I say, predictable? All is not lost for those of us who don’t cling to hard facts and formulas, for our ears may not discern the faults. If these challengers are going to do things right, by all means test every driver you plan to use before assembling your final speaker system. That way you can ensure that each driver is mated with it’s own crossover, so that the final output will be near perfect. Good luck.

 

[Copa1934]

While I haven't gone to the trouble VideoLady has, I did notice variances even in specific models, like a couple sets of 40-4024a. Assembly variances, speaker impeadance differing between like drivers. Certainly not the best quality control. I would venture to guess that some things likely changed for economic reasons (i.e. profit). One example is the published Life Time warranty in the introductory catalog. In the following year catalog it was changed to 5 year, as was the number (40-4024a on the speaker) but remained 40-4024 in the catalog.

As for the mods, I've done caps and resistors (factory values) and boy did that wake them up. I'm tempted to experiment with different values on the caps, but not yet.

 

[RayW]

I dare the challengers to go out and buy enough speakers to build a pair of 3-way systems. Purchase the exact same components (same brand, model, etc.), but from different retailers (if possible). Construct your speakers and then test each in an anechoic chamber and tell me that each speaker system is absolutely dead on with the other.

That's not too much of a dare. I do that for a living. Yes, I've done the changeover from different driver vendors. I know what is involved. I'm not saying test every driver before doing the mods. However, when a difference in Levc of a factor of 10 shows up, that should send up some flags. VL answered that it was because one of the was not actually measured so the program filled it in. No worries.

However, not knowing where you're starting from means that when you get to the end you can't retrace your steps. If there were, in fact, 2 different woofers that were used in the 4029 and the modifications are designed around 1 of them then they may not work out as well for the other.

Usually in a scientific environment you measure, then change 1 thing and measure again. Then change 1 thing and measure again. This assures repeatability and easy to follow documentation. VideoLady is going at it from a different angle. She's got a goal in sight and what matters is getting there. That's fair. The problem is that when she says the goal is 11Hz Fs then you have to measure for that. If she did it by adding 50g of mass to the cone that's great. But if you don't have the same driver she does then adding 50g of mass may or may not get you to the 11Hz Fs. If you don't start at the same place she does then taking her route may not get you to the same destination. That's why I asked about the specs on the modified driver before the modifications.

 

[videolady201]

The Song Remains The Same

Usually in a scientific environment you measure, then change 1 thing and measure again. Then change 1 thing and measure again. This assures repeatability and easy to follow documentation. VideoLady is going at it from a different angle. She's got a goal in sight and what matters is getting there.

1..There are parameters in a driver that are sensitive to change and others that are not. Example: Two identical drivers, voice coil wire gauge is the same, number of turn, winding length, etc. Cone shape, weight, material. All things the same a far as hands on examination is concerned but two completely different sets of parameters. This has happened in our production testing a few times through the years. It all came down to the permeability of metals in the top plate and the pole piece of the magnet steel. Point is no driver change is required to get different results, just one error in the production of a single piece that would otherwise, upon physical inspection would appear to be the same. :scratch2:

2..The cabinet being Acoustic Suspension and of a very hi Q in this case, provides the largest portion of the compliance load for this driver. Even with changes up to a 30% mark, has almost no affect on the output.

3..You don't know what my goal is and I prefer to speak for myself and would appreciate it if you didn't try to do it for me.

 

[dnewma04]

Please stay on topic. Leave the challenges to a new thread.