I'm up to $260.92 for this project including all the board, driver, paint, binding posts, poly fill, 50ft 12awg wire and everything
Sorry no updates recently. I'm just sealing the paint with a clear satin clear coat. its taking a day to dry then i'm sanding it and putting another coat on. its looking devine. I'll post a new picture when I get the whole thing coated.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
First coat is on top. sides are sanded lightly and waiting for their final coat. I'll probably sand the top once more and then hit it one more time. Then It will be done
See my previous post.
You can get a lot more excursion without worrying about power levels when the drivers are free-air.
Since its about exercising the suspension for a bit, that's what I'd recommend.
FWIW, I like 15 Step by Radiohead, though Bass I Love You really gets cones wobbling.
Usual disclaimer: if you decide to run the driver at full-power without a cabinet, you're likely to destroy the driver. Keep the power input sensible, <100w.
Chris
First, is there any evidence that breaking in drivers makes them perform better?
Second, what is the significance of going to the extremes of excursion if such extremes are unlikely to be achieved during normal playback? That would imply permanent changes happen once you hit Xmax, which I doubt has precedent.
Undeniable loads of it. Performing "better" is not what you are concerned with. It's the linearity and behavior of the suspension that changes with time. A large mass with a high amount of stiffness to keep it controlled (read: subwoofer) means that after repeated use, K, the stiffness, becomes a decaying function of time. In other words, the stiffness of the suspension will begin to drop as the driver is used until it reaches a steady state condition in which you have a new driver resonance.
Fs can easily change by 20% from new to even 40 minutes (yes, minutes) of large excursion in free air. You just need to think about what you're using as a suspension. Linen and rubber both have self compliances. They do not have infinite resilience, so at some point their elasticity will rise when they're subjected to force. Any mass/stiffness system has this characteristic.
Where are the undeniable loads of it, and why would I care if it didn't make the system perform better? Not only do you need to prove that there is a significant change in the behavior of the driver (either statistical or quantified proof), but that it has an audible and significant positive effect over the long-term.
Are we on audioasylum or diyaudio?
I'm surprised people still discuss this, as if it was actually under debate. Drivers are mechanical devices, with moving parts that wear, just like anything else.
http://www.gr-research.com/burnin.htm
http://www.gr-research.com/burnin.htm
Suspension gets looser, Fs drops. T/S parameters are now stable, and more likely to be inline with the manufacturer's specs.
Why design a cabinet for the driver's initial state if the T/S parameters are going to shift?
Chris
Simply because as they shift, they shift in complementary ways, i.e. reference efficiency changes too little to matter. If a driver shifts enough from published specs to require a different alignment, then the manufacturer has either changed its specs without updating its docs and/or is playing the age old marketing 'numbers game' like we see from Pyle, MCM, etc..
If they shift too much from initial to 'broken in', then to my way of thinking, they are defective.
Consider Lowther, with many folks claiming it takes 250+hrs break in time. This is just plain broke IMNSHO. If this is where they need to be, then they should design it in.
GM
I wonder if there's anything spiders and surrounds could be made of that was still affordable, but would never deteriorate in any way? Carbon fiber?
Drivers made with the same standards as say...parts on the Mars rover...would be pretty awesome indeed...but I think only Warren Buffet would be able to afford such a speaker.
Drivers made with the same standards as say...parts on the Mars rover...would be pretty awesome indeed...but I think only Warren Buffet would be able to afford such a speaker.
Well, they could be dirt cheap, but the trade-off is a near zero Xmax.
A Lansing/Altec field coil 515 [or similar construction] with its continuous diaphragm/rolled paper surround and spring coil spider has many times shown little/no shift over the decades after heavy abuse in cinema sound apps, but basically has no Xmax, same as most vintage compression drivers, just a smooth power compression curve with increasing power.
For most HIFI apps then, if you start with an efficient system, then this type of construction is still a viable option since most music is heavily compressed and why folks are usually pleased with even fractional Xmax Fostex or similar horn drivers in reflex alignments.
This high efficiency pays dividends in lower distortion, extracting any low level/'inner' detail in the better recordings, making for a more accurate reproduction with the trade-off of course being that bad recordings can be downright unlistenable.
For those that must accept a small speaker, then omitting the spider is the way to go as it allows much more surround design flexibility among other things.
Babb did this on at least one driver, the Lorelei, which resulted in a water-proof, powerboat app rated [AFAIK] ~4.5” effective diameter, 1” Xmax, 400 W long term tested peak power capability, ~23-20 kHz flat power response over circular ~140 deg in a 1 ft^3 I.B. alignment!
He was selling them during the prototype stage for $849?/pair, so figure at least 2x this had it gone into production, but still……. This sort of performance at < Lowther prices?
The trade-off of course was a low efficiency, though it didn’t sound like such and with a calculated mid band 86+ dB/m, no lower than some of the seemingly stupid priced ‘audiophile’ bookshelf speakers.
Another was no repairs could be made to it and had no trade-in value beyond what a metal scrapper would give you. Fortunately, it was so robustly built plus with then SOTA multi layer VC design/construction that dropping it or similar wasn’t likely to damage it AFAIK beyond dinging its grill/reflector, though this would alter its polar response.
DC Gold bought out Babb and supposedly sells/sold a variant of it, though have seen no design details to verify this, but last I checked, nobody was home, so guess the economy took out the most advanced, promising driver that’s come along since the original 1976 Babb patented design.
Scaled up to 12” – 21” sizes would obviously cost more in materials/tooling and weight would probably be prohibitive for any portable app even if the lower efficiency was acceptable, ditto cost for all but maybe large high end HIFI/HT apps, so figure 8” would probably be the practical limit for what is basically a compression driver design with a small/short WG.
GM
A Lansing/Altec field coil 515 [or similar construction] with its continuous diaphragm/rolled paper surround and spring coil spider has many times shown little/no shift over the decades after heavy abuse in cinema sound apps, but basically has no Xmax, same as most vintage compression drivers, just a smooth power compression curve with increasing power.
For most HIFI apps then, if you start with an efficient system, then this type of construction is still a viable option since most music is heavily compressed and why folks are usually pleased with even fractional Xmax Fostex or similar horn drivers in reflex alignments.
This high efficiency pays dividends in lower distortion, extracting any low level/'inner' detail in the better recordings, making for a more accurate reproduction with the trade-off of course being that bad recordings can be downright unlistenable.
For those that must accept a small speaker, then omitting the spider is the way to go as it allows much more surround design flexibility among other things.
Babb did this on at least one driver, the Lorelei, which resulted in a water-proof, powerboat app rated [AFAIK] ~4.5” effective diameter, 1” Xmax, 400 W long term tested peak power capability, ~23-20 kHz flat power response over circular ~140 deg in a 1 ft^3 I.B. alignment!
He was selling them during the prototype stage for $849?/pair, so figure at least 2x this had it gone into production, but still……. This sort of performance at < Lowther prices?
The trade-off of course was a low efficiency, though it didn’t sound like such and with a calculated mid band 86+ dB/m, no lower than some of the seemingly stupid priced ‘audiophile’ bookshelf speakers.
Another was no repairs could be made to it and had no trade-in value beyond what a metal scrapper would give you. Fortunately, it was so robustly built plus with then SOTA multi layer VC design/construction that dropping it or similar wasn’t likely to damage it AFAIK beyond dinging its grill/reflector, though this would alter its polar response.
DC Gold bought out Babb and supposedly sells/sold a variant of it, though have seen no design details to verify this, but last I checked, nobody was home, so guess the economy took out the most advanced, promising driver that’s come along since the original 1976 Babb patented design.
Scaled up to 12” – 21” sizes would obviously cost more in materials/tooling and weight would probably be prohibitive for any portable app even if the lower efficiency was acceptable, ditto cost for all but maybe large high end HIFI/HT apps, so figure 8” would probably be the practical limit for what is basically a compression driver design with a small/short WG.
GM
My friend, I take it you do not work with loudspeakers or driver test equipment regularly. The fact that it surprises you that a stiffness element will gain compliance with time and wear says that you don't truly understand the physics behind how drivers work.
They are electromechanical transducers, and any component containing stiffness which undergoes repeated loads and stresses will eventually deform even if slightly. No one, especially not me, has said the performance will be greatly enhanced. I believe you are equating electrical burn in with mechanical break in. Mechanical break in is not fiction, and it's simply because of marketing personnel that it gets a bad reputation.
Why would you care? That's up to you and you alone. 🙂
This is true 100%. No competent transducer engineer would claim that their driver is definitely superior after it's broken in. If that's the case, then choose a more compliant yet more resilient suspension material. The point is that the parts undergo stresses which can easily cause the spider to relax especially if driven at high excursion levels for break in (as it should be done).
The playing pink noise for 100 hours when making the drivers move +- 1.5mm is not the same thing. This is marketing to cover for a design which sounds different in a show room than in a living room, after which time you'll become accustomed to the sound of the speaker and claim it's "broken in".
Meh, it's really not too big of a deal IMO, the change is usually measured in single-digit percentages, which I'd imagine is well withing the tolerances of any crossover components or cabinet design. I don't regularly see people worry much about corner correction in folded horns, or measure vents with micrometers sanding off fractions of millimeters, or measure stuffing for cabinets out to two decimal places of weight, so it's really all just...yeah, break in happens..drop your port tuning 2 or 3 cycles from what you figure from published specs, but beyond that, don't worry about it..it'll still be within the tolerances of all but the most expensive tight-tolerance equipment being used with it anyway.
And on that note....
And on that note....
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Hahahaha so true dr dyna!! This was a build thread. Now everyone is arguing about speaker break in and have yet to prove with evidence and reports why it is or is not better to break a driver in. Imo the 2 hours I have played this sub it has gotten a little louder than at first and it simply sounds clean sharp and good. Its loud but in my opinion I need another 15" ultimax to flatten the response in my room. If I ever get a bigger house im definitly going with 4 x 18" IB driver for movies. But for all around use this ultimax I have is awsome and im thrilled all for your 260 bucks. Not bad!!!
I think you misrepresent my position. I am not surprised that the possibility exists, and I think you will you have some difficulty proving that indeed I have claimed otherwise. However, I do not give much thought to it as you have yet to show that it makes a whit of difference to break in his driver in free-air instead of in the enclosure.
I should remind you that your very first response to me was that (I paraphrase) "there are undeniable loads of evidence that breaking in drivers makes them perform better". What this has to do with free-air break-in I do not know, and I am sorry I let this go so far in the first place.
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Awesome, yeah, the most important thing is that you're happy with it. As far as break-in being bad or good, it really isn't either....it just happens. It won't be so much of a change in either direction to be significantly different, unless you have a driver with..lets say a 45hz FS, which might be a little "light" on the lowest E of a bass guitar...but after break in, you're getting another DB or two and now that 41.2hz note shines a little brighter.
With the tunings we're talking about for an Ultimax 15, and with the size of the enclosure you've got, we're into EQ to get it down that low anyway, so it's (imho) not really something I'd worry about much in your circumstance.
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