Excellent. The first 2 graphs illustrate exactly what i meant.
I am no XO expert but simply looks like an added Zobel.
dave
I have liked the Heresy model from long ago. one thing that stupefies me is why O why would you ever mount any driver behind the baffle?
In a similar vein, I bought a pair of Cornwalls many years ago, with the drivers all mounted behind the baffle. It wasn't easy for me, but I took them all out and worked with the one power tool that I owned at the time, i.e. a Dremel. For what seemed like way too long an effort, I got all of the drivers mounted in front of the baffle. I cannot tell you that it was a day and night difference, but I would do it again.
Many years prior to that, I built the corner horns. You can guess where I mounted those drivers (except the 15" bass driver!)
Many years prior to that, I built the corner horns. You can guess where I mounted those drivers (except the 15" bass driver!)
More than sufficient, thank you so much. I think I have the E, because my two caps look identical, and I see labeling on one "2uf".
I'm informed to try some things now, things I can always undo easily at least.
Thanks again,
Loren
I'm informed to try some things now, things I can always undo easily at least.
Thanks again,
Loren
One more question, please. In the ALK schematic Marcus posted, and I'm attaching again here...The caps and resistors I have. The autoformer gets reused. The inductors are all new. How should I wind these? I see to use solid wire for some (magnet wire right?), and Litz for others, but I'm not sure how large of a gap to wind them on, or, if other types of cored inductors would work as well.
Thanks everyone
Thanks everyone
Hi,
mounting from behind is cheaper and easier than making a recess for the driver, so a cost cutting thing in one perspective. Also, there is possibility to clamp the driver from magnet and decouple it from the baffle, affect diffraction/radiation pattern, moves acoustic center back a bit, perhaps other things, so there is performance perspective to it which side the baffle the driver is mounted. Also the hatch needs to be considered, there must be one to install the driver. Perhaps there is one anyway used for other purposes. There is also visual aspec to it.
Like anything, mounting driver from from behind baffle is not universally best, or most cases even advisable, but would be perhaps nice, or even the best, option for few applications. On this heresy case it seems to be ease of manufacturing, so a cost cutting measure, also the front is easier to make (the protective fabric). Judging by eye they didn't pay any attention to diffraction, or sound of the box in general.
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The ALK crossovers typically used commercially available air core inductors, like those available from Parts Express, for example. Litz wire can be a beast to solder unless you have a solder pot.
Here's photo of an ALK crossover:
Here's photo of an ALK crossover:
tmuikku,
Thank you for your response and perspective. I appreciate the observation of cost being reduced for manufacture, as evidenced by the driver mounting and the enclosure in general. After all, look at the times in which these were made and then compare them to other manufacturers of that era. That much I can certainly appreciate. So now, we are going to take a classic design worthy of upgrades by spending time and money on the crossover, which of course has been successfully demonstrated by the resulting curves after that is done. Makes perfect sense to me. Then the cabinet is being damped with use of cotton blankets or some such. Another great idea that I would readily do myself. There is no reason not to remount the drivers properly by todays practices, especially when you consider what amounts to a very poor horn extension by the baffle depth for the tweeter. The midrange (squawker, I love that term) is very likely affected by this same problem. I cannot say about the bass driver so much, but if it were me and I were to leave it on the backside, then a chamfer would be made in front of it.
Yes, I do remember having to 'adjust' the fabric panel of the Cornwalls after making these changes, but it is just part of the process and result looked to be 'factory' when complete. One thing that I would not do again was the adding of L pads to the midrange and tweeter, but that was my thinking 30 years ago.
Thank you for your response and perspective. I appreciate the observation of cost being reduced for manufacture, as evidenced by the driver mounting and the enclosure in general. After all, look at the times in which these were made and then compare them to other manufacturers of that era. That much I can certainly appreciate. So now, we are going to take a classic design worthy of upgrades by spending time and money on the crossover, which of course has been successfully demonstrated by the resulting curves after that is done. Makes perfect sense to me. Then the cabinet is being damped with use of cotton blankets or some such. Another great idea that I would readily do myself. There is no reason not to remount the drivers properly by todays practices, especially when you consider what amounts to a very poor horn extension by the baffle depth for the tweeter. The midrange (squawker, I love that term) is very likely affected by this same problem. I cannot say about the bass driver so much, but if it were me and I were to leave it on the backside, then a chamfer would be made in front of it.
Yes, I do remember having to 'adjust' the fabric panel of the Cornwalls after making these changes, but it is just part of the process and result looked to be 'factory' when complete. One thing that I would not do again was the adding of L pads to the midrange and tweeter, but that was my thinking 30 years ago.
Awesome that does it. Thank you both. Spent an hour and a half searching...holy cow they've gotten expensive. Surely better to wind my own, right?. But everywhere I looked for enameled wire was about the same at $45-50 per 100ft 12ga enameled. For the 12awg 1.3mH alone I'm looking at about 240'. Anyone have a suggestion, maybe somewhere to shop in bulk? Or, would it likely be OK to use insulated wire with the thinnest jacket I could find?
Tmuikku and Ixnay- Surely someone has done this with one of the older Klipsch models and has taken measurements? They all sound like valid points with the woofer and horns. But quantitively, how much of a difference does such a thing make, keeping baffle size and placement the same? A few of you have got me thinking of the value these Hereseys hold, simply because of being so clean and all original. Otherwise I'd have already tried this-
Loren
Tmuikku and Ixnay- Surely someone has done this with one of the older Klipsch models and has taken measurements? They all sound like valid points with the woofer and horns. But quantitively, how much of a difference does such a thing make, keeping baffle size and placement the same? A few of you have got me thinking of the value these Hereseys hold, simply because of being so clean and all original. Otherwise I'd have already tried this-
Loren
I guess that this is equal to how far do you want to take a classic car for either renew or rebuild. Some will be willing to look up the original paint formulation and go all the way from there to the other end to keep the originality. Of course on the other end are those who would chop the chassis and do what they damned well pleased. Somewhere in the middle is the guy who has the intent of keeping a lot of the design original but perhaps adding some performance benefits. Nothing that stands out too much, but an enhancement in performance non the less. This is exactly where you stand with this project. It is honorable to keep as much as possible of the original design, unless that design is lacking for your listening purposes. Seeing as though you are willing to refresh the crossover with newer, and maybe even better performing parts, then it would follow that the simple adjustment of driver placement from rear to front baffle (with appropriate rebate if also desired) will make just as obvious of an improvement in dispersion as was improved by all of the new crossover components.
The one thing that I would not be clear about is the rewinding of inductors rather than reusing the originals. I likely missed it if the values are being changed, and if so, if they are less than the original, the inductor could just be unwound to the smaller value, thus saving you the cost of a new inductor. In the case that they need to be of a larger value, then the likely answer is to have one bought off the shelf. I don't suppose that I would go all the way and buy an exotic type, such the ones that may be using square wire or flat ribbon wire, but instead a decent inductor from Solen or Parts express may just the ticket.
The one thing that I would not be clear about is the rewinding of inductors rather than reusing the originals. I likely missed it if the values are being changed, and if so, if they are less than the original, the inductor could just be unwound to the smaller value, thus saving you the cost of a new inductor. In the case that they need to be of a larger value, then the likely answer is to have one bought off the shelf. I don't suppose that I would go all the way and buy an exotic type, such the ones that may be using square wire or flat ribbon wire, but instead a decent inductor from Solen or Parts express may just the ticket.
I would preserve their construction as is, I mean : doing nothing that could be damageable, irreversible...
Conversely to yours, my Heresy I HBR were not so nice, so I had to make them presentable :
T
Other than the use of a parallel resistor across the autoformer, I'm not a fan of ALK's crossovers. All his measurements were voltages across resistors...unrealistic. His woofer filters were based on his thoughts that the inductance of the driver should be subtracted from the woofer inductor. A type E2 has a 4mh series inductor followed by a 33uf shunt capacitor. Above he somehow determines that the inductor should be 1.3mh. IMHO that crosses the woofer way too high. Litz inductors are a waste of time and money...again, IMHO.
Mboxler- Agreed all the inductors can be solid wire, the litz wire seems like some "audiophile trick". I'm also wondering about that one feeding the woofer, as there's no reason it should have to be 12ga. wire just to support up to 100w. I was looking at a chart yesterday and I think even 14 or 16awg should be plenty large enough to handle all the power these could ever take anyway, and definitely enough to handle any tube amp they'd ever be paired with. But as for value I didn't think it was too far off. Original in these type Es is 2.5mH, but that's without the parallel cap at woofer. I figured 1.3mH was what worked because ALK took that parallel cap to 39uf (and that there I could probably use one of my many motor run 40uf caps. Still need to find a good source for winding my own either way. Thanks,
Loren
Loren
As another point of reference, E2 Crossovers used 4.0 mH and 33 uF on the woofer. There are other reasons to use larger gauge wire than just ultimate power handling. Too much series resistance will effectively destroy any damping factor your amp may have.
I agree...12AWG is overkill and expensive. In fact, ALK moved from air core to iron/steel core woofer inductors a long time ago.
When one moves from a first to second order low pass, the inductor value must increase to offset the lower impedance the shunt capacitor creates at lower frequencies. Otherwise the FR of the woofer will overlap the FR of the squawker.
When one moves from a first to second order low pass, the inductor value must increase to offset the lower impedance the shunt capacitor creates at lower frequencies. Otherwise the FR of the woofer will overlap the FR of the squawker.