Need help making custom subs/monitors

[Dark Ice]

The wedghorn was not designed for fidelity. It was designed to get loud and be portable. That's what it does. There are options in the plans for higher fidelity. FWIW piezo tweeter arrays have been used by EAW and Meyer with varying degrees of success. Piezos in singles or horizontally arrayed sound like crap. A proper vertical strainght or crossfiring array can sound extremely well. David Perry built the DR290 and compared the piezo array to an array of JBL compression drivers. Read the entire saga here: http://myweb.tiscali.co.uk/prosoundhire/dr290%20review.htm

 

 

I cant find any mention of a piezo on that page, do you have links to any more research on making piezo transducers sound acceptable for SR purposes? I'd be very interested to read more. The piezos depicted on the wedgehorn look identical to the ones I see on cheap wedges, and I have absolutely no interest in using them for anything, sounding as they are.

The wedge itself however looks like it would be an amusing little summer project if it could sound decent (what are the high fidelity options? Do they resolve that massive dip in response right in the upper vocal range?).

 

Steve.

[Craig Vecchione]

 

Sigh...

 

 

Oh, and now the resigned condescention. I suppose this is "unintentional" too.

[Craig Vecchione]

 

Les

 

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[Craig Vecchione]

 

 

...

[preacherman672]

I cant find any mention of a piezo on that page, do you have links to any more research on making piezo transducers sound acceptable for SR purposes? I'd be very interested to read more. The piezos depicted on the wedgehorn look identical to the ones I see on cheap wedges, and I have absolutely no interest in using them for anything, sounding as they are. The wedge itself however looks like it would be an amusing little summer project if it could sound decent (what are the high fidelity options? Do they resolve that massive dip in response right in the upper vocal range?). Steve.

 

 

 

Sorry about that, the link to the piezo array he tried is in this review:

 

http://billfitzmaurice.com/phpBB2/viewtopic.php?t=1924&highlight=

 

 

Better fidelity is achieved with different array options. The Wedgehorn 10 has better options for higher fidelity. It is however quite a bit larger. The fidelity options help the frequency response but they will still need some EQ.

 

Les

[agedhorse]

IF dado construction is used with the same adhesive, it is stronger and just as airtight. If it is used with Elmer's type wood glue it absolutely is not. I have used both extensively.

 

 

A dado joint is stronger, even with carpenter's glue(s). Way stronger, especially in sheer.

 

 

The misleading hype comes from the speaker manufacturers and speaker designers like yourself. And is unfortunately rampant on most forums like this.

 

 

I agree that some manufacturers, especially those selling to the uneducated and uninformed, capitolize on selling numbers, grossly inflated numbers. It's the old "dress for show, not for go" marketing" I would appreciate that you do not include me in this statement. I have consistently commented on the real world versus marketing world approached and have been probably the most conservative forum member on this topic.

 

 

Would love to. Eminence placed a recall on the HL10-C (at least get your facts straight that far). Faulty batch of drivers.

 

 

I know enough about this to say you do not have all the information. Unfortunately, I can't go into depth here, though I would like to.

 

 

Complete crap. Bill has never recommend over rated RMS wattage for any driver in a tuba, regardless of how high the power rating was. If others on the forum recommend it, Bill points out the problems immediately.

 

 

Mr Crooks and others have recommended 2xRMS and greater and I have not seen Bill jump in to moderate this. In fact, ithere was some bragging about bridging large amps into the Tubs with blind-foolish pride. One of these guys then came back with blown drivers... blaming Eminence of all things!!!

 

 

The problem with your jocularity on the subject is that once again, the heat sink has been tested and proven to work. It's design was for rental gear that had the oppurtunity to be overpowered by renters. Once again, at least try to get your facts right.

 

 

The heatsink is not a solution for the mechanical damage that occures with the overpowering. It will (maybe) reduce the pole piece temperature a few degrees, but thermal failure mode is rare in a subwoofer driver. It is about 90% due to mechanical causes. Not to mention the effects that added restriction will have on the mechanical parameters of the driver itself.

 

 

Bill has never claimed any magic. His boxes outperform most commercial boxes, period. A-B testing has been quantified. Sigh....same old rhetoric. The design has been measured quantitatively by independent sources.

 

 

I had the "pleasure" of listening to somebody who had a couple of TUBA 24's (that's what they looked like, but maybe they were 30's) a side and you know what... they sounded like one note bass, and not very impressive at that. They did about what I would expect they could do... ok for what they were but nothing like the pro boxes I work with, nor those that tour through our venue either. Granted, the sound guy and Tuba owner may have liked the sound but it was not what I would consider inmpressive for a box of that size or complexity.

[tlbonehead]

Dado construction with adequate glue is superior to "dead-rec'oning" butt joints in all ways, except for lack of precision. The gripe I have is the rediculuous comparison to real pro boxes, and the forum member's assertion that the performance is superior in all aspects. It's just misleading hype, stuff that is unfortunately rampent in almost all DIY forums. Care to discuss the high Eminence driver failure rate in the Tuba subs? (HLA=10). It was particularly fascinating to follow the failures that went hand in hand with the rediculuous recommended power handling recommended by several of your vocal forumites. I looked at that and saw immediately that they had no understanding of the failure modes and the dynamics of the failure process. The heatsink thing was particularly amusing in that it addressed the wrong failure mode parameter to begin with. If you don't understand the problem, you sure as heck don't understand how to develop a proper solution. I's an "ok" box, for an "ok" cost (less labor of course). Nothing particularly wrong, but nothing revolutionary or magic either. It's just another possibly reasonable solution for some applications. By the way, any time I hear claims that a speaker (based on claimed sensitivity curves in half-space) is producing sound at cloae to 50% efficiency (or corrected for sensitivity-dispersion curve) the bull{censored} alarm goes off. It just ain't gonna happen. This is like the chemist that claims to have discovered how to make gold out of lead, or has just developed a new perpetual motion machine.

I'm working on my cold fusion thing currently. Whaddya think?

[preacherman672]

 

Originally Posted by preacherman672 View Post Sigh... *all* speaker drivers will demonstrate varying impedance across their response. They will also impose varying inductive loads. You specifically talked about nominal loads. So are you going to state that only a horn-loaded box imposes mechanical loading on a cone driver? That such loading is greater than the combination of pneumatic loading and unloading, and resulting intertial forces on the cone of a sealed cabinet? Certainly these factors all vary, but to use that as an excuse to dispute a side-by-side comparison is going a bit over the top. Yes, I will say that Bill's horn loaded boxes impose more mechanical impedance on a speaker system. Repeated impedance sweeps prove this. But I compared a 4 ohm cabinet with a pair of 8 ohm cabinets...a 4 ohm load. But I can't do this, so you say. So, do tell, how would one go about fairly comparing a pair of Tuba-24's with an SR4719X? Certainly the response charts on Bill's pages, which are cited to such a great extent as a comparative tool, say nothing whatsoever about the testing parameters used, or that these 8-ohm cabinets aren't really 8-ohm cabinets and can't be tested as such. Once again the TESTED impedance of a Tuba is 12 ohms with an 8 ohm driver. This is not an assumption or a prediction. It is a tested fact. It is also all over the forum and in every set of recent plans. It was not something that was designed, it was something that was discovered in development. You've never been in a small club where you had little room to even fit your rig, let alone place speakers for optimum output? You're really trying my patience. Yes I've been in a bunch of them running sound, probably more than you. Most stages are against one wall, I've rarely ever seen a stage in the middle of a small venue. Wall loading the subs would then be the best option, corner loading being the next best.

 

 

Les

[preacherman672]

A dado joint is stronger, even with carpenter's glue(s). Way stronger, especially in sheer. Simply not true. Carpenters glue is much more brittle and has little or no flex. The glue will break if the joint is flexed any at all. Many the cabinet drawer in kitchen/bath has fallen victim to this fate. If this happens in your speaker cabinet it will break the seal and cause an air leak. I agree that some manufacturers, especially those selling to the uneducated and uninformed, capitolize on selling numbers, grossly inflated numbers. It's the old "dress for show, not for go" marketing" I would appreciate that you do not include me in this statement. I have consistently commented on the real world versus marketing world approached and have been probably the most conservative forum member on this topic. Until it comes to DIY. Then you repeatedly say how something cannot be so even when the tested results prove you wrong. I know enough about this to say you do not have all the information. Unfortunately, I can't go into depth here, though I would like to. So we are supposed to trust your "secret info" when we have direct confirmation from Jerry at Eminence? And you say I should not include in the group of misleading people? Mr Crooks and others have recommended 2xRMS and greater and I have not seen Bill jump in to moderate this. In fact, ithere was some bragging about bridging large amps into the Tubs with blind-foolish pride. One of these guys then came back with blown drivers... blaming Eminence of all things!!! Once again you fail to get all the info. Bill and Leland both recommend a 2X power rating ONLY if you have a limiter in the system to limit the input and keep the wattage to RMS. If only you read more you would find this in the sticky section of Bills forum. The heatsink is not a solution for the mechanical damage that occures with the overpowering. It will (maybe) reduce the pole piece temperature a few degrees, but thermal failure mode is rare in a subwoofer driver. It is about 90% due to mechanical causes. Not to mention the effects that added restriction will have on the mechanical parameters of the driver itself. The heatsink was designed to work over a time based interval with heavily compressed music, which is what would occur in most DJ cases. I had the "pleasure" of listening to somebody who had a couple of TUBA 24's (that's what they looked like, but maybe they were 30's) a side and you know what... they sounded like one note bass, and not very impressive at that. They did about what I would expect they could do... ok for what they were but nothing like the pro boxes I work with, nor those that tour through our venue either. Granted, the sound guy and Tuba owner may have liked the sound but it was not what I would consider inmpressive for a box of that size or complexity. This is where your duplicity is showing. If someone came onto this forum and said. "I heard some JBL SRX that sounded like crap." or "I've heard a bunch of Genz-Benz that sounded bad." , you would immediately counter with something to the effect that operator error must have caused it. But your one experience listening to someone else's speakers couldn't be operator error though, must be crappy speakers

 

Les

[Craig Vecchione]

 

Yes I've been in a bunch of them running sound, probably more than you. Most stages are against one wall, I've rarely ever seen a stage in the middle of a small venue. Wall loading the subs would then be the best option, corner loading being the next best. Les

 

 

Amazing how you think you know how many clubs and bars I've been in. How does one gain such clairvoyance, and does the condescention come with it as a package, or did you have to get that separately?

 

As if it's actually necessary to explain this yet again, the great majority of bars and small clubs, venues appropriate to a Tuba-24, have no stage. The waitresses clear out a few tables, and the band sets up on the floor. It may be in a corner, or half-buried in an alcove used for private parties, or it may be along the middle of a wall. In any case, the subs are going under the mid-highs, as they are the means of elevating same, and the stack sure as hell isn't going behind the front line of mics in order to place it against a back wall, let alone against a back corner or both sides of the room. Even a proscenium style theater will often preclude optimal placement because the stage extends considerably from the proscenium and corner placement puts the mics in front of the stacks.

[preacherman672]

Amazing how you think you know how many clubs and bars I've been in. How does one gain such clairvoyance, and does the condescention come with it as a package, or did you have to get that separately? No clairvoyance needed. I work for a soundco and run sound regularly, you do not. No condescention intended. As if it's actually necessary to explain this yet again, the great majority of bars and small clubs, venues appropriate to a Tuba-24, have no stage. The waitresses clear out a few tables, and the band sets up on the floor. It may be in a corner, or half-buried in an alcove used for private parties, or it may be along the middle of a wall. In any case, the subs are going under the mid-highs, as they are the means of elevating same, and the stack sure as hell isn't going behind the front line of mics in order to place it against a back wall, let alone against a back corner or both sides of the room. Even a proscenium style theater will often preclude optimal placement because the stage extends considerably from the proscenium and corner placement puts the mics in front of the stacks. Speaker stands work great here. Use speaker stands for the tops, place subs against the wall. Easy and simple and done quite often.

 

Les

[Craig Vecchione]

Originally Posted by agedhorse A dado joint is stronger, even with carpenter's glue(s). Way stronger, especially in sheer. Simply not true. Carpenters glue is much more brittle and has little or no flex. The glue will break if the joint is flexed any at all. Many the cabinet drawer in kitchen/bath has fallen victim to this fate. If this happens in your speaker cabinet it will break the seal and cause an air leak. Les

 

You're talking out your ass. An aliphatic resin glue joint is stronger than the wood it joins. This is beyond common knowledge....hell, even Elmer's Glue-All, the white stuff, has been demonstrated in old TV ads as having greater-than-wood strength. The aliphatic resin bond, done properly uses tight joinery...the gap is intentionally very tight. Obviously this would be foreign to anyone accustomed to Bill's construction methods, but that's how anyone who's made it past high school woodshop was taught.

 

A dado joint is not intended to flex, it is intended to be as rigid as possible. These aren't wings on an airplane, they're speaker boxes. Stiffness is good.

 

And FWIW, a good cabinet drawer would be constructed with dovetails oriented so as to not slide apart with the force of closing the drawer. They dont' flex, and every drawer failure I've seen was either because the joints were poorly executed and too loose for a good glue joint, or the wood split or sheared.

 

This quote is from Franklin's FAQ. Note that they make both polyurethane and PVA adhesives (color added to emphasize):

 

How does Titebond

[tlbonehead]

I'd definitely make some Earthquake copies before I'd do those Tubas.

[tlbonehead]

You're talking out your ass. An aliphatic resin glue joint is stronger than the wood it joins. This is beyond common knowledge....hell, even Elmer's Glue-All, the white stuff, has been demonstrated in old TV ads as having greater-than-wood strength. The aliphatic resin bond, done properly uses tight joinery...the gap is intentionally very tight. Obviously this would be foreign to anyone accustomed to Bill's construction methods, but that's how anyone who's made it past high school woodshop was taught. A dado joint is not intended to flex, it is intended to be as rigid as possible. These aren't wings on an airplane, they're speaker boxes. Stiffness is good. And FWIW, a good cabinet drawer would be constructed with dovetails oriented so as to not slide apart with the force of closing the drawer. They dont' flex, and every drawer failure I've seen was either because the joints were poorly executed and too loose for a good glue joint, or the wood split or sheared.

I've seen tons of situations where a simple butt-joint secured with carpenter's glue(tite-bond, etc) stayed secure enough to break the plywood instead when trying to break it loose. That seems strong enough.

[atabner]

Just to re-iterate that the glue>wood strength is common knowledge - and i never made it past highschool woodshop!

[Craig Vecchione]

Quote: Originally Posted by Craigv Amazing how you think you know how many clubs and bars I've been in. How does one gain such clairvoyance, and does the condescention come with it as a package, or did you have to get that separately? No clairvoyance needed. I work for a soundco and run sound regularly, you do not. No condescention intended. As if it's actually necessary to explain this yet again, the great majority of bars and small clubs, venues appropriate to a Tuba-24, have no stage. The waitresses clear out a few tables, and the band sets up on the floor. It may be in a corner, or half-buried in an alcove used for private parties, or it may be along the middle of a wall. In any case, the subs are going under the mid-highs, as they are the means of elevating same, and the stack sure as hell isn't going behind the front line of mics in order to place it against a back wall, let alone against a back corner or both sides of the room. Even a proscenium style theater will often preclude optimal placement because the stage extends considerably from the proscenium and corner placement puts the mics in front of the stacks. Speaker stands work great here. Use speaker stands for the tops, place subs against the wall. Easy and simple and done quite often. Les

 

I do stand corrected on the clairvoyance issue, as it's obvious you know nothing about me.

 

So rather than use subs that perform just fine whilst sitting under and supporting my mid-highs, you think I should bring along added gear (in, as I've mentioned all along, an already too-small venue) in the form of speaker stands, and then need to deal with delaying the mid-highs to match my subs which are now back against a wall somewhere, all to get the Tuba to do what my SRX can do easily no matter where I place it. I don't think so.

[Craig Vecchione]

 

I've seen tons of situations where a simple butt-joint secured with carpenter's glue(tite-bond, etc) stayed secure enough to break the plywood instead when trying to break it loose. That seems strong enough.

 

 

Yet I'm supposed to believe, after decades of building wood cabinets, that a good tight dado or rabbet, secured with Titebond II, is in danger of falling apart.

 

I should instead join, for example an 80 degree angle using right-angle butts, so that the contact point is essentially a knife-edge (assuming any contact at all....remember, we don't need no stinking table saw, just a tape measure, circular saw, screw gun, and caulking gun). That reminds me: Les.....I'm still waiting to see pictures of the internal bracing holes you cut with that circular saw.

[Dan Magers]

I would think a spacer would be needed between the driver and its square circular saw cut hole.

 

Also, the mention of a loose brace making noise at hi power. Hmmm... must be a very small S/N.

 

Why do we always hear these "better than $3K box" claims yet, we never see 'em side by side?

[preacherman672]

 

Less working time and non-expandability are definate disadvantages in building speakers.

 

 

Les

[preacherman672]

 

I do stand corrected on the clairvoyance issue, as it's obvious you know nothing about me. So rather than use subs that perform just fine whilst sitting under and supporting my mid-highs, you think I should bring along added gear (in, as I've mentioned all along, an already too-small venue) in the form of speaker stands, and then need to deal with delaying the mid-highs to match my subs which are now back against a wall somewhere, all to get the Tuba to do what my SRX can do easily no matter where I place it. I don't think so. You are also packing a #250+ sub. I would gladly give a #150 to pack two speaker stands. Up to about 40ms of delay in non-directional frequencies is not noticeable by the average listener.

 

 

Les

[preacherman672]

Yet I'm supposed to believe, after decades of building wood cabinets, that a good tight dado or rabbet, secured with Titebond II, is in danger of falling apart. I should instead join, for example an 80 degree angle using right-angle butts, so that the contact point is essentially a knife-edge (assuming any contact at all....remember, we don't need no stinking table saw, just a tape measure, circular saw, screw gun, and caulking gun). That reminds me: Les.....I'm still waiting to see pictures of the internal bracing holes you cut with that circular saw. You don't have to cut the same amount of holes with the circular saw as you have to drill. In the 2" wide piece you talk about I would only have two holes. This is easily done with a circular saw. BTW a table saw and other tools aren't necessary, but they do make the job much easier.

 

 

Les

[DJ Swydez]

Wow this is a really intense and heated discussion! I find it very interesting! Carry on...

[preacherman672]

 

I would think a spacer would be needed between the driver and its square circular saw cut hole. Also, the mention of a loose brace making noise at hi power. Hmmm... must be a very small S/N. Why do we always hear these "better than $3K box" claims yet, we never see 'em side by side?

 

 

If you live close enough (I am on the I-20 corridor in the middle of North Louisiana) I would be willing to demo you a box sometime. I have a customer who purchased a pair of Tubas in College Station, maybe you could go to the club where they are and listen.

 

PM me for details if you are interested.

 

Les

[W. M. Hellinger]

Wow this is a really intense and heated discussion! I find it very interesting! Carry on...

I'm holding my tongue.

I will say that my decision to purchase a wood stove for my shop came slightly after my decision to attempt to build speaker cabinets. I'm still confident that I get more BTU's out of dry/split red fir than baltic birch plywood... regardless of how much glue is on the dadoed joints of that baltic birch plywood.

How many of my homemade speaker cabinets do I still own? Zero. Price of the learning experience? Mastercard knows quite well.

[agedhorse]

First of all, a proper drawer bottom is not rigidly bonded to the surrounding surfaces, it is designed to float in a dado to prevent torsion from swelling of the bottom in high humidity. That's why the edge joints are so important for overall strength.

Second, it seems like we are seeing more of the "blind faith" DIY cultishness again regarding this DIY product, this is exactly why I don't believe a lot of what I hear these days when they violate major engineering principles. I understand the enthusiasm for Bill's speakers and I think that's great. Nothing wrong with them until the claims become inflated to beyond reasonable IMO.

Third, the recommendation of 2x the RMS rating and then limiting the signal back to the RMS rating is EXACTLY the same as powering them at the RMS rating and is a waste of 50% of the available amplifier power. It is exactly the same as buying an amp 1/2 the rated power and setting the limiter at the same RMS value. In the thread (on Bill's site) I saw (quite a while ago), this concept was lost on everybody participating in the thread. Then the quesation of reliability really comes into play... how can so many speakers fail if powered so "conservatively"? Of course there were guys bridging big amps into little drivers and smoking them pretty quickly. Then wondering what happened!

Re. the defective speakers, I know enough about the failures to know that everyone should be very happy (overjoyed perhaps) with how Eminence handled your failures. IMO, they went way beyond what I would consider reasonable, but they are known for their excellent customer service and this is a great example.

A proper dado joint has a very thin glue line, and is structuraly designed to guarantee that the joint is always faced with primarily a sheer load, even in flexuror tension situations, which is why is is the strongest (non-dovetail or FJ) joint available.

You are arguing with people on this forum who have years of experience building all kinds of products. After 20-30 years of doing this thousands of times, and studying manufacturing methods, we get pretty good at it.

As far as not blaming the sound guy rather than the cabinet, that's why I DID include the possibility that the sound guy might have liked it like that, but I didn't see any eq on the sub band, and he was clipping/limiting the amp that he was using an it wasn't all that loud or deep sounding for a PLX-3002 (or maybe it was a 3402). Frankly, I wan not impressed or blown away. It was reasonable performance (from what I heard) for a box of that type, though it didn't sound like it went down very low or sound very round. Just my impression, which I think in the nature of fair play, should be included to balance out other people's opinions. Just because I didn't think it was super impressive doesn't mean that it's a bad speaker or not suitable for many applications. I also don't think it compares even remotely with tonight's VT4882's which are -3dB down into the low 30's and have an AVERAGE sensitivity in the 95-96 range. Granted it's a larger box and in the $3k+ range, but IMO a single one it KILLS the pair of TUBAs I heard. Not even in the same ballpark. And it was in the same venue, same positioning.