Future (active?) recommendations please, for a noob

[jinjuku]

What are recommended local resources for finding the right parts for the xover, assuming that PE or any other online retailer doesn't have them? Though the stated 10% allowable variance on values does seem to be very forgiving, I'll still try to aim for dead center.

Does anyone have major objections to exclusively using Neutrik connections on the speakers?

Unless you live near a large city you may be SOL on getting caps/l's/Inductors/Resistors in values that you need.

I use Erseuadio for my x-over builds. Then there is Parts Express and Madisound also.

Neutrik all the way. You only need the NL2's.

 

[Swerd]

What are recommended local resources for finding the right parts for the xover, assuming that PE or any other online retailer doesn't have them?

The crossover parts list does include the Parts Express or Madisound part numbers for each part. Send me your email address by PM, and I email you a Word document containing all the details.

I'd like to ask what the proper adhesive would be to mount these parts, but I'm pretty sure Alden's book might tell me, which I have just now ordered as that was recommended by Swerd in yet a different thread. That should really help limit the number of unnecessary and stupid questions I might ask.

I attach the crossover parts to a thin board (¼" thick pegboard) with nylon cable ties. Then I use a few screws to attach the board to the cabinet interior. No glue, no mess.

Alden's book deals with acoustic and electrical design, but not construction details because there are many different ways to build things depending on the tools and skills you have.

… regarding the ER18s, I'd like to know if the front baffles are absolutely necessary, or very highly recommended for a performance reason or other. I am also curious as to the reason for the horiz tweeter offset, perhaps it has to do with lobing/interference angles.

The front baffles, as I originally showed them, were an attempt to copy the appearance of Salk speakers. If you want the front of the cabinet to extent full length, that should not be a problem. Just omit that extra front baffle piece.

The horizontal offset of the tweeter does have an acoustic purpose. Keep it that way. Short wavelength sound from tweeters can diffract off the cabinet edges, creating new sound origin points on each cabinet edge. If the tweeter is centered, these new sounds can reinforce or cancel the sound from the tweeter itself, causing uneven sound. Off setting the tweeter, making each edge a different distance from the tweeter helps to minimize this problem. I chose the offset distance so the edge-to-tweeter distances have a ratio that is a factor of the square root of 2 (an irrational number for those who remember high school math). That way the diffracted sounds make the smallest impact overall. The rounded cabinet edges also contribute to this. These are both relatively small matters, but if you're making the cabinet, why not do it right. The tweeter offset is easy, the rounded edges require a router and a ¾" radius roundover bit.

Does anyone have major objections to exclusively using Neutrik connections on the speakers?

For the speaker wire terminals? No problem. Use whatever terminals float your boat.

 

[jinjuku]

The crossover parts list does include the Parts Express or Madisound part numbers for each part. Send me your email address by PM, and I email you a Word document containing all the details.
I attach the crossover parts to a thin board (¼" thick pegboard) with nylon cable ties. Then I use a few screws to attach the board to the cabinet interior. No glue, no mess.

You mean like this

 

[Swerd]

I know I'll sound even more insane, but I really do want to try height speakers sometimes. So far as I know, they do not need to be very capable speakers, but I do think it would be best to voice match them. Would the below be good candidates? (For bookshelves, there are probably few to none that are "similarly voiced" to the ER18s?) I admit I wouldn't mind spending less or reducing the amount of work (but I am definitely not crossing my fingers on that one). Thanks. Oh, side question regarding height speakers: what kind of bracket/mount would anyone recommend to install on the speaker itself?

http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm

Not sure what you mean by "height speakers". Do you mean smaller cabinets, such as bookshelf types, mounted up high?

The Mark K ER18DXT 2-way design you linked looks very good. I hadn't seen that before. Another similar design with a slightly different SEAS dome tweet is the Zaph Audio SR71 kit. It's available both as a complete kit, or parts alone from Madisound.

Both designers have very good reputations, and they and the Murphy MTM all share the same excellent woofers, but I couldn't tell you for certain just how similar they all sound. I suspect both of those 2-ways will be a pretty good match with the ER18 MTM.

GranteedEV's point about voice matching is a good one:

Voice matching does not require the same drivers. A pair of MBOW1s or CAOW1s would probably "voice match" the ER18s in the sense of timbre as they were designed with the design same goals.

The woofers in both of those 2-way designs by Dennis Murphy are 5½" and cost less than the ER18 woofer. Because the crossovers were designed to sound similar, they would make excellent center or rear channel speakers along with the ER18 MTMs in a HT system. They won't produce bass like the floorstanding MTMs, but for a center channel dialog only speaker, they would be excellent. I built a pair of the CAOW1s about 5 years ago and love them. They are in my bedroom as a two channel system. They sound very close (other than bass) to my SongTowers.

 

[Swerd]

I want to build Dennis Murphy's Usher 2-way.

I'm curious why you want to build that one. Dennis once told me he was disappointed with that design and preferred the CAOW1 instead. I didn't ask any further questions about why he felt that way.

If you want it because the woofer is 7", it may be time to talk Dennis into designing a 2-way with the SEAS ER18 and the Dayton RS28F tweeter . I know he likes that woofer much better than the Usher, which I believe is not available anymore. And he already used that tweeter in the dome tweeter version of the ER18 MTM.

 

[GranteedEV]

I'm curious why you want to build that one. Dennis once told me he was disappointed with that design and preferred the CAOW1 instead. I didn't ask any further questions about why he felt that way.

If you want it because the woofer is 7", it may be time to talk Dennis into designing a 2-way with the SEAS ER18 and the Dayton RS28F tweeter . I know he likes that woofer much better than the Usher, which I believe is not available anymore. And he already used that tweeter in the dome tweeter version of the ER18 MTM.

My guess for his dissapointment with the ushers was that there wasn't much consistency between drivers. That's never a good thing but in this case i have this gut feeling that usher 9950 is a tweeter I really want to hear in a well done speaker. The usher woofer is of little interest to me. I have no doubt the seas pulp cone woofer is much better. I think what I would probably do if i were designing it myself would be to take an Exodus Anarchy with the Scanspeak 9500, cross them fourth order around ~1.6 to ~2.2khz (wherever would be optimal) and work outwards from there, notch filtering etc. It's nothing like a dennis murphy design. But that's exactly why i would want to build his usher 2-way... as a comparision.

edit Wait not the scanspeak i meant the usher 9950

If i did do this, the dennis murphy would be passive and my build would be done with a miniDSP and a pair of miniAMPs.

 

[Swerd]

My guess for his dissapointment with the ushers was that there wasn't much consistency between drivers. That's never a good thing but in this case i have this gut feeling that the sca...usher 9950 is a tweeter I really want to hear in a well done speaker. The usher woofer is of little interest to me. I have no doubt the seas pulp cone woofer is much better. I think what I would probably do if i were designing it myself would be to take an Exodus Anarchy with the Scanspeak 9500, cross them fourth order around ~1.6 to ~2.2khz (wherever would be optimal) and work outwards from there.

edit Wait not the scanspeak i meant the usher 9950

Interesting. Dennis never said anything bad about the Scanspeak 9950 or Usher 9950, other than the SS costs too much. Still, he never chooses to use it in a design.

His favorite dome tweeters are the various ¾" Hiquphon models which are quite similar. They can be crossed as low as 2500 Hz, and I don't think that would work with the ER18. That's why he used the RS28F, which he claims is built by Usher for Parts Express and seems to be quite similar to the Usher 9950, at a lower cost.

For higher priced tweeters, he clearly prefers ribbons such as the Aurum Cantus G2, the LCY 110 (has had QC and supply problems lately), and the RAAL, over any dome. And for lower cost ribbons, he now likes that Fountek model in the ER18 MTM. It was a challenge to get it to work in a 2-way crossed at 2200 Hz (I believe). He tried using the BG Neo 3 planar in the same design, but never got it to work.

 

[jinjuku]

Interesting.
For higher priced tweeters, he clearly prefers ribbons such as the Aurum Cantus G2, the LCY 110 (has had QC and supply problems lately), and the RAAL, over any dome. And for lower cost ribbons, he now likes that Fountek model in the ER18 MTM. It was a challenge to get it to work in a 2-way crossed at 2200 Hz (I believe). He tried using the BG Neo 3 planar in the same design, but never got it to work.

I would love to hear a converstation between Dennis Murhpy and John Krutke about ribbons:

Zaphs take:

None of the three true ribbons have very distinguished performance. They are more similar than different. But if I had to choose one, it would probably be the Fountek NeoCD2.0 because of it's durable ribbon, smooth response and clean top end performance. I'm not sure if I could live with that vertical off axis response, as I occasionally don't like to be locked in to sitting ear height. Generally, these ribbons do not live up to their price and hype. This point is driven home by their comparison to the cheap little Vifa neo dome.

 

[Swerd]

I would love to hear a converstation between Dennis Murhpy and John Krutke about ribbons:

Zaphs take:

None of the three true ribbons have very distinguished performance. They are more similar than different. But if I had to choose one, it would probably be the Fountek NeoCD2.0 because of it's durable ribbon, smooth response and clean top end performance. I'm not sure if I could live with that vertical off axis response, as I occasionally don't like to be locked in to sitting ear height. Generally, these ribbons do not live up to their price and hype. This point is driven home by their comparison to the cheap little Vifa neo dome.

They might just politely ignore each other .

Zaph always chooses low distortion drivers. Dennis agrees with his judgments on most woofers, as the ER18 has very low distortion, but he likes tweeters, ribbons and the Hiquphon domes, that have higher distortion in Zaph's measurements.

In my more limited experience, most of the distortion coming from tweeters originates from tones in their lower frequency range. If you choose your tweeter high-pass filter point and roll-off curve carefully, you can avoid exposing the tweeter to tones that generate the worst harmonic distortion. I don't remember exactly how Zaph does his distortion measurements, but he may do them with only a minimal single capacitor. So depending how you implement the crossover, you can use a tweeter with a higher potential for distortion, in a way that actually produces much lower distortion levels.

This is probably an oversimplification of a complex problem.

 

[lsiberian]

My experience:
BB costs 3 dollars more a 2' x 4' sheet. BB warps more though and burns more. Finishing is pretty even work on both IMO, but painting edges is work with either wood. That being said I build everything out of plywood. If you ask woodworkers in the AH equivalent what to build things out of they nearly always say PLY over MDF.

On seams:
Hiding seams isn't necessary in some cases(I'm too lazy to do it), but if you want to there are several methods for doing this. Curved plywood from tapease is what Chris and Andrew both use and Quarter round is what Mark uses. I just roundover the edges and paint enamel over the plywood.

To me building the crossover is more complicated, but I'm probably just selling myself short. I'd prefer to do passive crossovers for my 3-ways, but I'm not comfortable enough with passive crossovers. To attempt it.

 

[jostenmeat]

Wow, thanks guys for the excellent discussion. jinjuku, thanks for the input regarding xover parts. Yes, all I need is NL2s if building the ER18s, but if I happen to go active . . . And what the heck is up with that xover board?!? lol

All, it looks like I must cross off any ribbon tweeter, after the recent discussion. Vertical response is absolutely key in my HT, as I have two rows.

I am sure these must be truly fantastic speakers, and for the money, perhaps ridiculously fantastic. However, I do wonder just a teeny weeny bit about how great the advantage of TL design is in the grand scheme of things; if only that I do not get to learn about a different design that may be superior in terms of dialogue, offaxis response, perhaps efficiency, and perhaps the ability to select superior drivers to even what the ER18 uses. Surely I'd be giving up bass SQ and capability, but I do wonder just that tiny bit. After all, I know at least a few AHers are pretty biased on this technology (and I'm sure for good reason).

Swerd, thanks a lot for your assistance. I will use the square root of 2, for width ratios. I will have to choose a side for my center speaker though. Maybe I'll start a poll. j/k.

Oh almost forgot, the height speakers are like presence speakers. I know there are some AHers that use em, lemme see if I can find a pic. I would likely be using Audyssey DSX to provide these channels. I'm not dead set on it, but if I have the space and capability, it would be fun to try. Ok, here is an outdated pic: http://forums.audioholics.com/forums/showpost.php?p=657481&postcount=626


Does anyone know what people use for brackets/keyholes to mount directly on a bookshelf speaker? I don't even know if there are certain standards for keyhole widths, etc.

Also, I'm thinking of setting up a temporary shop. Ideally, what are all of the tools that I could ideally obtain, and specific model recs are welcome. I understand that I should pick up a bevy of good clamps. I assume Titebond will be fine for glue. I'm thinking of doing basic rips at my friend's shop with a table saw, then I can do some "finer" work, if need be, at home. Is a roundover bit all I need after the first rips? I'm a DIY noob, but I have been trying to embrace DIY for the first time this year, and I am really enjoying it. A lot.

 

[jinjuku]

Wow, thanks guys for the excellent discussion. jinjuku, thanks for the input regarding xover parts. Yes, all I need is NL2s if building the ER18s, but if I happen to go active . . . And what the heck is up with that xover board?!? lol

All, it looks like I must cross off any ribbon tweeter, after the recent discussion. Vertical response is absolutely key in my HT, as I have two rows.

I am sure these must be truly fantastic speakers, and for the money, perhaps ridiculously fantastic. However, I do wonder just a teeny weeny bit about how great the advantage of TL design is in the grand scheme of things; if only that I do not get to learn about a different design that may be superior in terms of dialogue, offaxis response, perhaps efficiency, and perhaps the ability to select superior drivers to even what the ER18 uses. Surely I'd be giving up bass SQ and capability, but I do wonder just that tiny bit. After all, I know at least a few AHers are pretty biased on this technology (and I'm sure for good reason).

Swerd, thanks a lot for your assistance. I will use the square root of 2, for width ratios. I will have to choose a side for my center speaker though. Maybe I'll start a poll. j/k.

Oh almost forgot, the height speakers are like presence speakers. I know there are some AHers that use em, lemme see if I can find a pic. I would likely be using Audyssey DSX to provide these channels. I'm not dead set on it, but if I have the space and capability, it would be fun to try. Ok, here is an outdated pic: http://forums.audioholics.com/forums/showpost.php?p=657481&postcount=626


Does anyone know what people use for brackets/keyholes to mount directly on a bookshelf speaker? I don't even know if there are certain standards for keyhole widths, etc.

Also, I'm thinking of setting up a temporary shop. Ideally, what are all of the tools that I could ideally obtain, and specific model recs are welcome. I understand that I should pick up a bevy of good clamps. I assume Titebond will be fine for glue. I'm thinking of doing basic rips at my friend's shop with a table saw, then I can do some "finer" work, if need be, at home. Is a roundover bit all I need after the first rips? I'm a DIY noob, but I have been trying to embrace DIY for the first time this year, and I am really enjoying it. A lot.

1> Look HARD at the Zaph ZA5.5 (WTWWW or WWTWW) his ZA5 driver simply blew me away.

2> On the tool side: You MUST build a cross cut sled
a> One 90 degree sled
b> One 45 degree sled
You will get $1000 cuts on a $300 table saw. Safer, quicker, and more accurate cuts.

3> Pick up two routers (craigslist is your friend) one for the round over / flush bit and one for the straight cut bit with a circle jig (either Jasper or Craftsmen.)

Router bits you will want:
1. 1/4 inch straight up-cut bit
2. Rabbet bit width variable with bearrings (think speaker flush mounting)
3. 3/4 inch round over bit
4. 1/4 or 1/2 45 degree bit (back baffle driver hole chamfer)

Use t-nut (huricane nut) with a 90 degree jig for the drill. Think poor mans drill press (Craftsman ~$20).

 

[lsiberian]

I've never used a table saw to build speakers. I wouldn't recommend shelling out the cash unless you plan to use it for building other stuff.
I use a good circular saw with a self-clamping straight edge and a Forrest Blade. http://www.amazon.com/Forrest-WW07Q607100-Woodworker-32-Inch-Circular/dp/B000OMQGBQ/ref=pd_cp_hi_1 Forrest blades cut through wood like butter and make sanding unnecessary because they leave a smooth finish on the wood. If you have money to spend you can always get their plywood blade, but the blade I linked will do the job well.

For a router I use the plunge base Bosch 1617(see CPO-Bosch on ebay) I never use my fixed base for anything. You can get both bases though just to be safe, but I just thought you should know the fixed based isn't always useful for speaker projects which require greater depth than it goes. I use 1/4" spiral upcut bit and a jasper jig for holes and recesses and a flush trim bit to clean up edges. The best bit I own is a holbren made by whiteside. See holbren.com for all your future bits and you will have great success.

For glue up get corner clamps to make setup a cinch. Get 4 of them . For bar clamps I prefer the Home Depot clamps to the Lowe's ones because the indent hurts my hand after a while.

You will need a drill. Plug in ones are very low cost and last forever if you are a cheapskate. Nearly all of them come from the same factory in china.

There are a lot of little details that will be better once you get started. Feel free to ask me if you have any further questions. Be sure to practice proper safety protocols.

 

[Swerd]

It seems that people have different tools, and that determines how people build their woodwork projects. Table saws are a good example. I don't have one, and neither does lsiberian. Others, swear by their table saws and claim it is the most important tool they have. So who is right? Both.

I get by because Lowes and Home Depot have large panel saws in the store where they can make the initial cuts from a sheet of wood I buy. Uncut sheets are 4x8 feet, and I need them cut before I can take them home. Sometimes, depending on who cuts it for you, the dimensions may not be precise. If I need a 12"x44" piece, I ask them to cut it about and inch wider and an inch longer. When I get home I can trim it to exactly what I need. I use a hand-held circle saw and a clamped on strait edge to do that.

Other tools I use:

Circle Saw - with standard 7" blade

Plunge router - DeWalt 621
Some routers come with two bases, plunge & fixed. Buy a router that has a 1/2" diameter collet to hold the bits and avoid one that only has a 1/4" collet. I mentioned the DeWalt 621 because it has a way to direct dust and chips directly into a shop vacuum. MDF makes a prodigious amount of dust, and collecting as much as you can as you make the cut is a very good idea.

Jasper circle
Gives excellent result when cutting flush mount speaker holes. You can also make your own jigs, but for a newbie the small Jasper jig will be a favorite.

Router bits
1/4" spiral upcut bit for speaker holes. Also an assortment of straight bits from Freud, Whiteside, or other good makers. A 1/2" straight bit is the one I most often use.
Trim bits - that have a bearing
Round over bits - Warning - these require using a table mounted router. Do not try using a 3/4" round over bit on a hand held router!

Clamps, clamps, and more clamps. For glue up. I avoid using screws.

If you've never done woodwork, a beginner's course is a good idea. I learned lots about making jigs from scrap wood. Its easy and essental to doing good work.

There are many other smaller tools, but I can't think of them now.

 

[jinjuku]

Table saw + 45 degree cross cut sled = perfectly mitered corners with zero tear out since the cut is zero clearance. That means less finish work.

Another thing that a table saw makes easy is dado's. I dado the internal window brace and the back panel (about a 1/2" overhang on the back). Cabinets are atypically strong and the 1/2" lip on the back gives something for corner clamps to hang on to . The dado's give me more surface area to glue, help insure alignment and make assmembly easier.

My major tool purchases have all been on Craigslist. If you don't have a table saw then build a track saw at least. YMMV. I picked my Jet contractors saw for $350 delivered to my door from Clist.

 

[jostenmeat]

Quick question: Rounding over the edges is purely for aesthetics, or is there a performance reason, maybe something to do with diffraction? I assume it's for looks only, but I don't want to ASSume any more than I can help it with this kind of project.

Thanks a lot guys for the experience and advice. So I picked my friend's brain (the guy that helped me cut the wood for my new screen frame and false wall). He wants to help me do this project too! However, he is awfully busy right now, essentially does not have a single day off for months at this point, so I dunno. I did take an extremely basic class as a young kid, making a tool box, cutting board for mom, etc. The latest project was definitely a crash course, and I was using a chop saw at 90/45, table saw, planer, etc, doing rabbets, dados, etc.

However, the dados were very thin, just requiring a couple of passes with table saw. My friend has something against dado blades/bits. So I asked what does he do with a wider dado. He uses a router with the right bit. He'll set up a jig or fence or whatever, and if the excess wood is going to be cut off, he'll just drill right into it for security, otherwise clamps. He would set the jig on the side that the router wants to naturally move to.

His table saw is a very nice pro/shop saw, but he did mention that his first was a contractor's.

I know he thinks Panasonic makes the best impact drills, but he said that DeWalt just came out with some combo kit, and that he particularly loves how small they are. He has to have it, and will get it. He even told me how many there are in the surrounding area, two at one store, and three at another.

For clamps, he says instead of getting expensive stuff like he has, he recommends buying some clamp kits or something, to make "pipe clamps". I'll google later.

Oh btw, I have been convinced to use MDF after all for speakers. I will buy the good stuff from the high end store where I recently bought my Phillipine Mahogany, and not at Home Depot.


Well for now, I will at least* get the following items:

Sawhorses and 1" MDF for my makeshift table.
Bunch of clamps of one kind or another.
Decent router, assortment of bits and jigs.

I wouldn't mind owning a table saw, I just don't really have the space for it. I am also not sure if I need a circle saw, assuming I have resources to go to with decent table saws. We will see. Maybe I can trust myself to make perfectly straight cuts.

 

[jinjuku]

Quick question: Rounding over the edges is purely for aesthetics, or is there a performance reason, maybe something to do with diffraction? I assume it's for looks only, but I don't want to ASSume any more than I can help it with this kind of project.

The rounding over of the baffle helps with diffraction loss. So it is more than cosmetic.

His table saw is a very nice pro/shop saw, but he did mention that his first was a contractor's.

You could get a killer router table. It would take up less space. Somethings would be easier, some harder than a table saw. And you could do some things on a router table that you can't do on a table saw (think rail and stile etc...).

For clamps, he says instead of getting expensive stuff like he has, he recommends buying some clamp kits or something, to make "pipe clamps". I'll google later.

For clamps? Two words: Harbor Freight.

 

[jostenmeat]

The rounding over of the baffle helps with diffraction loss. So it is more than cosmetic.

Ah, thanks!

You could get a killer router table. It would take up less space. Somethings would be easier, some harder than a table saw. And you could do some things on a router table that you can't do on a table saw (think rail and stile etc...).

Thanks for the suggestion!

For clamps? Two words: Harbor Freight.

okie dokie. I figured to still look into my friend's idea, because I don't want the outlay for tools to be too big at the beginning. I suppose I can add more over time. Thank you, jinjuku.

 

[lsiberian]

The rounding over of the baffle helps with diffraction loss. So it is more than cosmetic.

If you want maximum benefit of roundover 4" curved plywood is it. You can build a Wmax level speaker that way. I might do this soon.

 

[Swerd]

Quick question: Rounding over the edges is purely for aesthetics, or is there a performance reason, maybe something to do with diffraction? I assume it's for looks only, but I don't want to ASSume any more than I can help it with this kind of project.

The rounding over of the baffle helps with diffraction loss. So it is more than cosmetic.

Rounding over the cabinet edge helps smooth out small peaks and dips in the frequency response in the mid to upper treble range. Read this small entry by Dennis Murphy. It describes how a 3/4" round over on the cabinet edges of a small 2-way speaker helps smooth out a small peak at about 4 kHz and a small dip at about 7 kHz. The differences are clearly visible in his frequency response curves made from speakers in cabinets with and without the roundovers. The question is, of course, is this difference audible? That's harder to say. Dennis has the opinion that if a speaker's frequency response can be made measureably smoother without great expense, like using rounded cabinet edges, then why not do it. It seems that a 3/4" radius round over is good enough.

I included the quote from jinjuku because of a small point. (Call me picky if you want.) He is basically correct, except that the term diffraction loss is often used to mean something different than the kind of treble diffraction effects Dennis Murphy shows in his graphs. Diffraction loss, also known as baffle step response, comes at lower frequencies, roughly 500-1500 Hz when using fairly narrow cabinets. Frequencies below that range are 3-6 dB quieter than above that range. This is easily audible. It is corrected not by changing the cabinet edges, but by an equalization circuit in the crossover, called baffle step or diffraction loss compensation.

A more detailed explanation of what diffraction loss, or baffle step response, is and how to correct it is here.