Need a nearfield design

[xyrium]

I've been considering Zaph's ZRT (2 way sealed version) or SR71 designs. Can one simply make a nearfield out of them by removing the BSC and placing the drivers as close together as possible, as well as the suggested midrange xover edits in the original design? I realize this sounds incredibly naive, but I had to take a shot at it.

If not, are there any suggested nearfield designs out there that can do F3 of 60Hz with low distortion? I will have about 2 ft to the front wall from the back of the speakers and about the same to the sides of each.

The only one I've located thus far is this one, but it's a work in progress.

http://www.htguide.com/forum/showthread.php4?t=31249&highlight=nearfield

Thanks!

[Cyan]

BSC may still be required if you don't place the speakers right in fron of the back wall. Infact jed did use a little of bsc for my speakers.
And he also adjusted the frequency response for my listening position (nearfield that is).
If your not on a budget, and space is not a problem, you may wanna try a sealed monitor with accuton 7'' (the sealed box version) in a 20l cabinet (or even more i think, for a lower Q), and a raal OEM.
So you'd have an even flatter frequency response (the raal is flatter than the fountek, and the accuton seems like to have less breack-up than the magnesium excel)

Btw, for very little extra price look what a crossover he made for my speakers (the avatar). Most manufacturers use a pcb and cheaper components for that price.

[xyrium]

Thanks Cyan! I suppose I need to qualify the project with a cost though. I think the ZRT is at the top of my price range (about $1300.00 USD with cabs). So, I think the Accutons might be precluded from consideration.

The music is Pop, Rock, and a little Jazz Fusion and Blue. So, they have to be dynamic, though not as dynamic as the requirements for Classical.

My seated position will be about 5 ft away. They are primarily being used as studio monitors. So, I need them to sum pretty quickly.

Thanks!

[Cyan]

Yeah that's a tight budget. So, a solution could be to use the ones i indicated before (the seas + fountek), and maybe in the future add a sub.
Or else you'll have to try a design with more conventional drivers.

[xyrium]

In reality, I'm usually happy with something that can produce clean SPLs at 60Hz (my old Dyn Audience 52s). That's why I'm so interested in the SR71. From the graph, and the woofer measurements, it does just this. The only problem is the nearfield situation.

If I build the ZRTs, again the nearfield problem exists, but also there is no recommended ported, yet also bookshelf design. Therefore, I'm stuck with the sealed design, and it only appears to hit F3@70Hz. I suppose there are Excel designs out there doing something similar, I need to look around.

Getting the kits at a 10% discount from Madisound is a nice incentive, though I'm ok with assembling the xover myself. Also, building the SR71 gives me a bit more funds to use towards an amp. I'm currently planning on using a B&K 200.2, but may scale back to the 125.2 if I go with the ZRT.

[JonW]

xyrium-

I just typed out a long reply on your project needs in the other thread on my mini MT project (post # 94). Good luck with it.

http://www.htguide.com/forum/showthread.php4?t=31249&page=3

[Undefinition]

If I had to buy/build another nearfield monitor for mixing, I'd do a pair of Jeff Bagby's LS3/5a "clones." He used the RS28a + Aurum Cantus AC130 (I think). It's an absolutely phenomenal speaker, for nearfield or otherwise. I don't think he has officially put the project out there, however if you ask him nicely, he may divulge the plans. (He hangs out on the Parts Express board, by the way)

[Operandi]

I think there are lots of options that would probably work well. I am certainly no expert but aside from BSC I don't really think there are many nearfield considerations to take into account. Perhaps the response on axis might be more of a priority?

I'm actually in a similar position; I want a reference level (within my budget) system on my desktop. I think I've narrowed it down to two RS150 speakers Jeff Bagby's Dreydels and Scott S.'s RS150 - Neo3 design. Scott and Jeffy both said their designs would function well nearfield without modification. I however will be using stands, if you plan to place them on a desk surface you may have to take some BSC into account.

The RS150 is a bit smaller than the drivers you are looking at but in the right enclosure 60HZ is not a problem.

[Cyan]

Another solution that came to my mind is the ellis. Though if you want them sealed (and you have for your position, as the vented has a rear reflex), you'll have to buy them from jim salk, and i think they cost more than 1300 dollars.
Or you could ask jed and see how much he takes to build the ellis sealed (most likely less than salk).

[Jed]

Or you could ask jed and see how much he takes to build the ellis sealed (most likely less than salk).

I wouldn't replicate Dave Ellis' design because he's a great guy and it's his speaker idea. I could design something else though.

[JonW]

xyrium-

As I've thought about your needs for a near field design more... and to add to what I wrote in the other thread...

I have seen various small speaker designs out there with no BSC such that they can be used up against a wall. I can't think of any, in particular, at the moment. But I think that Zaph has some no BSC crossover options for some of his speakers. Take a look at the designs over at zaphaudio.com. You'll likely find something. As well as the other options out in the ether than I cannot think of, specifically, at the moment. If you are after really low distortion above all else, then see my comments in the other thread. Good luck.

[xyrium]

xyrium-

I just typed out a long reply on your project needs in the other thread on my mini MT project (post # 94). Good luck with it.

http://www.htguide.com/forum/showthr...t=31249&page=3

Hi Jon,

I'm totally envious of your work. Very nice attention to detail. Thanks for the post, I didn't want to hijack your thread, so i ws redirecting to this one.

This said, I don't need or even particularly want a sealed design. If I could avoid using a sub, I would prefer such. This is because I have some nasty room modes mucking up the sound at 65Hz, and 70Hz or so. I've tried integrating a sub by plugging up the ports on my old Emu PM5 monitors, down to a sealed 10" unit, and it was very difficult (I abandoned efforts altogether). Therefore, I'm very happy to build a small TM that can do 60Hz with authority. I truly don't need the lower octaves (40Hz and below) for what I listen to (Rock, Blues, Jazz, and Pop).

I remember reading about the Spassvogels, I need to check those out again (Edit, just realized they are floor standing, so those are out). The RBR sounded like a great design as well, though it's no longer available. I do prefer to use Euro or USA made drivers however, personal reasons I suppose, so no offense to China made stuff like the very well respected Dayton reference units or those using them to a great effect. So, obviously that increses the price range. However, I still figured that for a kit, $1300 should get me a good bookshelf design (including the ZRTs, Spassvogels, ZD5s, etc). I suppose I just need to determine how to implement them in a nearfield situation. Therein lies the tremendous interest in your current project! So, finish it up will ya!

Rgds,
Paul

[xyrium]

Thanks Operandi. I noticed a few mentions of attentuating the midrange a bit for nearfield placement in one of Zaph's articles. Additionally, maybe reduced BSC isn't as important since the units will have some breathing room (2ft side and back).

I'm totally disppointed in the discontinuation of the RBR. Seemed perfect. Heck, I could have factored in the cost of a sub for the low cost of that design, just for fun. I'd probably low pass it at 40, 2nd order... Make me sad thinking about it. :\ However, the sealed MD20 cab version of the ZRT may get me what I need though from a low distortion, low frequency persepctive.

I think there are lots of options that would probably work well. I am certainly no expert but aside from BSC I don't really think there are many nearfield considerations to take into account. Perhaps the response on axis might be more of a priority?

I'm actually in a similar position; I want a reference level (within my budget) system on my desktop. I think I've narrowed it down to two RS150 speakers Jeff Bagby's Dreydels and Scott S.'s RS150 - Neo3 design. Scott and Jeffy both said their designs would function well nearfield without modification. I however will be using stands, if you plan to place them on a desk surface you may have to take some BSC into account.

The RS150 is a bit smaller than the drivers you are looking at but in the right enclosure 60HZ is not a problem.

[Jed]

I'm totally disppointed in the discontinuation of the RBR. Seemed perfect. Heck, I could have factored in the cost of a sub for the low cost of that design, just for fun.

I revised the design with the better sounding Scan Speak HDS tweeter in the new format called the "C5."

[JonW]

Hi Jon,

I'm totally envious of your work. Very nice attention to detail. Thanks for the post, I didn't want to hijack your thread, so i ws redirecting to this one.

Hi Paul,

Thanks for the kind words. Yup, good idea to keep the discussion here in this thread.

This said, I don't need or even particularly want a sealed design. If I could avoid using a sub, I would prefer such. This is because I have some nasty room modes mucking up the sound at 65Hz, and 70Hz or so. I've tried integrating a sub by plugging up the ports on my old Emu PM5 monitors, down to a sealed 10" unit, and it was very difficult (I abandoned efforts altogether). Therefore, I'm very happy to build a small TM that can do 60Hz with authority. I truly don't need the lower octaves (40Hz and below) for what I listen to (Rock, Blues, Jazz, and Pop).

Getting more bass is difficult. Designing in less is really easy. For the ported designs we’ve discussed (ZRT, Spassvogel, etc.) you can usually just move the port to the front. Or skip the port and go sealed. Changing the bass tuning is typically pretty easy and does not require any crossover redesign. Just pick your bass goals and make the volume accordingly. Be sure to keep the front baffle around the drivers the same as the original design.

I remember reading about the Spassvogels, I need to check those out again (Edit, just realized they are floor standing, so those are out).

You don’t need to make them floorstanders. All the volume of the cabinet was not used. (One of the shelf braces sealed off the rest of the volume.) Just keep the top ~17-20” of the cabinet with the facets there. Then modify the volume to your bass goals, via how deep you make the cabinets. I would think that you could also shrink the ZRT cabinets in a similar manner if you are OK to give up the bass (which is seems like you are). Or many other larger speakers. Zaph’s ZD5 is another low distortion design which is already in a small box (but not designed for being up against a wall, if I recall correctly).

The RBR sounded like a great design as well, though it's no longer available. I do prefer to use Euro or USA made drivers however, personal reasons I suppose, so no offense to China made stuff like the very well respected Dayton reference units or those using them to a great effect. So, obviously that increses the price range. However, I still figured that for a kit, $1300 should get me a good bookshelf design (including the ZRTs, Spassvogels, ZD5s, etc). I suppose I just need to determine how to implement them in a nearfield situation.

Yeah, the RBR looked like a very good deal. Oh well. I guess we can’t complain if the RBR- and the actual economic recession- seem to be going away. (Assuming everyone can get back their jobs)

For your needs I’d recommend a 2 way MT design of some sort. And for MT’s I’d say, though, that $1300 will not get something “good.” You’ll get pretty much as good as a well designed speaker can possibly be. You can hardly spend more than that on an MT unless you try really hard.

Therein lies the tremendous interest in your current project! So, finish it up will ya!

I’m working on it! I’m working on it!