or Connect
AVS › AVS Forum › Audio › DIY Speakers and Subs › Hey guys...we need a little rallying here...
New Posts  All Forums:Forum Nav:

Hey guys...we need a little rallying here... - Page 205

post #6121 of 9844
Quote:
Originally Posted by Erich H View Post

They're all very good for the price range you're hoping to stay in......or they wouldn't be listed. There are 2-3 designs that were worked on, but not listed. One was a smaller model, one was with a 10" B&C. They didn't bring enough to the table to justify the price, so they weren't done.

Just wanted to quote for truth.

There have been a number of designs discussed between Erich and I, where I've said flat out to him, don't flat pack it.
post #6122 of 9844
Eric H & Co,

In terms of sheer high-fidelity sound quality, how does the SEOS 12 or 15 with a really good compression driver compare against the Beyma TPL-150H?
Edited by NiToNi - 12/10/12 at 12:29pm
post #6123 of 9844
What shipping method are you using? I'd feel pretty guilty ordering from Alaska if the shipping was stupidly high. Fedex tends to be the biggest offender. A lot of subwoofer companies like to only ship using fedex and it usually ends up being $100+ for the cheapest fedex method.
post #6124 of 9844
I beleive Erich uses UPS, pretty sure the overnight sensation flatpack came that way when i got it this summer
post #6125 of 9844
It's actually Fed Ex. But shipping to Alaska or Hawaii couldn't be included in the free shipping because the rates are very high. It would have to go by USPS or it would likely cost hundreds of dollars. I'm figuring about $30 on each heavy kit right now.
post #6126 of 9844
Jeff, you mentioned there was response shaping of diffraction... what would you say was the cause of this? I was under the impression that the big waveguide would reduce much of the diffraction effects, at least horizontally.
post #6127 of 9844
Quote:
Originally Posted by NiToNi View Post

Eric H & Co,
In terms of sheer high-fidelity sound quality, how does the SEOS 12 or 15 with a really good compression driver compare against the Beyma TPL-150H?

I don't know anyone who has made the comparison. Mind you the TPL-150H will beam vertically pretty highly at higher frequencies, so standing up will change the tonal balance. SEOS will shape the beam in the HF too, but maybe not to the same extent (I've not compared the directivity index).
post #6128 of 9844
Quote:
Originally Posted by Eternal Velocity View Post

Jeff, you mentioned there was response shaping of diffraction... what would you say was the cause of this? I was under the impression that the big waveguide would reduce much of the diffraction effects, at least horizontally.

I got the impression he was talking about baffle step compensation, and he corrected for a little bit of diffraction at the top of the baffle step region from the woofer.
post #6129 of 9844
Quote:
Originally Posted by Erich H View Post

It's actually Fed Ex. But shipping to Alaska or Hawaii couldn't be included in the free shipping because the rates are very high. It would have to go by USPS or it would likely cost hundreds of dollars. I'm figuring about $30 on each heavy kit right now.
Nice, thanks for considering us poor states that might as well be on mars according to Fed Ex. Pretty much any website that says free shipping (besides Amazon) excludes Alaska and Hawaii.
post #6130 of 9844
I might've missed this in the thread, is there any auto cad drawings/dimensions for building the flat packs DIY? I'm mostly interested in the bracket cut outs, since they are pretty different than a straight cut. Kinda anxious, wanting to get a head start on building and painting the speakers.
post #6131 of 9844
Quote:
Originally Posted by Eternal Velocity View Post

Jeff, you mentioned there was response shaping of diffraction... what would you say was the cause of this? I was under the impression that the big waveguide would reduce much of the diffraction effects, at least horizontally.

Not for the tweeter, for the woofer. The cause is the cabinet. There is a diffraction peak that must be leveled out.
post #6132 of 9844
Quote:
Originally Posted by tuxedocivic View Post

I got the impression he was talking about baffle step compensation, and he corrected for a little bit of diffraction at the top of the baffle step region from the woofer.

Jeff, to be fair I also didn't get the part with diffraction. What frequencies were equalised? So far I've seen regular 2nd order for the woofers. That's why I'm curious about the kind of shaping you have used.

Also we ca see some dip in woofers response beetwen 80-200hz but it is absent on the final measurement after crossover (loos like BS to me tough). Is this just because of boudary effect or because of 2nd order xover or because of additional equalisation?

PS. Do you know F3's of sealed versions of your speakers?
post #6133 of 9844
Quote:
Originally Posted by bwaslo View Post

The bumps above 500Hz could easily be flattened with some series resonant sections at the main terminals if you needed it flat. Better to just use a decent amp though.

I played around today. Using a single series LCR across the input comprised of .4mH, 25uF, and 20 Ohms will net this impedance:



This will work fine on either speaker - using the Definimax 4012HO or the Tempest with the Delta Pro 12A

Jeff
post #6134 of 9844
Quote:
Originally Posted by fakamada View Post

Jeff, to be fair I also didn't get the part with diffraction. What frequencies were equalised? So far I've seen regular 2nd order for the woofers. That's why I'm curious about the kind of shaping you have used.
Also we ca see some dip in woofers response beetwen 80-200hz but it is absent on the final measurement after crossover (loos like BS to me tough). Is this just because of boudary effect or because of 2nd order xover or because of additional equalisation?
PS. Do you know F3's of sealed versions of your speakers?

"Looks like BS"? Well, OK.

Woofers in boxes suffer more diffraction effects than what is typically called baffle step. Just as significant is a peak that develops in the response just above the step. This peak will typically be around +3dB. I don't really think about it in those terms though when I am designing a crossover; I simply optimized a circuit whose transfer function results in my target response. In this case the crossover is an acoustic 4th order Linkwitz-Riley (in-phase) crossover.

The circuit is not 4th order, but the combination of the driver's frequency response and the crossover transfer function results in this target response. The same can be said for the tweeter's crossover too. As I posted earlier, I did not use second order circuits. My circuit actually changes slope mid-way through.

As for the dip that is showing up around 200Hz in some measurements, that is a boundary reflection. It is in the room response curves. However, if I take near-field woofer measurements to splice onto far-field measurements for what I am calling "quasi-anechoic that dip (and / or peak) is not there. It is normal to see these changes when changing measurement methods.

I have not modeled these as sealed boxes. F3 will probably be around 80Hz, but the Q will be pretty low in these boxes. I can take a closer look at this later.
post #6135 of 9844
Quote:
Originally Posted by Erich H View Post

Dustin, this thread is mostly about the larger waveguide speakers. They're just now being finished up and the designers are currently explaining the designs. Even though there are a lot of choices, it's broken down into woofer size you might want, and then how much you want to spend for a speaker. Any of the designs will be great for the budget you have. There's no reason to worry whether one is better than the next model if the next model is twice the price. They're all very good for the price range you're hoping to stay in......or they wouldn't be listed. There are 2-3 designs that were worked on, but not listed. One was a smaller model, one was with a 10" B&C. They didn't bring enough to the table to justify the price, so they weren't done. If the speaker is listed it's a very nice speaker. The low price is just a plus when compared to commercial offerings.
So in the end, there might be 20 designs for the waveguide speakers, but only three per woofer size to give you a low, mid, and high priced option. I don't think it makes sense to only put up the highest priced model because many might not want to spend that much per speaker.
The other speakers your talking about normally have links to the designers page, or a link to a thread that discussed more about them. But even with that, most of the decision will have to be based on your own needs or own speaker style.
If you wanted some smaller speakers for a bigger room, you'd want to look at the 8" models listed on the site. I just got the photo uploaded for the 8" B&C, but still working on prices. The 8" Celestion has been up for quite a while.

Thank you for the explanation Erich. I think my problem is wrapping my head around the waveguide speakers and how they would compare to other designs and what they are meant for. To me it seems like a waveguide speaker is for a concert or auditorium. Other things, like how far do they need to be from back wall, do I need to toe them in (some say as much as 45 degrees). Do I loose the whole point of waveguides if I want 3 up front?

When I look at the osmtm or hitmakers and see a frequency response down to 40hz compared to a waveguide at 55hz, I then wonder if the efficiency of the wave guide is worth it. Or would I enjoy the sound of the other speakers? I guess I'm just looking on opinions on what to buy for music and tv. I really liked what I've heard about both the osmtm and the hitmakers. I also like the size of the 8" B&C.

Maybe I'll just order one of each and try them out. Once you have a price on the 8" B&C let me know and I'll order one.

Price isn't a big concern. I was going to go with some KEF Q300's up front. I did have the ability to listen to those and I really enjoyed them. But I don't want to buy them after reading all the good things about diy.
post #6136 of 9844
Quote:
Originally Posted by DustinF View Post

Thank you for the explanation Erich. I think my problem is wrapping my head around the waveguide speakers and how they would compare to other designs and what they are meant for. To me it seems like a waveguide speaker is for a concert or auditorium. Other things, like how far do they need to be from back wall, do I need to toe them in (some say as much as 45 degrees). Do I loose the whole point of waveguides if I want 3 up front?
When I look at the osmtm or hitmakers and see a frequency response down to 40hz compared to a waveguide at 55hz, I then wonder if the efficiency of the wave guide is worth it. Or would I enjoy the sound of the other speakers? I guess I'm just looking on opinions on what to buy for music and tv. I really liked what I've heard about both the osmtm and the hitmakers. I also like the size of the 8" B&C.
Maybe I'll just order one of each and try them out. Once you have a price on the 8" B&C let me know and I'll order one.
Price isn't a big concern. I was going to go with some KEF Q300's up front. I did have the ability to listen to those and I really enjoyed them. But I don't want to buy them after reading all the good things about diy.

OSMTM do not hit 40hz at any high SPL.. power compression kicks in way earlier than that. Try playing those speakers loud then do freq sweeps and youll get either power compression, port chuffing, or the speaker exhibiting mechanical noise. The worst part is this will certainly effect the higher frequencies. A 12" woofer isnt flinching when its doing extremely loud SPLs. Its an effortless sound and freq responses only tell an extremely small part of the story. Not a knock against the OSMTM/Hitmakers this is just the nature of the beasts between low sensitivity and high sensitivity speakers.
post #6137 of 9844
Quote:
Originally Posted by DustinF View Post

To me it seems like a waveguide speaker is for a concert or auditorium.

Yes, but the same performance characteristics give them several advantages for small rooms; read about it at gedlee.com.

Oh and Bill might did a nice writeup here http://www.diysoundgroup.com/forum/index.php?topic=20.0
post #6138 of 9844
I've updated the page for Jeff's speakers so you can now subtract off the CD and waveguide if you already ordered them. I think all the other models have those options already, but I'll be double checking everything tomorrow.

As mentioned, I bought all of the Definimax woofers that PE had in stock. But that wasn't very many. Of course Eminence isn't that far away from me or PE, so it probably won't take too long to get more in. There shouldn't be any problem keeping the Delta Pro's in stock because they seem to be a more popular woofer and PE might stock more of those. Personally, I'm going to be using mine in the home theater, so I'll be building the Delta Pro model for the extra kick.

By the way, these are fairly heavy woofers. I picked up a decent number of them in my car on Saturday and I do believe the back was sagging a bit! biggrin.gif
post #6139 of 9844
By the way, if anyone wants to write up an explanation about why the Overnight Sensations are listed with a lower frequency response, let me know. I'll create a Frequently Asked Questions page and put all the info there, and obviously give credit to whoever writes it up. If you haven't noticed, I'm not the best at getting my points across. biggrin.gif

While surfing the vast interwebs about a month ago, I noticed a website talking about the the same thing and they were bashing the big woofer speakers. They thought they weren't very good if they couldn't handle the same frequencies as the small 4" woofers. They actually had a link to Bwaslo's Deltalite speaker. I should try to find that forum.


If anyone wants to write up anything on DIY speakers, tips for building, why some speakers perform different than others, or anything else, I'll be sure to post all the articles in one place.
post #6140 of 9844
Erich,
You have a PM regarding some orders we have been discussing
post #6141 of 9844
Quote:
Originally Posted by DustinF View Post

I think my problem is wrapping my head around the waveguide speakers and how they would compare to other designs and what they are meant for.

First and foremost, a waveguide is intended to provide a similar directivity index between the woofer and tweeter, unlike flush mounting. This is true of everything from the wide dispersion waveguide speakers a la Revel and TAD, to the larger stuff in this thread. The SEOS specifically constrains the tweeter response to a 90 degree pattern - that is to say that the sound at 45 deg off-axis is 6db down in level, or something along those lines. The biggest advantage of this 90 degree pattern in a home is that it increases the direct-to-reflected ratio of sound at the listening point - giving a drier presentation that can be argued to be more accurate to the source material. The bigger you go, the further down in frequency you get to push the 90 degree pattern. A 12" two-way - like the Gedlee Abbey - helps keep this pattern down to near 1khz. The biggest advantages of controlling dispersion are seen above 700hz, because this is where not only timbre - but also stereo imaging cues tend to exist.

Large waveguide speakers use compression drivers, some of which allow for a low crossover frequency, which is how you can even use a 12" mid in the first place.
Quote:
Other things, like how far do they need to be from back wall, do I need to toe them in (some say as much as 45 degrees). Do I loose the whole point of waveguides if I want 3 up front?

As far as distance from back-wall, that will normally depend on who was designing the crossover. Some like to design with the assumptin that the speaker will essentially sit in a corner, while others don't. I'd say this kind of speaker is certainly less sensitive to placement than a narrow baffle, wide dispersion speaker though.

The 45 degree toe-in is recommended, yes. For a speaker with the correct horizontal polar pattern, it works out in a way that you get fairly equal amounts of sound from the nearest and further speaker - it gives a wide sweet spot. Without toe-in, someone sitting too far off from the further speaker will get a sound dominated by the nearer speaker. Nothing wrong with a center channel,.
Quote:
When I look at the osmtm or hitmakers and see a frequency response down to 40hz compared to a waveguide at 55hz, I then wonder if the efficiency of the wave guide is worth it. Or would I enjoy the sound of the other speakers? I guess I'm just looking on opinions on what to buy for music and tv. I really liked what I've heard about both the osmtm and the hitmakers. I also like the size of the 8" B&C.

On of my favorite speakers is a little 4" bookshelf that probably doesn't even go usefully below 70hz. Small speakers can sound great within their limits. But those limits exist, plain and simple. No subwoofer can correct for it nor can a big amp can correct for it. Efficiency and displacement just aren't there. Without efficiency, you run into thermal compression. without surface area, you run into over-excursion. These are real and audible.

Personally I do like for a speaker to get down to 100hz without the need for a vent. Below that, multiple subwoofers have real advantages.

The thing you need to realize though is that frequency response is "shaped" by different things. The crossover, and also the mechanical properties of the drivers. It may seem difficult for a speaker with a 12" midwoofer to fall off in frequency, but even that can be misleading. For a vented speaker, equalization above the tuning frequency is harmless if the headroom is there, so focus on the tuning rather than the F3. The 12" woofer has a LOT more headroom than a 4" or 5" woofer.
post #6142 of 9844
If anyone is going to want any of larger or smaller SEOS waveguides (including the SEOS-24), you should let me know as soon as possible because the pallet for the group buy is filling up.
post #6143 of 9844
Quote:
Originally Posted by Jeff Bagby View Post


Woofers in boxes suffer more diffraction effects than what is typically called baffle step. Just as significant is a peak that develops in the response just above the step. This peak will typically be around +3dB. I don't really think about it in those terms though when I am designing a crossover; I simply optimized a circuit whose transfer function results in my target response. In this case the crossover is an acoustic 4th order Linkwitz-Riley (in-phase) crossover.
The circuit is not 4th order, but the combination of the driver's frequency response and the crossover transfer function results in this target response. The same can be said for the tweeter's crossover too. As I posted earlier, I did not use second order circuits. My circuit actually changes slope mid-way through.

Jeff,

Did you use any damping material or the cabs were naked? in general, does cabinet liner affect the kind of diffraction artifacts you were dealing with?

thank you
post #6144 of 9844
Quote:
Originally Posted by zheka View Post

Jeff,
Did you use any damping material or the cabs were naked? in general, does cabinet liner affect the kind of diffraction artifacts you were dealing with?
thank you

I did not use any, nor would it help. This type of dffraction is too low in frequency for something like felt to assist, it is caused by the size of the baffle itself. All speakers on baffles deal with this to one extent or another.
post #6145 of 9844
Quote:
Originally Posted by Jeff Bagby View Post

I did not use any, nor would it help. This type of dffraction is too low in frequency for something like felt to assist, it is caused by the size of the baffle itself. All speakers on baffles deal with this to one extent or another.

makes sense, thank you.
post #6146 of 9844
Quote:
Originally Posted by Eternal Velocity View Post

First and foremost, a waveguide is intended to provide a similar directivity index between the woofer and tweeter.

At least as important is the "C" in CD, for constant directivity, which changes the tweeter's radiating characteristic from decreasing dispersion as frequency increases to relatively constant up to well past 10 kHz.
post #6147 of 9844
Erich, I hate to ask this of the busiest, most industrious person I've ever seen, but is anything happening with the XO boards?
post #6148 of 9844
Thread Starter 
perhaps most important is impedance matching the compression driver to the surrounding air. :-)
post #6149 of 9844
Thanks for everyone's explanation. That really helps!

Erich H- When you have 2 B&C 8" Speaker kits ready to go I'll take them and add a little extra for helping the community.
post #6150 of 9844
Quote:
Originally Posted by noah katz View Post

Erich, I hate to ask this of the busiest, most industrious person I've ever seen, but is anything happening with the XO boards?

Forum member Bwaslo hasn't been feeling the best in the past week. Once he feels better, he's going to design the actual crossover boards so I can send them to the manufacturer. After that, it should only take about 2.5 weeks to get them in. Obviously they aren't needed to make the kits. If you don't know how to solder them up, I'm sure a forum member could help. Right now, I just don't have the time to do that.

I'm guessing the boards will cost about $10 extra, depends on shipping. Worst case, if you really needed them I can ship the boards in an mid sized envelope once they arrive.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: DIY Speakers and Subs
AVS › AVS Forum › Audio › DIY Speakers and Subs › Hey guys...we need a little rallying here...