Three-way full range speakers

zingo

I'm considering building a full range, open baffle speaker based off the Tang Band W8-1808. The reviews are very good on it, and it's a good looking driver to book. However, knowing it has a limited top end, I thought it good to augment it with a tweeter (maybe ribbon) as is a fairly common design. My next thought was to add a bass bin to the cabinet and run a woofer (or two) driven off a plate amp to augment the bottom end. It would be a three way speakers, but only slightly as a majority of the frequencies would be handled by the full range driver. Has anyone tried or seen such a set up? It would basically be a full range augmented by a tweeter, with an attached subwoofer which seems like a decent concepts.

The speaker would be driven be my EL34 integrated, but I don't like running a pair of amps to do the woofers, thus my plate amp idea so the whole thing would just look like a tube amp running a pair of speakers; no external subwoofers needed.

halo71

Never seen anyone do it that way. Doesn't that kinda defeat the purpose of a full range speaker? Perhaps finding another driver to handle everything?

zingo

It seems to me no different than running a subwoofer with a pair of FRD speakers which is not uncommon. Am I wrong?

CoolJazz

You should really listen to the driver before being too sure about needing to augment at the top end Jake.

I've played with the 1772 version OB for some time now. The 1808 is really close to the same driver, with a higher Q, which should provide a fuller bottom end. I have also heard the 1808 briefly at a friends and just in the last few days got in one for myself.

Running the 1772 OB on about a 20" wide baffle, the 1772 was down, I think, 1db at 20k. On that width, it only made it down to 200. I should be able to report shortly how much the 1808 extends that down.

While running the 1772, I augmented the low end a couple different ways. For a while was playing with a Avantgarde bass module, which was easy and sounded good, but I think I preferred a line of OB bass drivers a bit more. Probably the matching OB character versus the sealed box. The hard part, in any case is of course the crossover being just right.

The quality of the sound from the TB's are very good. With the 1772, my biggest concern was getting the pop I like down towards the bottom end of where I was running it. Big dynamics, even at moderate levels, needs to be able to get that drive to be real. I'm currently running a whole line of cheap 8's OB and I get that in spades. Would sure like to be able to try a whole line of TB's OB!!

CJ

zingo

Thanks for the input. Trying the drivers alone and then playing with other options is probably a good idea.

You didn't think the sealed woofer was a good match to the OB drivers?

CoolJazz

Sealed bass is quick, accurate and has no one note tendency. It does match up pretty well to OB.

But OB bass has a different radiation pattern and just does sound different. It'd come down to taste in bass and how it plays in an individual room. OB bass tends to need more room than a box.

I could live with either when done right.

CJ

Joe08867

CoolJazz wrote: »

Sealed bass is quick, accurate and has no one note tendency. It does match up pretty well to OB.

But OB bass has a different radiation pattern and just does sound different. It'd come down to taste in bass and how it plays in an individual room. OB bass tends to need more room than a box.

I could live with either when done right.

CJ

+1 on this. OB bass is very room dependent. I would go with an OB woofer before a sealed one. The OB woofer will blend better into the sound. A sealed woofer may (?) have better punch but you will loose some of the feel of OB.

zingo

Do you have any suggestions for an 8" OB woofer?

Face

Here's a 3 way based on a FRD: http://www.ultraaudio.com/equipment/vsa_unifield3.htm

zingo wrote: »

Do you have any suggestions for an 8" OB woofer?

You won't get any bass from a 8" OB woofer. You may get away with a pair of 8's in a small room, but would need at least a pair of 12"'s or a 15" if you want any real low end.

FYI, you'll need a sub that can cross around 300-400hz as that driver will fall off pretty high in an OB.

dudeinaroom

Just wondering how an IB woofer would compare to an OB one. Seems like it could be a good match for a full range OB system, or I could be totally wrong.

megasat16

@ Dude,

IB is the term usually associated with multiple subwoofers and requires complete separation of rear and front wave of the subwoofers. IB setup requires two complete separate chambers (rooms) where subs are mounted in one room and the adjacent room act as a rear chamber (or box). The rear chamber acts as infinitely large enclosure for the acoustics suspension. This provides very good low end extension but makes the subwoofer output very low for a single driver IB. Therefore, you'll see IB setup has numerous subwoofers. I haven't come across anyone using regular woofers used in IB but I believe it can be done just as well as with the subwoofers.

An OB woofer setup is very much the same as you are using a driver in the Free Air loading and both the rear waves and the front waves are reflected in the same room. Therefore, the baffle must be large enough to separate the rear waves and front waves to have a good usable low end with the woofer. Since there is no acoustics suspension with the OB setup so the woofer electrical and mechanical parameters must be designed differently from the regularly woofers.

---

@ Zingo,

For 3 ways OB setup with Single FR driver, the usable low end output would be around 200Hz. You'll need to have a larger baffle and look at different baffle designs. There is an "H" frame design which will yield better bass response if you can't have a very large baffle.

As for the subs, there is a company called AE speakers (aespeakers.com) which makes and sell the OB drivers in various sizes.

There is also a Rythmik Direct Servo subwoofers that can be used for the sealed enclosure but subs can usually only go as high as 120Hz without high distortion. So, you will need to bring the low end of the FR driver down if you want to use with the subs.

Even though I haven't tried it, I think the OB sub from the AE speakers should go up to near 200Hz without much distortion.

One thing you need to consider is the XO design for the drivers and the sensitivity of the drivers you are using. One thing you don't want is your FR driver playing louder than your woofers or subs so you will want to make in room Frequency measurements. You can use REW or RTA if you have a measuring microphone to level match as much as you can. Or you can order a Dayton Omni Mic Kit from Parts Express for the measurements.

For the tweeters, you can add later. I found FR drivers have a good high end FR responses and may not require a tweeter. But it's nice to have a super tweeter once you feel comfortable with the FR driver.

Face

FYI on AE speakers, they have a huge backlog at the moment and you may have to wait 1-6 months for a pair of woofers. They do pop up on the used market time to time though.

dudeinaroom

Megasat,
I do know the difference in the designs and understand how each works. I was just thinking with an IB the speed of the drivers would not be compromised like that of an OB design, plus you would not have to worry about phase cancelation. It was just a thought since he said he was going to use a plate amp for the lows. You can yield decent results with a stereo pair of woofers in an IB, just have to make sure your woofers are close to the same vertical plane as you would be able to tell where the sound was coming from as they would be playing higher in the freq. range than IB subs. You will also have to play with time alignment via phase to get everything to gel well.

zingo

Here is my design for the speakers to run the W8-1808 full range, supported by the powered, sealed subwoofers. The best part would be since the bass bins would be powered by plate amps, the gain, crossover setting, etc could be adjusted on the fly to provide the best integration between the woofers and FRD. The picture isn't quite to scale as I still need to figure out exactly what the baffle for the FRD needs to be, but a good general idea.

megasat16

dudeinaroom wrote: »

Megasat,
I do know the difference in the designs and understand how each works. I was just thinking with an IB the speed of the drivers would not be compromised like that of an OB design, plus you would not have to worry about phase cancelation. It was just a thought since he said he was going to use a plate amp for the lows. You can yield decent results with a stereo pair of woofers in an IB, just have to make sure your woofers are close to the same vertical plane as you would be able to tell where the sound was coming from as they would be playing higher in the freq. range than IB subs. You will also have to play with time alignment via phase to get everything to gel well.

Oh Ok! :redface:

zingo wrote: »

Here is my design for the speakers to run the W8-1808 full range, supported by the powered, sealed subwoofers. The best part would be since the bass bins would be powered by plate amps, the gain, crossover setting, etc could be adjusted on the fly to provide the best integration between the woofers and FRD. The picture isn't quite to scale as I still need to figure out exactly what the baffle for the FRD needs to be, but a good general idea.

If you have something like that in mind,

Check out Linkwitz Lab.

http://www.linkwitzlab.com/

It's a very proven and well received design. I think it's easier to build a well proven design than trying to build one from the ground up that needs a lot of work.

http://www.madisoundspeakerstore.com/3-way-speaker-kits/orion-3.4-linkwitz-lab-3-way-kit-pair-drive-units-only/

Face

Check this out too: http://www.htguide.com/forum/showthread.php4?t=39342

CoolJazz

zingo wrote: »

Do you have any suggestions for an 8" OB woofer?

I've not done any bass drivers in 8". I have done a line of 4 econo 10" OB which worked pretty well. I had handy a 180hz crossover and used it between the 10's and the TB 1770. The high pass side filter was only a single hq cap, so a 6db slope going down on the TB. 18db on the LP for the woofs.

I like your drawing. The FR of course needs to be at seated ear level. I wouldn't rule out that pair of 8's (or maybe slip in 10's) being OB. If you don't go crazy on level, my experience is that the multiple of 2 OB drivers can do bass just fine. Watch the qts number and get the side walls back enough to keep the front profile slim, but have enough wrap around to be in the above 18" or so category and it's not at all tough to find drivers to make 45-50hz. With 6-8" FR drivers I do flat to 40 and much usable output lower. With 5 watt amp, I can play a Chinese whacking on a big drum that you can feel impact on the chest! Nobody that's heard 'em yet has asked for any more on the low end for music!

The above mentioned TB 1770's to either of several woofer systems, was the thing that left me wanting a bit more in that 125-250 area that's now absolutely fine. Don't know if a cross just a little bit higher would have worked better or not.

CJ

PS...if you could do 10's OB, then I'd look hard at the Hawthorne 10's. I'm in the middle of making a PPSL (a la Linkwitz) for a set of those.

Face

http://gr-research.com/sw-12-08-1.aspx

zingo

Thanks for all the comments guys and the link to those OB 8"s. I'd be interested to try a pair of those in each baffle and see how the bass turns out with the W8-1808 playing FR. The best part right now if I go ahead with this project is the speaker cabinet would be easy to make...

Clicking around on the GR Research website, I noticed their OB kits including the OB-7. On a side bar, has anyone heard any of those kits? Totally different design than the FRD, but nice looking none the less.

Face

FYI, you will still need some sort of filter on your FRD to prevent it from bottoming out.

megasat16

Mike, Absolutely Golden! There should be a High Pass XO above 100Hz or something around there for the FRD from bottoming out. It's really easy to over driven the FRD in the OB setup.

Mark@CoolJazz,

Wouldn't the FRD array beam the Highs? How do you take care of the comb line forming?

CoolJazz

Good questions Mega! This whole thing started with expectation of exactly that!

To back up a little, I'd built several types of OB already with several different drivers. The sound quality was interesting, very good even, but I kept coming up against wanting a little more down low. That impact thing. I don't usually listen all that loud, not more than life like but to be realistic I kept wanting that nice pop down lower.

Enter the TB which is a really, really nice sounding driver. Maybe not as startling clarity wise as a Lowther but without all those warts either. But the TB still raised that how to deal with lower ranges issue.

So I was hoping to find a match LF driver. I looked for a coax point source with identical LF driver and couldn't find what I was looking for. The closest I came to was trying the Hawthoren 10" coax and buy extra drivers without the compression driver. But the expense was just high enough to not jump into it, plus the question about the possible difference in the CD level versus the 3 or so 10" for the rest of the spectrum.

In looking at the TB, you can't help but wonder what it would do in multiples without the whizzer. But it's too pricey to do that too for me! So I ran into a driver with pretty broad specs that was a duo-cone and a nice high q. I order a half a dozen with the plan to try 3 per side with a center driver being FR and cutting the duo-cone off the drivers that'd be mounted above and below. But I wanted to listen to them as they were first. I cut a 20" wide board, 48" tall and mounted the 3 drivers on them to break in and listen to, before taking a knife to them. I left room between the drivers when I cut the driver holes so I could later cut the flat board apart and reuse it. Also, it left room in case I wanted to try larger sized drivers than 8's.

So even with extra spacing, a big no-no for line sources, I dropped them in to listen to. Much to my surprise, they were pretty pleasant to listen to! Very surprising, you can raise and lower your seating position and even with several inches between the drivers, from the listening position I couldn't hear any problems with comb filtering! I'd have bet on it being there! You have to approach the drivers to within a couple feet to get them to start seperating. In several months now, I've never yet detected any hint of comb filtering or lobing!

SQ, with a current source amp driving, actually was darn good! Then they started breaking in a getting better yet. So with room, I added a fourth driver to each side! Still just a flat board leaned against a speaker stand. SO much better than expected, the idea of cutting out duo-cones went away! Instead I started plotting for another driver expansion. You see, one driver sounded like a what you'd expect from a single cheap driver. Two was ok, but nothing we'd want to listen to for long. Three though, was getting there and four started to turn the trick! But with six I think it reaches that point of diminishing return. It's there! Efficient, LF extension, lower range dynamics, loudness if wanted and all with no crossover and wonderful soundstaging! Biggest down side is rolling off a little early! About 14K. Makes all material listenable and never harsh, but you do know it's not quite the sparkle on metalic "tings" that you want. So despite not wanting a crossover, I've added a rear firing small horn based driver bouncing off the back wall. Friends are now agreeing with me that it's not lacking at all now in highs!

BTW...my long term listening has been about 15 years with big Martin Logan electrostat's. While these don't have that kind of mid clarity....what do you expect for about $300 in drivers!! Yup....done on the cheap just to see what'd happen! Now you have to wonder what would happen with a better driver, like the TB??

Feel free to doubt one guy you don't knows description of the sq, but this concept does work pretty darn well. And in thinking about it, I kind of think that rolling in a tweeter for air is probably going to prove more successful than trying to augment down low. I believe it has potential to just be less noticable up high. But I'd prefer a broad enough driver to not need any cross at all!

CJ

zingo

Has anyone tried loading the TB FRD into a sealed box? I know it would remove the OB/bipolar magic, but running the TB FRD in a slim cabinet with powered woofers might make a nice package...

zingo

Or taking an easier way out and trying them horn loaded in a prefabbed enclosure? http://www.madisoundspeakerstore.com/full-range-speaker-kits/fostex-bk-20-cabinet-sold-flat-each/

dudeinaroom

Could also go with a transmission line, but your looking at a lot of work to get it right.

Face

dudeinaroom wrote: »

Could also go with a transmission line, but your looking at a lot of work to get it right.

http://www.hornresp.net.ms/

zingo

dudeinaroom wrote: »

Could also go with a transmission line, but your looking at a lot of work to get it right.

Like this? http://brinesacoustics.com/Pages/TT-2000/Main.html

megasat16

Mark @ CoolJazz,

Thanks for the detailed post. I agree the FRD array can sounds so good. I am in the camp of those who can't properly use know the audiophile terms to describe the sound quality. I am pretty certain your pretty good is the same definition as mine!

~ James

@Zingo,

I think it is easier to optimize the FRD in the TL Loaded or Horn Loaded designs. I almost forgot but there is 12" new Carver Amazing Platinum woofers that can be used for the OB woofer. They cost like $60 each and they are low distortion within reasonable SPL limits.

Jim Shearer

Zingo,

If you want to go w/ MLTL, then one of Bob Brines' model would do well for you.

If you want to make an OB, then check out MJK's site: http://www.quarter-wave.com/
Look at both the OB theory and project areas. I admit to being a shill for Martin; not just because he is a friend, but I have listened to several of his builds and also built a small passive OB based on his design (but slightly modified). His designs for H-frame bass using either Eminence Alpha 15a or the 18" Goldwood driver are excellent.

And if you want to get serious about speaker design, I can recommend MJK's MathCAD worksheets ($25) which run under MathCAD Explorer (free download).

Cheers, Jim