Change of plans...

[Hi Ho]

I was planning on building a set of Ascendant Audio Arbiter MTM speakers. However, since I have been unable to get ahold of them for three weeks, I am going to give up on that idea. Plus, according to people on their forum, they are sold out of the 6.5" Poly Mids, the main component in those speakers, and do not plan on making anymore. I have had very positive experiences with Ascendant in the past. My Ascendant Atlase 12" subwoofer driver is one of the best built and best sounding drivers I have ever seen or heard. Recently, however, I have not been able to recieve any customer service and their site has not been updated in over a month. I will withold final judgement for a later date but I need to build some speakers within the next two months if they are going to be used as my senior project.

So, I have been looking at Seas drivers, particularly the L22RNX/P 8" and the L18RNX/P 7" (or is it 6.5"... conflicting info between Madisound and Seas site).

Are these good drivers? They are both virually the same price. They appear to be of good quality. I know Seas has an excellent reputation.

If I go with the Seas drivers I would go with only one woofer in the mains instead of two. That leads me to another question. Having a center speaker with one (or two) 8" drivers would simply be too big for my current setup. My goal here is to have a matched set of three speakers for my front soundstage. If I made a center in an MTM alignment with, say, two smaller woofers, could I acheive a timbre matched system? Would it work to build the center just like the mains and set it on its side?

Now comes the tweeter choice. Both of those woofers go up to about 2000hz. Many of the Seas tweeters go down to about 2000hz. What would you recommend for a tweeter? A Seas model? Another brand? I don't want to go over $30 a piece for the tweeters as I am attempting to keep costs about the same as they were for the Ascendant set.

The recommended enclosure for the 8" woofer is 1.9^ft with a 2" FP at 4.3" long. Does that sound about right? I will try modeling it in WinISD but I'm not sure what the Xmax is. Seas gives "linear coil travel" and "maximum coil travel". Which one would be equivalent to Xmax?

The final issue is crossover design. I don't know how to design a crossover. I know there are kits, designs, and prebuilt crossovers available but I want the crossover to be just right. Also, the PDF specs sheet for both of the woofers says the following:

"The cone break up modes at higher frequencies call for special attention in the crossover design work."

What exactly is this "special attention"?

I know I'm getting in deep for my first DIY speakers but that is what I am trying to do. In using them as my senior project, I am supposed to challenge myself and strain my abilities.

Any advice would be appreciated.

 

[j_garcia]

What is your planned total cost per speaker roughly? About $300? I would HIGHLY recommend sticking with the kit idea... takes most of the guess work out. The crossover can be the difference between a good and a bad sounding speaker, and crossover design for a good speaker is not as simple as it may seem. It is not just about the x-over point - there are a lot more factors that have to be considered and measured as a complete speaker.

I personally would probably not go with an 8" driver for mains. A 6 1/2 in a properly tuned enclousure will give plenty of bass and better midrange than the typical 8".

Special attention likely means you won't want that 8" playing very high, so your tweeter needs to play low enough to blend well or you will need a 3 way design.

SEAS are great drivers, but great drivers alone don't make a great speaker.

 

[Hi Ho]

Do you have any recommendations for a good 6.5" driver? I like the high Xmax of the Seas drivers that is comparable to the Ascendant drivers.

I very well know that good drivers don't make a good speaker without the proper enclosure and crossover. However, if I never try, how can I learn? Sure, a kit would be the easier route and if there is a really good kit in my price range I would be willing to go that route.

My price range is not $300 per speaker. With the Ascendant kit, the total cost including MDF, veneer, and all other hardware, was to be about $550 for three speakers.

Do you think it is possible to build a set of speakers that will outperform my current Advents in my price range? The main problem now is my Polk CS1 center. I do not like the sound of that speaker and it does not match the Advents in any way. The Advents are far superior. I want to finally have a matched set of speakers.

 

[j_garcia]

What I was getting at is, there can be a lot of trial and error when designing your own speaker/x-over. You'll need at least some basic gear to measure your results so you know what it is that you are getting with your final design. If you are looking to really get into this, I'd say you'll want to start by researching what it takes to design a crossover and then decide.

$550 for 3 might be tough. Check out the GR Research site. A pair of A/V-1s and a A/V-3s with precut front baffles and magnetic grilles would be $513, not including enclosures or finish (which ends up determining your final cost). Or you could build 3 A/V-1s for a little less.

Check Madisound and Parts Express also for various kits.

 

[Hi Ho]

One thing is for certain, I will be building the cabinets. I do not want prebuilt boxes or baffles.

I see the AV2 kit is $300/pair plus $150 for a single. That would give me three speakers for 450 plus the cost of the other components. That is about the same price as the Ascendant kit.

Have you heard these speakers? Do they have a good reputation?

EDIT: I just noticed that the AV2's are 4 OHM speakers. In other words, I may be needing a new receiver and maybe external amps to run three of them.

 

[Rip Van Woofer]

The Seas 27TDC or 27TDFC tweeters are a bargain (I think a bit more than $30 but less than $50) from what I've read. They measure nearly as well as the very expensive and superb Seas Millenium tweeters. I have not tried them, though.

I built some speakers a couple of years ago with the Vifa D26TG-35-06 tweeter at about $30 ea. and liked their sound.

Take a look at "Mark K's Speaker Site": http://206.13.113.199/ncdiyaudio/mark/index.htm

He does extensive tests of drivers. An excellent resource.

 

[Hi Ho]

Thanks for the link RipVanWoofer.

I guess my question now is whether or not this project would even be worth it. I don't want to spend money on something that won't sound as good as what I have now. The Advents set the bar high. Would it be better to wait until I can afford a higher end set? The problem with that is I want a better sounding center now. I could buy a matching Advent off Ebay but I seriously doubt my receiver (or any receiver) would be able to power three of them.

EDIT: OK now I'm really thinking. Is it in any way advisable to run a Advent Smaller Loudspeaker on it's side from the center channel amp of a Panasonic SA-HE100 receiver? Any receiver?

 

[j_garcia]

EDIT: I just noticed that the AV2's are 4 OHM speakers. In other words, I may be needing a new receiver and maybe external amps to run three of them.

That's why I recommended the A/V-1s; they are 8 Ohm. The only thing they give up to the A/V-2 is sensitivity. The A/V-3s is also 8 Ohm, but gives up some bass extension even to the A/V-1s.

My main system uses 5 A/V-2s. They are amazing speakers. They offer precut baffles because most people don't want to buy the router bit to make the cut that allows the tweeter to be flush so the drivers have the correct center to center spacing.

 

[Swerd]

Too bad about the Ascendant Audio flame out. You are smart to heed the warning signs. Those MTM speakers may have been a good deal, but in the long run, I think you may prefer the sound of coated paper or aluminum woofers over polypropylene.

j_garcia and Rip Van Woofer have been giving you good advice. The GR Research M-130 woofer is an excellent coated paper 5¼" midwoofer at a very low price. The Seas aluminum woofers are also excellent, but do cost more. You might also have a look at the various designs made with the new Dayton RS series aluminum woofers. Parts Express designed them to compete directly with the Seas aluminum drivers. They perform well and cost much less.

See http://www.htguide.com/forum/showthread.php4?t=11321 for an MTM design with the Dayton 6½" RS and the RS tweeter or one of the Seas tweeters. This web site seems to specialize in various designs using the Dayton RS drivers. Have a look.

Also check out Roman Bednarek's page comparing some of the various crossover designs using these same Dayton drivers http://www.rjbaudio.com/RS180MTM/rs180-rs28-mtm.html

Have fun.

 

[Hi Ho]

Do you think those designs will sound better than my Advents? I connected one of my Advents to the center channel and it's like I have a whole new system. I am really considering buying some identical Advents on Ebay and waiting until I have more funds to build some speakers down the road.

 

[j_garcia]

Sounds like a plan to me man!!

 

[jaxvon]

The "special attention" is due to the resonance at certain frequencies. The magnesium Seas drivers that are used in the Linkwitz Orion (and many other super-hi-fi speakers) have a resonance at 5kHz that must be accounted for. Linkwitz uses a notch filter in the active crossover, you may wish to do the same.

 

[Swerd]

Do you think those designs will sound better than my Advents? I connected one of my Advents to the center channel and it's like I have a whole new system. I am really considering buying some identical Advents on Ebay and waiting until I have more funds to build some speakers down the road.

I haven't heard Advents in a looong time, so I can't answer you. You've already heard that they are better than your Polk center speaker. That may be all you need to know for now.

I forgot to add another link for an MTM design that uses the Dayton RS180s (6½") and the RS28 tweeter. It is the Dr. K's MTM in the Parts Express project showcase. I have heard this design in a demonstration with and without a subwoofer. They are excellent either way.

When you mentioned using an 8" aluminum in a 2-way design, you asked about Seas' warning that "special attention" was required. Mark K has an example of that http://206.13.113.199/ncdiyaudio/mark/RS225_RS28A_updates/dayton_reference_rs225.htm. He uses a Dayton RS225 (8") in a 2-way with a very steep crossover, called a Cauer/elliptic filter. If you look at the unfiltered frequency response curve for the RS225 driver at the PE website, you'll see large nasty break-up peaks beginning above 3 kHz that peak out above 95 dB in the 6-8 kHz range. The nominal sensitivity of this speaker below 1 kHz is 86-87 dB. The break-up noise has to be aggressively filtered out. Compare them to the same freq range on any standard 8" paper speaker and you'll see why this is such a problem.

Good luck with you speaker building efforts and keep us posted.

 

[Rip Van Woofer]

The Advents were excellent speakers in their day (I owned a pair of the original Large Advents for about 30 years) but progress has been made since then. It is entirely possible to surpass them with a good DIY speaker using good drivers.

I hope you have given up on designing your own crossover. If so, you can stop reading here.

However, if you still want to roll your own crossover, I have an out-of-left field suggestion: Buy an active crossover unit and bi-amp your speakers.

Designing a passive crossover is not a trivial exercise, and as pointed out earlier involves a lot of trial and error. Every iteration of your design will require more parts, meaning money (have you priced the large inductors typically needed for the woofer section?) not to mention time and frustration.

However, you can buy something like the Behringer CX-2310 new for about $90. That might be less than the parts for your passives. Even less used on eBay. Then your trial and error will consist of simply twiddling knobs (and doing measurements, of course).

Yes, you'll have to buy amps but watts are cheap these days. Especially used. And you don't need crazy powerful amps or even especially fancy ones. Coupling an amp directly to its driver without a passive xover makes an easy load for any amp.

I am driving my state of the art, fully active three way tri-amped speakers with DIY 60 watt per channel amps. They can produce enough clean SPLs to crack plaster!

Active crossovers are inherently superior to passive crossovers. There are many reasons for this -- more than can be enumerated here. Audioholics has articles and links to explore the subject further.

 

[Hi Ho]

The Advents were excellent speakers in their day (I owned a pair of the original Large Advents for about 30 years) but progress has been made since then. It is entirely possible to surpass them with a good DIY speaker using good drivers.

I don't doubt that at all. However, I am going to wait until I have a bigger budget and can build really nice speakers.

An active crossover sounds like a very attractive option. Thanks for pointing that out.

 

[annunaki]

I have been thinking of doing just that Rip. I was thinking of doing a two-way Speaker for each of my locations, with a two channel Behringer A500 on each one. I think I would need 5 crossovers though. That is 1350.00 (5.1) without the drivers or building the speakers. I am still contemplating it though. I was thinking of trying it with one pair to start. Any specific solutions you would suggest. Thanks.

 

[Hi Ho]

I bought another pair of Advents. I couldn't resist. At $106 w/shipping, THIS pair should keep me happy for a while, even though I don't know what to do with the extra speaker.

 

[Rip Van Woofer]

I have been thinking of doing just that Rip. I was thinking of doing a two-way Speaker for each of my locations, with a two channel Behringer A500 on each one. I think I would need 5 crossovers though. That is 1350.00 (5.1) without the drivers or building the speakers. I am still contemplating it though. I was thinking of trying it with one pair to start. Any specific solutions you would suggest. Thanks.

I think you'd only need one crossover per pair, wouldn't you? The Behringer crossover I mentioned is a stereo two-way or mono three way unit. And I think it also has a sub out. If not, another of their models does.

 

[WmAx]

I think you'd only need one crossover per pair, wouldn't you? The Behringer crossover I mentioned is a stereo two-way or mono three way unit. And I think it also has a sub out. If not, another of their models does.

If you are referring to the DCX 2496, it should be noted that it is perfect for this kind of application because DCXs can be daisy chained to use one as the master control with others used as slave devices. Also, the DCX has 3 analog inputs and 6 analog outputs, which can be configured in any combination desired. Most units only have 2 analog inputs. This means for example, one DCX could be used for the mains as a 3 way, and one could be used for the 2 surround speakers + center channel, assuming that the surround and center are 2 ways.

-Chris

 

[annunaki]

If you are referring to the DCX 2496, it should be noted that it is perfect for this kind of application because DCXs can be daisy chained to use one as the master control with others used as slave devices. Also, the DCX has 3 analog inputs and 6 analog outputs, which can be configured in any combination desired. Most units only have 2 analog inputs. This means for example, one DCX could be used for the mains as a 3 way, and one could be used for the 2 surround speakers + center channel, assuming that the surround and center are 2 ways.

-Chris

Chris,

So If I were doing two way speakers all around, I could get by with two DCX 2496, correct? And, it would give me the option to go with three-way fronts in the future? I would just need ten channels of amplification then. This is sounding better the more I think of it. I have my drivers picked out, this makes the decision that much more tempting. Thanks for your time. Sorry Hi Ho for butting, I didn't mean to.