a DIY rant

[Swerd]

I can’t say whether this is a rant or a DIY topic. Call it a DIY Rant.

I went exploring at another audio forum’s DIY site and saw this thread. As I read it, I imagined just how much kool-aid the OP had been drinking (note his moniker and self-description). As I read further in the thread, I realized he was in good company. In fact, I felt like it was 1978, I was in Jonestown, and I was the only guy there who didn’t drink the kool-aid. I don't think I want to post anything there, so I'll complain about it here .

This guy proposes to build a massive 2-way speaker with a 15” woofer combined and a 1” compression tweeter mounted behind a large 12” wide horn or waveguide. He wants to use public address (PA) drivers in a 3 ft³ cabinet, for a home theater room 10’ 8” wide × 23’ deep × 8½’ high. (I found it amusing that the OP described his room dimensions in inches – too much Ritalin?) The size isn't unusual for a HT. What is unusual is that he plans to use PA speakers more suited for a large auditorium, or a large commercial movie theater in a normal sized room in a refinished basement.

The drivers & horn:
Acoustic Elegance TD15M driver
BMS 4550 Compression tweeter
SEOS 12 waveguide

Even though I’ve seen this before, I’m still shocked by people obsessed with idea of using PA style speakers for home audio. At several audio shows, I have seen the audiophile variation of this, large PA type drivers in large nicely veneered cabinets, at absurdly high prices. The concept (I use this term loosely) behind this has it that extremely sensitive speakers could be driven by very low powered single ended triode tube amps, in the 5-10 watt range, and that there was an audible benefit to this. I’ve heard more of these speakers than I ever want to describe, and all but one of them sounded positively awful, with a gigantic hole in the midrange!

The OP did mention this

“I'm a little nervous on the TD15 and SEOS12 however. The SEOS needs to be crossed above 950, and John recommends crossing the TD15 no higher than 1k.”

Now here comes the RANT. NO ONE in this thread mentioned or even asked if this 15” midwoofer could go high enough to allow crossing over to the 1” compression driver mounted behind the horn!

Am I missing something? Is there any sound thinking behind ideas like this? To be convinced, I will need to see some measurements. Because this speaker design is such an extraordinary idea, I think I'll need some extraordinarily good data.

 

[jinjuku]

The SEOS build as desinged by Jeff Bagby are gaining quite a bit of attention for their controlled directivity dispersion patterns. Let me know if you want a link or two for some more reading.

Also the QSC K series is garnering some attention for home HT use.

 

[Swerd]

The SEOS build as desinged by Jeff Bagby are gaining quite a bit of attention for their controlled directivity dispersion patterns. Let me know if you want a link or two for some more reading.

I think I understand the general idea behind controlled directivity, but I don't get:

• Why a compression tweeter in a CD mount would sound better than a more typical tweeter on a flat baffle.
• Why PA speakers better suited for large auditoriums would sound better that home audio speakers in a home setting.
• Why anyone would try and use a 15" woofer in a 2-way even if the tweeter might go as low 1 or 1.2 kHz.

Thanks for the offer of more links, but I'll pass. I am highly skeptical.

 

[lsiberian]

The only family member I have in the hobby loves horns. I see nothing wrong with it. Some folks like the sound and like the idea of having an efficient speaker. I'm not saying it's ideal, but it's a hobby and there is worse koolaid in this hobby than using a horn.

 

[Swerd]

The only family member I have in the hobby loves horns. I see nothing wrong with it. Some folks like the sound and like the idea of having an efficient speaker. I'm not saying it's ideal, but it's a hobby and there is worse koolaid in this hobby than using a horn.

Well, even though I haven't heard a horn I like, you may be right about the kool aid part. Any horn speaker, even with overpriced speaker cables and a flea-powered amp, is still better than drinking cyanide kool aid.

I wish there was a good beer analogy for this thread .

 

[Swerd]

The SEOS build as desinged by Jeff Bagby are gaining quite a bit of attention for their controlled directivity dispersion patterns. Let me know if you want a link or two for some more reading.

On second thought, please post those links. I may have my doubts about this type of design, but I couldn't call myself a skeptic if I didn't at least take a look.

 

[panteragstk]

It almost seems like a case of "mine's bigger than yours". I can't really understand why people ever used PA speakers in the home, unless they have a MASSIVE room and want high SPL. I've had a few people buy stuff from me for that reason, but I can count them on one hand.

The QSC K series is very nice, but from my experience with it almost any decent "home" speaker can beat it in SQ. Don't get me wrong, the K series is fantastic for a PA speaker, but even for PA usage they are limited on output. Using two K12's and two K subs we got them to choke when the SPL demand got high enough. All depends on the music we played, but anything with lower bass was a no go. They got a bit harsh at the top as well, but that was at VERY high SPL.

 

[panteragstk]

Well, even though I haven't heard a horn I like, you may be right about the kool aid part. Any horn speaker, even with overpriced speaker cables and a flea-powered amp, is still better than drinking cyanide kool aid.

I wish there was a good beer analogy for this thread .

Man, you guys are quick. Beer analogy would be buying a keg of Natural Light for one person when you could just get a few bottles Chimay Blue and be better off. I can't think of one better.

 

[Swerd]

Man, you guys are quick. Beer analogy would be buying a keg of Natural Light for one person when you could just get a few bottles Chimay Blue and be better off. I can't think of one better.

Good, I like that.

But in keeping with your "mine's bigger than yours" idea, it'll have to be an 11-pack of Chimay Blue .

 

[j_garcia]

The title says it all "end of upgradeitis" and THIS is his plan? Dude does not have a clue. Garage speaker 101, straight out of the 80s.

 

[Swerd]

The title says it all "end of upgradeitis" and THIS is his plan? Dude does not have a clue. Garage speaker 101, straight out of the 80s.

Thanks for putting it that way. It made me think about what got me mad enough to start this thread.

Even though the dude is still in the "Garage speaker 101" stage, I wasn't really annoyed at him. I don't know about you , but most of us were at that stage at some time in the past .

What set me off on that rant was that everyone else in that thread so readily agreed with him. No one addressed the critical question of how can you successfully cross over that 15" woofer to that tweeter. Instead, most posts I saw talked about how to cross over that 15" woofer to a subwoofer! Apparently he plans on SIX subwoofers. In a room less than 11' wide, where are all those dog house sized cabinets going to sit?

 

[Alex2507]

Is six subs too much?

 

[Dan]

Remember Swerd, your little brother has six subwoofer drivers (in two cabinets) too. I think this guy is a big believer in "This one goes to eleven!" Many other spinal tap lines like making your eardrums bleed also come to mind.

My beer analagy runs to chugging directly from the keg tap. While I personally never did that (that I remember) I know several respected people who have that skeleton in their closet

 

[Swerd]

It's strange how my online rants usually come when I'm sick. Yesterday I had a bad sinus headache and felt "poorly" in general. I attributed it to the damp cold weather. It never occurred that I was coming down with something. Later that night, I realized I had a head cold or flu. This morning, I'm certain of that. Oh well .

Remember Swerd, your little brother has six subwoofer drivers (in two cabinets) too. I think this guy is a big believer in "This one goes to eleven!" Many other spinal tap lines like making your eardrums bleed also come to mind.

Yes, the general unspoken theme for most people in that thread is that woofer size directly reflects the size of their genitalia. I laughed when the OP referred to that 15" PA woofer as a mid woofer . In that light, I'd be careful about bragging of your multiple 8" sub drivers . Still, having three available in one cabinet does suggest interesting possibilities .

As far as the beer analogy goes, a keg of Natural Light should be used to rinse out beer glasses after drinking real beer.

 

[slipperybidness]

The true end of Upgradeitis

 

[Swerd]

LOL

If he has one of those, there will soon be someone who "needs" seven.

I'm holding out until I can find some brackets so I can mount them on the wall.

 

[Dan]

I think this is clearly where that guy needs to go for the next upgrade:

 

[Rickster71]

If anything, this thread proves how analogous beer and electronics really are.

 

[jinjuku]

While in specifics I agree that the builder is pushing it with trying to match those drivers up without having a huge dip in the x-over region to each their own. I've been done giving advice where none is asked for.

 

[j_garcia]

Thanks for putting it that way. It made me think about what got me mad enough to start this thread.

Even though the dude is still in the "Garage speaker 101" stage, I wasn't really annoyed at him. I don't know about you , but most of us were at that stage at some time in the past .

Yep, been there, done that. Good way to learn what doesn't sound good

What set me off on that rant was that everyone else in that thread so readily agreed with him. No one addressed the critical question of how can you successfully cross over that 15" woofer to that tweeter. Instead, most posts I saw talked about how to cross over that 15" woofer to a subwoofer! Apparently he plans on SIX subwoofers. In a room less than 11' wide, where are all those dog house sized cabinets going to sit?

Either he knows what he is doing and that is exactly what he is after (though I doubt that, but it could happen), or he is just getting started. Yes, that nobody corrected him is odd, but it IS AVS after all