Trying to convince a newbie to not “rebuild” a pair of Def Tech BP2004 TL’s

[Pandaman617]

I recently sold a pair of Def Tech BP2004 TL’s to a newbie enthusiast. He’s a guy who is certainly a skilled carpenter in terms of home remodeling but has never built a loudspeaker. He did build a subwoofer box which has a car audio Alpine Type R in it based on the Home Theater Guru’s “Hammer” DIY subwoofer build. Anyways, without the means to measure any of the drivers, current in room frequency response or any of the other variables that come with building speakers he has informed me he is going to build new cabinets for them with thicker MDF and new crossovers. I’ve been into home theater for a bit now but have only built my own crossovers, I have yet to build my own loudspeakers but from what I can gather it isn’t a simple operation and given his lack of proper tools and experience I told him that the best outcome here is that the speaker sounds slightly worse with the worst outcome being it’s ruined. Am I wrong here?

 

[slipperybidness]

You are correct, and the challenge here is going to be even greater since they are bipoles.

Point him to a speaker kit from parts-express or meniscus audio instead!

 

[Pogre]

Sounds like a mess to me. Perhaps if he keeps the internal volume exactly the same in the new cabs and rebuilds identical crossovers it would work, but any change, any at all, to the original parameters will require designing new crossovers based on the t/s parameters of each driver and how they will act in the new enclosure. The drivers may not even work with the new cab.

 

[Pandaman617]

Thanks guys. I’ve been trying to be polite and not rude or arrogant but I can only repeat the same advice so many times

 

[Pogre]

Thanks guys. I’ve been trying to be polite and not rude or arrogant but I can only repeat the same advice so many times

Just run t/s parameters by him, what they are, and how important it is to match each driver to a specific volume as well as each other. Crossovers are designed to work very specifically with the internal volume of a cab and the other drivers. Even a small modification to any parameter will require a completely different crossover.

 

[Pandaman617]

Well I showed him this forum just to elaborate on the fact that it’s not just me saying it’s a highly technical process. The response was along the lines that he knows what he’s doing. Oh well, I made $300 off a pair of speakers I snagged off CL for $100 so it worked out for me. Bummer they’ll be ruined.

 

[Pedro Alvarado]

Am I wrong here?

you sir are 100% wrong here!
he is going to do it and it will be the best thing he has ever heard!

 

[Pogre]

you sir are 100% wrong here!
he is going to do it and it will be the best thing he has ever heard!

That's funny, but I was thinking the exact same thing. They might end up with a fr that looks like a mountain range, but he's likely going to insist they're vastly improved, if not the best sounding speakers he's ever heard. Call it expectation bias or placebo. We've seen some pretty crazy hack jobs posted up here that were supposedly amazing.

I'm not even kidding. That's an actual pair someone hacked together, posted them here and swore they're the best they'd ever heard. To quote, "highs like SSSSSS and bass like B-B-B-B-B-B!!".

Show your friend these posts too when he says it... lol.

I imagine your friend's work will be much nicer than those. My point is "sounds amazing" is pretty damned subjective, but there are objective metrics like a flat fr that predict how well a speaker will perform. Unless he understands t/s parameters and has experience building crossovers from scratch the new cabs have to have the exact same volume, and driver configuration or its gonna be a mess.

 

[Pandaman617]

That's funny, but I was thinking the exact same thing. They might end up with a fr that looks like a mountain range, but he's likely going to insist they're vastly improved, if not the best sounding speakers he's ever heard. Call it expectation bias or placebo. We've seen some pretty crazy hack jobs posted up here that were supposedly amazing.

View attachment 49823

I'm not even kidding. That's an actual pair someone hacked together, posted them here and swore they're the best they'd ever heard. To quote, "highs like SSSSSS and bass like B-B-B-B-B-B!!".

Show your friend these posts too when he says it... lol.

I imagine your friend's work will be much nicer than those. My point is "sounds amazing" is pretty damned subjective, but there are objective metrics like a flat fr that predict how well a speaker will perform. Unless he understands t/s parameters and has experience building crossovers from scratch the new cabs have to have the exact same volume, and driver configuration or its gonna be a mess.

I stared at this for a while and the next thing I knew I woke up in a hospital bed with blood running from my eyes.

 

[Pogre]

I stared at this for a while and the next thing I knew I woke up in a hospital bed with blood running from my eyes.

Ha! I managed to dig up the original thread! This link will take you right to the post where he first uploads the images, but the whole thread is worth a read for a good laugh.

Would wiring 4 super tweeters per speaker box increase life of tweeters?

Made my own box for those lowest lows and the finest highs "SSSSS" like I never heard. Just gotta cut some holes for my super tweeters and I'm done! Ha! When I was a kid, I built something just like that in electronics class, they said we couldn't use wood but if we wanted to have music in...

forums.audioholics.com

We had some fun in that one, lol.

 

[Pandaman617]

We had some fun in that one, lol.
[/QUOTE]

Holy crap that thread is GOLD! I’m astonished that clearly superior engineering hasn’t ever caught on at RBH or Revel.