T18 crossover question

For livingroom sound better than in a theatre.
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Dan_S
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T18 crossover question

#1 Post by Dan_S » Sat Nov 27, 2021 7:01 pm

Hello everyone!

Can I crossover the T18 at 300Hz? I have a pair of them, and the graph on the website only goes up to 200Hz (even though it's flat!), so I'm hopeful it doesn't roll off too much.

Thanks in advance!
Current builds in use:
2 x T18

Past builds:
2 x SLA
Omni15
Autotuba

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Tom Smit
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Re: T18 crossover question

#2 Post by Tom Smit » Sat Nov 27, 2021 9:03 pm

You could do that, buuuut....it is not recommended. The sound wouldn't be that good, and it make it easy to locate the sub, sound-wise. Subs should be crossed at something lower than 125 hz.
Last edited by Tom Smit on Sun Nov 28, 2021 12:47 am, edited 1 time in total.
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Dan_S
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Re: T18 crossover question

#3 Post by Dan_S » Sat Nov 27, 2021 9:59 pm

Thanks Tom. Rather than using them as subs I was thinking of using them more as bass drivers. I must admit I haven't tested them at that frequency, but I can give it a try and post my results :)
Current builds in use:
2 x T18

Past builds:
2 x SLA
Omni15
Autotuba

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Seth
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Re: T18 crossover question

#4 Post by Seth » Sun Nov 28, 2021 3:44 pm

Dan, I've tried crossing over my T39 as high as 200Hz and it sounds really good. Now, this is with the top mounted right above it, so being locatable wasn't really a concern. That said, from a subwoofer placement standpoint, under the main speaker nearly never provides optimum sub output and sub performance will usually suffer a bit. Still doesn't mean it can't or wont work. It's just not recommended, or is recommended not to.

Since you have them, it certainly wouldn't hurt to try it out and see what you think. However, this same question comes up a few times a year and I can't recall a single time that it was ever given the greenlight or someone reporting back favorably. Although, I can't recall an unfavorable report either. So, I look forward to hearing how it goes for you :thumbsup:
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Dan_S
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Re: T18 crossover question

#5 Post by Dan_S » Sun Nov 28, 2021 5:09 pm

Thanks Seth! I have no problem with giving it a try - to be honest, I think I've been using the T18s more as woofers than subs for quite a while...whatever I've stacked on top of them has allowed me to place them in a typical sub fashion anyway so there's always plenty of Bass (I usually have to drop the level by at least 3db) :)

Once I've got everything together, I'll report back with my findings :)

I remember with the AutoTuba you can mount it firing down at the floor for increased extension. Would this apply to the T18 if that were ever a concern?
Current builds in use:
2 x T18

Past builds:
2 x SLA
Omni15
Autotuba

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Dan_S
Posts: 108
Joined: Mon Sep 10, 2007 1:57 pm
Location: Burlington, Vermont, USA
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Re: T18 crossover question

#6 Post by Dan_S » Mon Dec 13, 2021 7:45 am

So I'm going to conclude that yes, the t18s can cross over at 300Hz :) My receiver doesn't have a parametric crossover though, so it's crossing over at 400Hz, so there might be a slight loss of information that high up (not that I've measured, and I can't really "hear" anything missing apart from a slight lack of Bass punch), but it's worth trying!
Current builds in use:
2 x T18

Past builds:
2 x SLA
Omni15
Autotuba

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