THT LP - End or Side Port?

For livingroom sound better than in a theatre.
Post Reply
Message
Author
jerrymcdougal
Posts: 6
Joined: Sun Jan 06, 2019 2:26 pm

THT LP - End or Side Port?

#1 Post by jerrymcdougal » Sun Jan 06, 2019 5:47 pm

I'm going to be building a THT LP. 24" with the Dayton RSS390HF 15". Before ordering a flat pack, I'm wondering if end port or side port is ideal for my room. I'll be placing it vertically in the corner, however my room only has approx 14" of space above/below the cab, not the recommended 16-24". Would side port be ideal in this case?

Are there any performance differences between end/side port?

What would the ideal placement/direction be to put the sub? Is end port facing up/down going to give me any better or worse performance than side port facing the corner, along one wall?

Options are:

A) Vertical, end port facing up (into drywall ceiling) with only 14" to ceiling.
B) Vertical, end port facing down (carpeted concrete basement floor, drywall walls) with only 14" to floor.
C) Vertical, side port facing the corner (drywall walls, concrete carpeted floor).

Thanks!

User avatar
BrentEvans
Posts: 3025
Joined: Thu Oct 09, 2008 10:38 am
Location: Salisbury, NC

Re: THT LP - End or Side Port?

#2 Post by BrentEvans » Sun Jan 06, 2019 6:43 pm

That actually probably has more to do with the other dimensions of the room than the ceiling height. There are two things you can do to hedge your bets.

First, you can always build legs or wall mount the thing so that it butts up against the ceiling. That would give you far more than minimum clearances.

Second, there’s no reason you can’t build it as a convertible. You would build it so that you can use a the same panel to close off the end and the hole you cut in the side for a side exit. This is a low pressure area of the horn so simple wood screws are all you need to “seal” it. No gaskets or special considerations would be required to simply move the end panel. That way, you can test it one way, convert it, and test the other way, and pick which one works best.

In all reality, you probably won’t be able to hear any of the differences except distance off the floor. That would move the room modes around a bit.
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.

jerrymcdougal
Posts: 6
Joined: Sun Jan 06, 2019 2:26 pm

Re: THT LP - End or Side Port?

#3 Post by jerrymcdougal » Sun Jan 06, 2019 7:55 pm

BrentEvans wrote:
Sun Jan 06, 2019 6:43 pm
That actually probably has more to do with the other dimensions of the room than the ceiling height. There are two things you can do to hedge your bets.

First, you can always build legs or wall mount the thing so that it butts up against the ceiling. That would give you far more than minimum clearances.

Second, there’s no reason you can’t build it as a convertible. You would build it so that you can use a the same panel to close off the end and the hole you cut in the side for a side exit. This is a low pressure area of the horn so simple wood screws are all you need to “seal” it. No gaskets or special considerations would be required to simply move the end panel. That way, you can test it one way, convert it, and test the other way, and pick which one works best.

In all reality, you probably won’t be able to hear any of the differences except distance off the floor. That would move the room modes around a bit.
Thanks for the reply Brent!

If I mounted it butted up to the ceiling, pointing down, I would still only have 14" from port to floor, sound like you think that will be sufficient? The room is in my basement, and considering this beast is 6' tall, and the room if finished drywall under joists, it's about 7'-2" high in all. Giving me that 14" of clearance. I know this is a beast of a sub, but considering how close some downward firing commercial subs are to the floor, it seems like 14" should be sufficient, but I'm not expert with horns, this is my first horn venture.

The convertible idea is a possibility for sure. I was planning on buying the flat-pack from speakerhardware.com. I have most of the tools to build it myself, but considering how relatively complex this build is, the cost of the flat pack seems worth it. I've built a couple 8x12" guitar cabs, 4x12's, 2x12's, and 2x15"s before, but this has lots of complex angles and such that I'm not super comfortable with, given my tooling and experience.

Glad to hear that you think either way won't be a massive difference though, that's what I was hoping to hear. Corner loading sounds like it's more forgiving than I had previously imagined.

I'll be powering the THT with a heavily modded/rebuilt Adcom GFA-555, which should provide more than enough power. It won't break a sweat, as it does ~900W bridged at 4ohm. I may even end up using just one channel, due to the efficiency of the THT. May add a MiniDSP if necessary.

User avatar
Tom Smit
Posts: 6714
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: THT LP - End or Side Port?

#4 Post by Tom Smit » Sun Jan 06, 2019 9:59 pm

First: welcome to the forum!


Second: would you consider laying it flat against the ceiling? That would give about 5 feet to the floor along it's length.
TomS

jerrymcdougal
Posts: 6
Joined: Sun Jan 06, 2019 2:26 pm

Re: THT LP - End or Side Port?

#5 Post by jerrymcdougal » Sun Jan 06, 2019 11:22 pm

Tom Smit wrote:
Sun Jan 06, 2019 9:59 pm
First: welcome to the forum!


Second: would you consider laying it flat against the ceiling? That would give about 5 feet to the floor along it's length.
Thank you! First post, as you noticed.

I never really considered the ceiling. Seems like it would be an awful lot of work/fuss to suspend such a heavy unit from the ceiling. I was thinking a "pillar" in the corner of the room would look most architectural and integrated. Do you mean to imply the distance from the port is indeed quite important, to go to such lengths to have 5ft clearance?

Thanks!

User avatar
Tom Smit
Posts: 6714
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: THT LP - End or Side Port?

#6 Post by Tom Smit » Mon Jan 07, 2019 9:12 am

jerrymcdougal, it was just a suggestion in case you wanted that distance from the wall, using the end-fire cab. Putting it up at the ceiling would give you clearance on the floor for other things.
The "distance from the wall location" benefits can be best answered by Bill.
TomS

User avatar
BrentEvans
Posts: 3025
Joined: Thu Oct 09, 2008 10:38 am
Location: Salisbury, NC

Re: THT LP - End or Side Port?

#7 Post by BrentEvans » Mon Jan 07, 2019 5:06 pm

Another option would be to put the cabinet OUTSIDE the room and fire through the a wall, or the ceiling or floor. I've done this plenty of times and it works quite well. The biggest pain is getting a reasonable seal around the hole between the two rooms. If your carpentry skills are reasonable, you can get a tight enough seal with a pressure fit for acoustic purposes, but I'd probably want to add some expanding foam if it were going into an unheated space, or into another room where noise might be a concern.

That brings up an interesting question. If you did do an install like that with the bulk of the cabinet in another room, how much leakage would you get from physical acoustic coupling. I know the subs aren't supposed to vibrate, but surely there would be SOMETHING.... I've never experienced it with the installs I've done but those were mostly in unused spaces so it's not something we really looked at.
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.

jerrymcdougal
Posts: 6
Joined: Sun Jan 06, 2019 2:26 pm

Re: THT LP - End or Side Port?

#8 Post by jerrymcdougal » Tue Jan 08, 2019 6:27 pm

BrentEvans wrote:
Mon Jan 07, 2019 5:06 pm
Another option would be to put the cabinet OUTSIDE the room and fire through the a wall, or the ceiling or floor. I've done this plenty of times and it works quite well. The biggest pain is getting a reasonable seal around the hole between the two rooms. If your carpentry skills are reasonable, you can get a tight enough seal with a pressure fit for acoustic purposes, but I'd probably want to add some expanding foam if it were going into an unheated space, or into another room where noise might be a concern.

That brings up an interesting question. If you did do an install like that with the bulk of the cabinet in another room, how much leakage would you get from physical acoustic coupling. I know the subs aren't supposed to vibrate, but surely there would be SOMETHING.... I've never experienced it with the installs I've done but those were mostly in unused spaces so it's not something we really looked at.
Now there's an idea! Right beside this room is a storage/furnace room, which would actually be ideal for such a thing. Hmmmmmmmmmm. I think you're on to something there!
Tom Smit wrote:
Mon Jan 07, 2019 9:12 am
jerrymcdougal, it was just a suggestion in case you wanted that distance from the wall, using the end-fire cab. Putting it up at the ceiling would give you clearance on the floor for other things.
The "distance from the wall location" benefits can be best answered by Bill.
That is a smart idea, no doubt! Mounting would be the hardest bit.

Post Reply