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Jone5y

Is a sub at the rear better than none at all

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17 hours ago, Cloth Ears said:

Not sure what your budget is, but the cavity on the left looks tailor made for a reasonable ported sub. 

 

I'm guessing it's about 600-odd litres

I'd be looking to come in at around $1500 for driver, box and amp (or as close to that as possible)
The space is around 500l. 1000x700x800

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1 hour ago, Jone5y said:

I'd be looking to come in at around $1500 for driver, box and amp (or as close to that as possible)
The space is around 500l. 1000x700x800

Look, I'm no expert. I build using an old spreadsheet called Unibox. Quickly running a Dayton Audio UM18-22 through that shows you could use it as a...

  1. Sealed box (about 400litres) with a really solid baffle and you could use that probably without any EQ with a big amplifier (1000W). As this would be driving it to about its limits, you probably wouldn't want to boost below 25Hz, if you did want EQ - but you could always balance it a bit by dropping above 25Hz by 3-6dB. Only after you've listened to it first, of course.
  2. Ported box. Possibly not super musical, but definitely worth it for movies. It would basically be a "Marty Cube" thing, with an 'L' shaped slot-port of about 105cm length, full width (on the floor) and about 6cm high. This would be able to be quite loud (well over 110dB at 15Hz and no issues with the driver excursion) and reasonably balanced.

Here's a UM18-22 thread from AVS forum: https://www.avsforum.com/threads/um18-fully-marty-build.2936768/#post-55206500. Yours would look similar to the first model (on the inside), but you wouldn't need bracing as your 'box' is made of bricks and concrete. The port would not be as long, it would need the 'L', but only about 25cm of the upward pipe (as I've assumed that your 800mm was the front to back dimension). I'd also suggest some sort of cradle to rest the magnet on...

 

16 hours ago, Red Spade Audio said:

There's always some risk of localisation with a single sub at the back of the room. Simply having a 4th order crossover at 80 Hz won't necessarily avoid the problem.

Based on experience, I've found it quite easy to find 80Hz (even if it's down 3-6dB - like with a 4th order crossover). So I would look at 50-60Hz as being the highest I'd like to crossover to a sub unless the crossover is 8th order (and I've never used one of those). Since I moved my bass boxes under my main speakers, there is no issue. And the subwoofer I'm building now will be only used with a 50 or 35Hz low-pass (depending on the crossover I decide on).

Edited by Cloth Ears

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13 hours ago, Jone5y said:

Hi @Red Spade Audio 

I fought hard for a sub at the front and, prior to the reno, had an old magazine storage box already up the front that would've done nicely. Alas, it is gone now and any additional speakers will not be permitted . Truth be told the current floorstanders would be gone if the boss had her way. The coffee table idea is a good one but the chosen design for the new table is not enclosed and therefore not an option.  Can't think of a way to incorporate IB. The front wall of the room leads to the exterior, as do the side walls and there is no ceiling space to work with. There is a garage under the floor which would be ideal but a driver mounted in the fresh carpet is unlikely to get the nod.

 

What would i be looking for in the measurements and how would the setup work? Play a tone through the speaker in the listening position and assess the various mic positions for ....?

 

If i could wrangle a sub into the cavity on the other side of the room as well, would that potentially lead to a better result?

"Darling, I promise you, there always was a giant return air duct in this corner! What do you think? That I just added a useless air duct in the corner for no good reason?!"

If the matter goes to the high court of interior design, I had nothing to do with it!

There is a mix of things you can look for, including bottom end extension, avoiding major dips, flattest overall response, highest output. The emphasis changes as you change the number of subs and also the number of listening positions you want to optimise.

For one sub and one seat, the answer is often relatively straightforward. It's mostly about avoiding dips, as you can EQ out the peaks very well in that one position. As you start adding more seats you want to optimise, especially in more than one row and also as you start to consider more subs, the exercise becomes more complex. The answer leans more towards reducing seat to seat variation.

 

 

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Appreciate your input Cloth Ears, i did enjoy playing around with simulations a couple of years ago.  When funds allow I'll probably start a thread specific to the design of the sub

 

Everything will be optimised for 1 seating position, potentially 2 - immediately adjacent to each other. Not entertaining the idea of multiple rows

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47 minutes ago, Jone5y said:

Appreciate your input Cloth Ears, i did enjoy playing around with simulations a couple of years ago.  When funds allow I'll probably start a thread specific to the design of the sub

 

Everything will be optimised for 1 seating position, potentially 2 - immediately adjacent to each other. Not entertaining the idea of multiple rows

NP. I was surprised how well the single UM 18-22 simulated. And for $699 (Aussie) I thought  that was pretty good. Especially considering it can move more than 2 litres of air at a time (3 times the amount it's cheaper cousin can do. If I didn't already have a pair of drivers, I might try to get one of those!

 

Looking forward to the build thread!

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Another option is a near field dipole (open baffle) subwoofer. It's light and easy to move. You bring it out of hiding and plonk it 1m in front of you when you are listening and put away when you're finished (or when she sees it)

 

The other bonus is you can listen late at night because its near field and dipole and does not really "leak" in to other part of the house

 

Also being dipole, you don't have to really worry about room mode issues. It sounds VERY clean.

 

I have one and I love it. Will never use boxed subs again BUT its not for everyone I guess

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1 hour ago, logarhythm said:

Another option is a near field dipole (open baffle) subwoofer. It's light and easy to move. You bring it out of hiding and plonk it 1m in front of you when you are listening and put away when you're finished (or when she sees it)

 

The other bonus is you can listen late at night because its near field and dipole and does not really "leak" in to other part of the house

 

Also being dipole, you don't have to really worry about room mode issues. It sounds VERY clean.

 

I have one and I love it. Will never use boxed subs again BUT its not for everyone I guess

For the size of the room (well over 200 m3) it would have to a pretty big OB to provide any sort of bass response in the room. Four to six large drivers, maybe in 'H' or 'S' enclosures might work. But I think it might blow the budget.

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Just now, Cloth Ears said:

For the size of the room (well over 200 m3) it would have to a pretty big OB to provide any sort of bass response in the room. Four to six large drivers, maybe in 'H' or 'S' enclosures might work. But I think it might blow the budget.

Size of room is not relevant if it is nearfield :) 

 

I have one 18” in small H frame and at the volume I listen it is more than enough but it really depends on what SPL and cutoff frequency you are chasing

 

cheers 

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14 hours ago, logarhythm said:

Size of room is not relevant if it is nearfield :)

 

I can't argue with that.

 

But it's not much good for a home theatre...

 

13 hours ago, danrey said:

How about an entertainment unit in tasmanian blackwood with concealed sub like the Vaf Platform 2? 

 

https://vaf.com.au/collections/subwoofers/products/platform-subwoofer?variant=19932601477

 

 

Very pretty! There might be vibration issues unless the woofers were mounted opposing each other at the ends of the unit. "WOW! The whole room seemed to vibrate when the T-Rex put his foot down!" 😁

Edited by Cloth Ears

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5 hours ago, Cloth Ears said:

"WOW! The whole room seemed to vibrate when the T-Rex put his foot down!" 😁

 

"Yeah, new thicker speaker cables did the trick"

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On 15/09/2020 at 7:11 PM, danrey said:

How about an entertainment unit in tasmanian blackwood with concealed sub like the Vaf Platform 2? 

 

https://vaf.com.au/collections/subwoofers/products/platform-subwoofer?variant=19932601477

 

 

Stunning. Would also match the decor as I've laid stringy bark floors in other rooms and the lounge has some stringy in it at the back.  

I actually had something like this in mind at the start, but as a coffee table. the boss didn't want components sitting on top of the ent unit. So I'm in the process of wrapping a couple of ikea carcasses in stringy and decorative moulding. The new coffee table design has been decided and unfortunately it is of an open design 😒

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