It depends on how you’re measuring the subs, subs and midbass freqs are incredibly easy to get timed up with something with phase measurement... I cheat and use smaart and can get three subs timed to perfection in my car (two IB tens and a single 15 in a 3 cubic foot sealed enclosure...
You don’t use a set slope, you use the one that gives the best match, and also you tend to use more phase adjustment in adjusting subs at the same time as ta, distance doesn’t really matter as delay will compensate if it goes high enough
Open forum offer... I am U.K. based on the Nottinghamshire/midlands area, if anyone is localish and has a dsp (or a decent av amp with good adjustment) setup that wants subs and mains dialling in I would be open to going out and (for a tenner as it would have to be a paid job due to corona virus laws...) setting up and timing subs and mains to the listening position with my trusty smaart kit and I will put all graphs up on here for all to see so people have a better idea of what you are trying to do and why doing it by ear is a very laborious task with every combination of delay and frequency possible
This is not my job however I have used smaart extensively for timing subs/midbass/mids/tweeters in various vehicles with exceptional success
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Some thoughts:
I am only after one octave from 25Hz to 50Hz
I don't want to cross over higher than that as the same system is used for music and I'd like to keep the current response around the room
My target SPL is 80dB at the listening position (0.5m), so equivalent to 74dB @1m. 2 x 6 inch drivers would be plenty with cone excursion of 1.2mm at 25Hz
With a 3-seater sofa, I'm thinking the subs approximately between seats. At 50Hz, the wavelength is 6.8m, so the 0.6m difference in path length for the end seats is 32 degrees. This should be small enough to not worry about
Brian
I am only after one octave from 25Hz to 50Hz
I don't want to cross over higher than that as the same system is used for music and I'd like to keep the current response around the room
My target SPL is 80dB at the listening position (0.5m), so equivalent to 74dB @1m. 2 x 6 inch drivers would be plenty with cone excursion of 1.2mm at 25Hz
With a 3-seater sofa, I'm thinking the subs approximately between seats. At 50Hz, the wavelength is 6.8m, so the 0.6m difference in path length for the end seats is 32 degrees. This should be small enough to not worry about
Brian
So.... if I had an apartment I would do the BOSS back couch “”without a question”” every day of the week and twice tomorrow.
Why? Well it works great from 10hz all the way to 60hz IMO. And doesn’t create a huge amount of spl but gives all the fun.
How do I know this? Because I have one. Also, I have my minidsp setup so that my “night mode” will turn my subs off and only run my three way mains from 60hz and up and my BOSS couch from 60hz and down (again, NO SUBS ON). My wife who sleeps right above this room doesn’t mind at all (or doesn’t complain) when I watch movies late at night. BTW - during normal listening the couch only runs from 5-25hz and my subs from 19hz and up.
When I change programs via remote between night mode and normal listening I am actually quite surprised how similar they are, not exactly but then maybe try a simple small sub to help it along.
Just my $.02. Good luck.
Why? Well it works great from 10hz all the way to 60hz IMO. And doesn’t create a huge amount of spl but gives all the fun.
How do I know this? Because I have one. Also, I have my minidsp setup so that my “night mode” will turn my subs off and only run my three way mains from 60hz and up and my BOSS couch from 60hz and down (again, NO SUBS ON). My wife who sleeps right above this room doesn’t mind at all (or doesn’t complain) when I watch movies late at night. BTW - during normal listening the couch only runs from 5-25hz and my subs from 19hz and up.
When I change programs via remote between night mode and normal listening I am actually quite surprised how similar they are, not exactly but then maybe try a simple small sub to help it along.
Just my $.02. Good luck.
A shout out for the mini dsp. I use one for adjusting the subs, the latest REW software will allow you to align each sub, 1&2, the 1,2 &3 and so on, then you can see how they all work across the seating area, EQ (as a group or ideally as individual subs across the seating area, then together this will reduce over adjusting them as a group). You choose the alignment frequency which is usually near the crossover as the perfect setting will change with each seating position you are just choosing a compromise in any case. With the mini dsp you can roll off in the dsp or using the subs themselves if the have a roll off or a combination of both and see how they integrate. To check the alignment of the front to the subs you measure L,R from he MLP and then adjust the delay of the sub group which is now aligned. Then you can see what's going on across the seats with alignment too and tweak as required. You realise with bass it can change quite a bit over a few feet. But once you have the best compromise you can get very good overall results
I crossover at 50 for the mains and 60 for the rest.
I crossover at 50 for the mains and 60 for the rest.
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Thanks audiophile, I like it
I'm guessing that the bass from this wouldn't travel far as it would cancel round the back of the driver, so this would be ideal
How much power are you using for this? Being so close, it must be less than 1W
I thought this would be a yes/no answer, but got three good suggestions now
1, Sealed box (mine)
2, Butt shaker (Subw00er)
3, Boss back couch (audiophile56472)
Thanks everyone!
Brian
Brian, hi
Low ferequency bass in a domestic room will decay (bounce around and lose energy as it gets absorbed) this decay is much slower than high frequencies. Mainly because absorption at lower frequencies is much lower, the wavelength is much longer and it travel through thing much better.
In reality a sub at the back of the sofa will produce less db at the front wall than a sub at the front wall but dont think it will be substantially different. Unless you ar thinking of playing volumes very low and dont want to EQ and have an enormous sub horn you will need more than 1W !
Low ferequency bass in a domestic room will decay (bounce around and lose energy as it gets absorbed) this decay is much slower than high frequencies. Mainly because absorption at lower frequencies is much lower, the wavelength is much longer and it travel through thing much better.
In reality a sub at the back of the sofa will produce less db at the front wall than a sub at the front wall but dont think it will be substantially different. Unless you ar thinking of playing volumes very low and dont want to EQ and have an enormous sub horn you will need more than 1W !
Hi IWC,
All my calcs have been without EQ, and you are right - I will need more than this theoretical value
The front wall is about 4m away and the sub I'm planning would be 0.5m away. That's 1/8 of the distance (or the mains are 8 times as far away).
My target SPL at the listening position is 80dB
The mains would need to be at 92dB @ 1m
The sub would need to be at 74dB @ 1m
I don't know how much EQ I will need, but with +20dB I will only need 10W with an 84dB @ 1W speaker, so not too much
I'll have more for testing and get it measured when built
Brian
All my calcs have been without EQ, and you are right - I will need more than this theoretical value
The front wall is about 4m away and the sub I'm planning would be 0.5m away. That's 1/8 of the distance (or the mains are 8 times as far away).
My target SPL at the listening position is 80dB
The mains would need to be at 92dB @ 1m
The sub would need to be at 74dB @ 1m
I don't know how much EQ I will need, but with +20dB I will only need 10W with an 84dB @ 1W speaker, so not too much
I'll have more for testing and get it measured when built
Brian
Dynamic peaks may require quite a bit more power, most subs need a lot of cone damping and usually have transistor amps of a 100+ Watts
I play films at a reasonable level drive each speaker with 70W amps (135W into 4Ohms) and have three subs with 500W each, the sub dial is quite high on the sub to match in after EQ. To get near flat across a wide seating area that is not close to the back wall can mean adding some reasonable db cuts at room resonances. This is after time alignment and EQ for the three seating positions and average. The same subs played individually in the three seating positions which are quite a mess this is with the same EQ.....(this graph misses one sub in one position, hence only 8 curves, 3 subs, 3 positions)
I play films at a reasonable level drive each speaker with 70W amps (135W into 4Ohms) and have three subs with 500W each, the sub dial is quite high on the sub to match in after EQ. To get near flat across a wide seating area that is not close to the back wall can mean adding some reasonable db cuts at room resonances. This is after time alignment and EQ for the three seating positions and average. The same subs played individually in the three seating positions which are quite a mess this is with the same EQ.....(this graph misses one sub in one position, hence only 8 curves, 3 subs, 3 positions)
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