I just bought a second hand 18 Inch Sub. It is a closed box and uses the BMS 18N850.
Hypex FA251 is my amp. So I have three presets 100/90/80Hz low pass. But since I hear so much more bass than with my previous 15 Inch...I wanted to look at the crossover settings again. Maybe boost some freq so playing music with lower volume sounds a bit fuller?
I know these are all vague requirements. And perhaps there is no rule of thumb. And one should just play around with it and see what works in my room. etc.
It's just that I wonder what do other folks do that have an active sub with a dsp.
Hypex FA251 is my amp. So I have three presets 100/90/80Hz low pass. But since I hear so much more bass than with my previous 15 Inch...I wanted to look at the crossover settings again. Maybe boost some freq so playing music with lower volume sounds a bit fuller?
I know these are all vague requirements. And perhaps there is no rule of thumb. And one should just play around with it and see what works in my room. etc.
It's just that I wonder what do other folks do that have an active sub with a dsp.
"Is there a rule of thumb too boost a frequency in a sub" - it will help you gauge your performance, basically power and excursion are your limitations and it seems that with high powered woofers, you run out of excursion first, depending on how much power you need to give it... efficiency is created from large enclosures and sometimes the use of the rear wave of the driver, via bass reflex and trans mission line. never the less, those are your limitations, when you run of out one or the other undesirable things happen. Running out of excursions results in a large increase of distortion. So what ever frequency you want to be the lowest, the system cutoff if you will, what ever the lowest spl you can play at the note, sorta dictates everything else. The response can be built using EQ. Using a high pass, helps, but you have to be wise, you can cause ringing at the filter frequency if the response change is too dramatic. A high pass will protect the driver from lower more demanding signal, and allow you to have more clean headroom.
This is first going to be about placement.
I'd begin by setting it to the higher frequency, and moving it around the room until the mains and sub are not overwhelming each other with room modes. You'll be looking for general smoothness, rather than room mode peaks and particularly dips. It may not be flat in general yet, but that's OK.. Measure at varied locations since room agreement is a good sign.
Next, adjust levels and phase. It's usually better to overlap, rather than cross since this better evens your room.. however the crossover setting also happens to be one of the tools you'd use for altering phase, unless you can do that separately. Finally, use global EQ.
I'd begin by setting it to the higher frequency, and moving it around the room until the mains and sub are not overwhelming each other with room modes. You'll be looking for general smoothness, rather than room mode peaks and particularly dips. It may not be flat in general yet, but that's OK.. Measure at varied locations since room agreement is a good sign.
Next, adjust levels and phase. It's usually better to overlap, rather than cross since this better evens your room.. however the crossover setting also happens to be one of the tools you'd use for altering phase, unless you can do that separately. Finally, use global EQ.
Rick I think the OP is using this new sub as an adjunct to his OB speakers, although I could be wrong that's how I read the query.
There is a "RoT" for using a simple first order high pass to boost LF but it involves a small Qb = 1 sealed box but isn't that sort of manipulation built into the Hypex amps?? My own RoT is to boost 30Hz by 6dB but if I had that capability I'd be doing +6dB at 16Hz and listening
There is a "RoT" for using a simple first order high pass to boost LF but it involves a small Qb = 1 sealed box but isn't that sort of manipulation built into the Hypex amps?? My own RoT is to boost 30Hz by 6dB but if I had that capability I'd be doing +6dB at 16Hz and listening
I wish I had more useful advice, I would follow AllenB's advice, I have two subs and integrating them properly so that I am not reminded they are there when they really shouldn't be, and yet are fully there when there is music in their passbands proved a challenge.
I initially tried blending with overlap between the subs and woofers in order to tame some room modes. It worked much less well in my space than just crossing from the mains to the subs. I tried to place the subs in spots where REW indicated they would work reasonably well.
I use a lot of DSP as AllenB will confirm and it is a matter of measuring, listening, adjusting and then listening again. Go light on the EQ, I generally find that about half the EQ I think is needed from looking at response curves works best - it is very easy to overcorrect, but a small number of measurements scattered across the room do not tell the full story, err on the conservative side. Do not do this when you are tired or have listening fatigue!
I highpass at 10Hz and cross at 45Hz, and have stereo subs. I use an LR48 for the first cross which I found resulted in the best overall balance. (Onken bass bins) The rest are linear phase at 24dB/oct.
Good luck! Small steps!
I initially tried blending with overlap between the subs and woofers in order to tame some room modes. It worked much less well in my space than just crossing from the mains to the subs. I tried to place the subs in spots where REW indicated they would work reasonably well.
I use a lot of DSP as AllenB will confirm and it is a matter of measuring, listening, adjusting and then listening again. Go light on the EQ, I generally find that about half the EQ I think is needed from looking at response curves works best - it is very easy to overcorrect, but a small number of measurements scattered across the room do not tell the full story, err on the conservative side. Do not do this when you are tired or have listening fatigue!
I highpass at 10Hz and cross at 45Hz, and have stereo subs. I use an LR48 for the first cross which I found resulted in the best overall balance. (Onken bass bins) The rest are linear phase at 24dB/oct.
Good luck! Small steps!
Closed box 18 inch sub mentioned right in the first line of the first post.
Wise counsel.
Subs have to work together across space, in contrast to regular crossover terms. Multiple subs both boost and cut, being also active bass absorbers, all working towards a middle-ground.
To boost bass or flatten lower response
Use a low pass shelving filter.
Centered around 45 to 55 Hz , 50 Hz being somewhat "generic"
Depends on your measured response.
But a generic starting point is the filter center at 45 to 55 Hz
And assuming around 6 dB of losses.
Depending on listening preference or SPL levels
Be using 5 to 8 dB of Gain
Of course its known that at low listening levels more bass boost is preferred.
around 8 dB
And at higher listening levels less bass boost is preferred.
around 4 dB
Hence the 80's receivers with adjustable contour
for loudness maximisers. And when used correctly to
adjust listening levels. The low pass shelving filter
gain boost was automatically adjusted for low or high listening
levels.
Far as a live audio 18" bass drops pretty quick.
I would just try corner loading before boosting.
To not get the upper dip cancel many get in the room.
Woofer stays low to the ground in the corner.
AKA in the corner, on its back
woofer firing straight up.
Use a low pass shelving filter.
Centered around 45 to 55 Hz , 50 Hz being somewhat "generic"
Depends on your measured response.
But a generic starting point is the filter center at 45 to 55 Hz
And assuming around 6 dB of losses.
Depending on listening preference or SPL levels
Be using 5 to 8 dB of Gain
Of course its known that at low listening levels more bass boost is preferred.
around 8 dB
And at higher listening levels less bass boost is preferred.
around 4 dB
Hence the 80's receivers with adjustable contour
for loudness maximisers. And when used correctly to
adjust listening levels. The low pass shelving filter
gain boost was automatically adjusted for low or high listening
levels.
Far as a live audio 18" bass drops pretty quick.
I would just try corner loading before boosting.
To not get the upper dip cancel many get in the room.
Woofer stays low to the ground in the corner.
AKA in the corner, on its back
woofer firing straight up.
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Thanks for all the input!
I have no "real" issues btw. These subs I have now are fantastic! I am as happy as a pig in ****. Previously I had a closed sub 15 Eminence Delta 15 LFA. in a small closed box. Facing each other because of the way I built it. And it was fine. But not as tight and present as I wanted it to be.
I just bought these diy subs yesterday and they are front facing. I'm suprised I even had to lower the volume button. Not even 9 o clock. Here a picture of one side.. I was just curious about a boost setting...sort of as a "loudness" button during lower volumes. But I might start looking for a measuring setup to get rid of guesswork.
I have no "real" issues btw. These subs I have now are fantastic! I am as happy as a pig in ****. Previously I had a closed sub 15 Eminence Delta 15 LFA. in a small closed box. Facing each other because of the way I built it. And it was fine. But not as tight and present as I wanted it to be.
I just bought these diy subs yesterday and they are front facing. I'm suprised I even had to lower the volume button. Not even 9 o clock. Here a picture of one side.. I was just curious about a boost setting...sort of as a "loudness" button during lower volumes. But I might start looking for a measuring setup to get rid of guesswork.
Buy a DSP-LF from Amazon and you can tune it to your requiements. I use one and it's much better than using the amps sub output.
https://www.amazon.co.uk/Dayton-Audio-DSP-LF-Frequency-Controller/dp/B085KXPXSN/ref=sr_1_1
@batteryman: I have an ipad. Would that work? Sounds like just the thing. I could utilize my MyRef amp which is gathering dust. That said..pretty happy after the advice I got in this thread.
The manual is on their website: https://www.daytonaudio.com/product/1664/dsp-lf-low-frequency-dsp-controller
It says iOS devices so guess it should work,
It says iOS devices so guess it should work,