Sub Success!

[oldius]

All points noted.

 

[MF 1000]

My own use of subs ...well I now don't regard them as subs really as my pair of Volt 18 " drivers in 140 litre cabs operate from 15 Hz to 200 Hz - more like full range bass  speakers.  Those who have listened to them in my lounge have said you don't know they are there other than the bass is available across the full range of frequencies.

Its taken me a year to get them fully integrated into the system and an upgrade from  one 500 watt amp feeding both of them to twin bridged 750 watt monos at present. 

 

[MartinC]

I am not alluding to anything I sell, everyone’s opinion is formed from their experience, Martin expressed concern about reflections, and the speakers he uses have a very ragged off-axis response , With those speakers you would have to pay attention to first reflections.

My comments earlier in this thread apply to absolutely every loudspeaker on the planet, not just mine. I was commenting on basic acoustics.

 

[MartinC]

Forgive me if I've missed it but I don't think this has been mentioned yet...

One important point if applying crossover filters is that these will be additive to the natural roll-off of the main speakers. It may seem 'obvious' that you set low and high-pass filters at the same frequency and the same roll-off (e.g. both 24 dB/octave at 80 Hz) but if there is any natural roll-off of the main speaker over the frequency range that the high-pass filter is rolling off then the actual roll-off that you end up with will be steeper. When combined with the sub output this could result in an unintended dip in the frequency response.

One way to avoid the above issue is to use a relatively steep crossover filter at a frequency well above where the output of the main speakers rolls off, which is what I've ended up doing (although not primarily for this reason). Another is to compensate for any dip in the combined sub + mains result with EQ, which I suspect is what @Camverton has done with his tests of 4 different crossover points combined with Dirac Live. (Do correct me if I'm wrong @Camverton.)

Beyond this it gets more complicated but broadly you'd want to be experimenting with a slower roll-off on the high-pass filter than the low-pass filter (if possible) and/or a high-pass filter frequency that is a bit lower than that of the low-pass filter.

It's important to bear this complication in mind when comparing how you think a system performs with different crossover frequencies, as doing this properly is more complicated than just changing the set frequency of the low and high-pass filters.

Finally I'll just add that all aspects of trying to integrate a subwoofer well are made a lot easier if someone is prepared to buy a suitable microphone and take the time to learn how make use of it. 

 

[Pedro2]

Forgive me if I've missed it but I don't think this has been mentioned yet...

One important point if applying crossover filters is that these will be additive to the natural roll-off of the main speakers. It may seem 'obvious' that you set low and high-pass filters at the same frequency and the same roll-off (e.g. both 24 dB/octave at 80 Hz) but if there is any natural roll-off of the main speaker over the frequency range that the high-pass filter is rolling off then the actual roll-off that you end up with will be steeper. When combined with the sub output this could result in an unintended dip in the frequency response.

One way to avoid the above issue is to use a relatively steep crossover filter at a frequency well above where the output of the main speakers rolls off, which is what I've ended up doing (although not primarily for this reason). Another is to compensate for any dip in the combined sub + mains result with EQ, which I suspect is what @Camverton has done with his tests of 4 different crossover points combined with Dirac Live. (Do correct me if I'm wrong @Camverton.)

Beyond this it gets more complicated but broadly you'd want to be experimenting with a slower roll-off on the high-pass filter than the low-pass filter (if possible) and/or a high-pass filter frequency that is a bit lower than that of the low-pass filter.

It's important to bear this complication in mind when comparing how you think a system performs with different crossover frequencies, as doing this properly is more complicated than just changing the set frequency of the low and high-pass filters.

Finally I'll just add that all aspects of trying to integrate a subwoofer well are made a lot easier if someone is prepared to buy a suitable microphone and take the time to learn how make use of it. 

Thanks Martinc,

Yet more useful advice and suggestions. The filter on the dbx is adjustable between 45hz and 960hz with a switch that allows for x10 instead (450 to 9600). I will therefore try some higher settings (only gone up to 95hz so far) with my set up.

One thing that I have discovered so far is that there are many variables to play with. This makes it fun for some but it won’t be to everyone’s liking. I’m pretty sure that adding a sub is not ‘plug and play’ but that some investment in time can pay real dividends. I might even get a microphone!

 

[MartinC]

One thing that I have discovered so far is that there are many variables to play with. This makes it fun for some but it won’t be to everyone’s liking. I’m pretty sure that adding a sub is not ‘plug and play’ but that some investment in time can pay real dividends.

Definitely. There is plenty of scope to add a subwoofer and make a system sound worse if not done well.

If you decide to buy a microphone I'd suggest you keep things simple and buy a miniDSP UMIK-1. There are potentially slightly cheaper options but this is the most widely used and you'd be more sure it would do exactly what you want without issues.

 

[Camverton]

No reference was made to any product being sold.

Thank you for comments, and apologies for disrupting the subject of the thread. I used the word “allude” as there was no reference to a product by name so much as by type. This was the comment I was referring to “The best option would be modern loudspeakers with boundary filters ( filters which adjust bass output according to position)”. A clear reference to a type of speaker he sells. As an isolated example it matters not a jot but it is part of a trend that is causing discord and disruption in numerous threads. Imagine what would the forum would be like if all dealers did this. Thankfully most dealers seem to stick to their area of the forum where folk can seek out their views knowing where they are coming from.

Back to the subject in hand (at last I hear everyone cry  ). Yes I agree it is far better to have main speakers that not only cover the bass frequencies but in a way that conveys a realist sense of scale. For me and my particular choice of speaker that would involve spending close on £50k with trade in! So sub it has to be.
 

Enjoyable results can be achieved fairly easily but really good integration takes a lot of time and probably more expertise than I’ll ever have! I use  miniDSP SHD, careful positioning of speakers, matching levels and delays, tweaking crossover points and slopes and then applying Dirac for final optimisation. Quite a procedure and involving a lot of listening and checking with REW, which in itself takes ordinary people a fair old time to learn to use effectively. 
 

Is it all worth it? For me yes but I can understand why many wouldn’t want to bother. I still think a bigger pair of mains would be better though, if only they weren’t so darn expensive. I have tried lower priced alternatives in the last year but only Quads were of a comparable overall sound quality and even then I still find the need for a sub with them.

 

[oldius]

Thank you for comments, and apologies for disrupting the subject of the thread. I used the word “allude” as there was no reference to a product by name so much as by type. This was the comment I was referring to “The best option would be modern loudspeakers with boundary filters ( filters which adjust bass output according to position)”. A clear reference to a type of speaker he sells. As an isolated example it matters not a jot but it is part of a trend that is causing discord and disruption in numerous threads. Imagine what would the forum would be like if all dealers did this. Thankfully most dealers seem to stick to their area of the forum where folk can seek out their views knowing where they are coming from.

Back to the subject in hand (at last I hear everyone cry  ). Yes I agree it is far better to have main speakers that not only cover the bass frequencies but in a way that conveys a realist sense of scale. For me and my particular choice of speaker that would involve spending close on £50k with trade in! So sub it has to be.
 

Enjoyable results can be achieved fairly easily but really good integration takes a lot of time and probably more expertise than I’ll ever have! I use  miniDSP SHD, careful positioning of speakers, matching levels and delays, tweaking crossover points and slopes and then applying Dirac for final optimisation. Quite a procedure and involving a lot of listening and checking with REW, which in itself takes ordinary people a fair old time to learn to use effectively. 
 

Is it all worth it? For me yes but I can understand why many wouldn’t want to bother. I still think a bigger pair of mains would be better though, if only they weren’t so darn expensive. I have tried lower priced alternatives in the last year but only Quads were of a comparable overall sound quality and even then I still find the need for a sub with them.

You are right, of course, which is why I commented that it was reasonable to assume that dealers would believe in the products they sell as a means to improving sound quality; I would certainly hope that my dealer would. It is unfortunate, but natural, to assume then that when a dealer recommends a solution to a problem raised, they are using it to sell product. I am sure that is the case sometimes but I don't to presume guilt as a default.

As usual, I think that most people operate with the best of intentions here, but sometimes tone can be questionable. It is why Rabski and I intervened in another thread; we just need to think before we post sometimes. 

As I said earlier, I am always available by PM and will listen to views. If a post is considered to be offensive then it can be reported by the person it is directed to, then the moderators will view it and discuss it together, often hiding it until processed.

Thanks for your input.

 

[MartinC]

I'm actually not at all convinced that bigger main speakers would be better. I certainly think there is an advantage to being able to place a sub or subs optimally for bass performance whilst the main speaker positions can be more conventional.

I definitely agree that the subwoofer route is cheaper than very large high quality floorstanding speakers.

 

[oldius]

I'm actually not at all convinced that bigger main speakers would be better. I certainly think there is an advantage to being able to place a sub or subs optimally for bass performance whilst the main speaker positions can be more conventional.

I definitely agree that the subwoofer route is cheaper than very large high quality floorstanding speakers.

So much depends on the room that it is impossible to 'predict' best solutions. 

 

[PuritéAudio]

Thank you for comments, and apologies for disrupting the subject of the thread. I used the word “allude” as there was no reference to a product by name so much as by type. This was the comment I was referring to “The best option would be modern loudspeakers with boundary filters ( filters which adjust bass output according to position)”. A clear reference to a type of speaker he sells. As an isolated example it matters not a jot but it is part of a trend that is causing discord and disruption in numerous threads. Imagine what would the forum would be like if all dealers did this. Thankfully most dealers seem to stick to their area of the forum where folk can seek out their views knowing where they are coming from.

Back to the subject in hand (at last I hear everyone cry  ). Yes I agree it is far better to have main speakers that not only cover the bass frequencies but in a way that conveys a realist sense of scale. For me and my particular choice of speaker that would involve spending close on £50k with trade in! So sub it has to be.
 

Enjoyable results can be achieved fairly easily but really good integration takes a lot of time and probably more expertise than I’ll ever have! I use  miniDSP SHD, careful positioning of speakers, matching levels and delays, tweaking crossover points and slopes and then applying Dirac for final optimisation. Quite a procedure and involving a lot of listening and checking with REW, which in itself takes ordinary people a fair old time to learn to use effectively. 
 

Is it all worth it? For me yes but I can understand why many wouldn’t want to bother. I still think a bigger pair of mains would be better though, if only they weren’t so darn expensive. I have tried lower priced alternatives in the last year but only Quads were of a comparable overall sound quality and even then I still find the need for a sub with them.

Malcolm, every contemporary monitor has boundary adjustment and quite a number of domestic loudspeakers, I believe that even your own loudspeakers have boundary filtering.

Keith

 

[Camverton]

I'm actually not at all convinced that bigger main speakers would be better. I certainly think there is an advantage to being able to place a sub or subs optimally for bass performance whilst the main speaker positions can be more conventional.

I definitely agree that the subwoofer route is cheaper than very large high quality floorstanding speakers.

Perhaps it depends on the particular brand and type of speaker. I was thinking of my entry level MBLs compared to their midrange model and their second from the top of which I am quite desirous! Thinking of my Meridian dsp5500 which is big and blousy I think it does a sense of scale well but at the expense of the refinement of their smaller speakers, so in that case You are probably right; a smaller model with a sub. Come to think of it I prefer the four panel Quads to the six panel Quads so you might be right! 

Of course, such comparisons do come down to the skill in deployed in integrating the sub.

 

[Camverton]

Malcolm, every contemporary monitor has boundary adjustment and quite a number of domestic loudspeakers, I believe that even your own loudspeakers have boundary filtering.

Keith

Nope, of the three pairs of speakers I am using at the moment all are passive and none have boundary adjustment other than physically moving them. I do have, stored away, a pair of elderly active Meridian dsp5500 which include rudimentary boundary and corner settings but employing those settings was never very useful in my setups. None of the other speakers I have tucked away  :$  have any form of boundary adjustment.

 

[MotherSky]

Lots to consider picking through this thread - thank you @MartinC and @Camverton for your thoughts/experience - it took me no time at all to establish that port bungs are not an option with my speakers, but it did get me thinking: I much prefer the concept of room treatment to what I have now read concerning the DSP approach - as a starting point, is there any mileage in some form of panel on the wall behind the speakers? I'm assuming that it is the (rear firing) ports on the Proacs that are the main issue  - does anyone have a link to a decent article on room treatment for dummies? It's already a well damped room, and is a very irregular shape which seems to be beneficial, but I've never previously felt the need to look in detail at the acoustics - the measuring/microphone approach, whilst completely logical, does look like a hefty pain in the bits...

 

[MartinC]

as a starting point, is there any mileage in some form of panel on the wall behind the speakers?

Short answer - no. In that to be effective they'd need to be so thick as to preclude the near-wall speaker position I'm guessing you're looking to achieve? Also note that the low frequency sound from a port will radiate fairly equally in all directions, not just straight out towards the wall.

 

[Camverton]

Lots to consider picking through this thread - thank you @MartinC and @Camverton for your thoughts/experience - it took me no time at all to establish that port bungs are not an option with my speakers, but it did get me thinking: I much prefer the concept of room treatment to what I have now read concerning the DSP approach - as a starting point, is there any mileage in some form of panel on the wall behind the speakers? I'm assuming that it is the (rear firing) ports on the Proacs that are the main issue  - does anyone have a link to a decent article on room treatment for dummies? It's already a well damped room, and is a very irregular shape which seems to be beneficial, but I've never previously felt the need to look in detail at the acoustics - the measuring/microphone approach, whilst completely logical, does look like a hefty pain in the bits...

I have no experience of acoustic damping panels other than filling a room with carpets, books, and very heavy curtains. They may help a Little bit with bass but is of most use in controlling secondary reflections further up the frequency range. Having moved from a house with a smallish room to one with a much larger but more lively room I think I am a fan of “natural” damping. Curiously, in the old room I had to slope the bass up much more than in my current room to get the same sort of bass sound as measured in REW. To get the final balance for my wonky ears I use a few particular tracks where the bass is very a very low pulse and have the bass level such that it is an underlying subtle, pulse rather than a boom (Gavin Bryar’s Double bass concerto with Charlie Haden is very useful as is a lot of music by Philip Glass, he being very fond of a very deep underlying pulse).

I started using DSP in earnest with Meridian G68 pre/processor which incorporated Meridian Room Correction. It was pretty effective but not as versatile or effective as Dirac applied after careful integration. I suppose I find the idea of room EQ easier than installing acoustic panels, and apart from anything else you probably end up seeing acoustic panels, whereas you don’t see EQ. To do EQ well does take quite a lot of research and time and isn’t just a case of downloading REW. I certainly wouldn’t blame anyone for not wanting to go down that route, but it’s quite fun if you have an interest in that side of audio. One thing, I feel, is for sure and that is that one still has to do a lot of careful listening; as Martin said upthread it is easy to muck the sound up!