Sub woofers - sublime or ridiculous?

[Bill Fitzmaurice]

2 hours ago, paulbuzz said:

I took a different message from the article Bill, which I found interesting rather than reactionary. I felt that the author's main gripe was that following the widespread availability and installation of super-powerful subs in mainstream venues, the freshly-discovered option of creating very low frequencies at very high levels has encouraged sound-people to do just that, regardless of whether it's appropriate or not.

The article is titled A Case Against Subwoofers. Don't blame the subs for the actions of those who abuse them. This quote in particular tells me the author isn't well versed in gear: "If certified low-end experts like O’Malley and Carlson don’t use subwoofers to listen to music, why does anyone?" If I didn't use the subwoofer in my home or car systems when listening to music there wouldn't be anything to hear below 100Hz. He doesn't know diddly about recording studios either. The use of subs didn't end with Pretzel Logic. They're standard issue, and have been for forty years. And he's off with what he says about vinyl. Records do have narrow grooves, to prevent needle jump, and for that reason their bass content is rolled off. That rolloff is compensated for by the RIAA equalization of phono pre-amps. Needle jumping during payback from high bass content can happen, but not when the turntable is adequately isolated. 

 

[Phil Starr]

On 03/04/2019 at 19:24, chris_b said:

I believe this cab had a reputation for being woolly and boomy (ref Talkbass)

It would do, the sound of bass guitar doesn't usually have those frequencies and when it does they often excite room resonances. Bass sounds cleaner and clearer without those problems which is why HPF's clean up the sound and why subs aren't a good idea for bass.

On 03/04/2019 at 20:12, itu said:

Quite interesting, that the max SPL is only 124 dB and 121 dB @ 33 Hz. Not overly loud.

This relates to pretty low sensitivity and 600 W power handling capacity. To get something like 130 dB @ 33 Hz, the power handling should be close to 5 kW. The amp should be able to produce that power, too.

The sensitivity is 96dB so they've simply done a mathematical calculation of the level at 600W. roughly an extra 28dB. A lot of modern PA speakers ( maybe all of them) though are using very different figures for peak output. If you look at that QSC for example they quote the amplifier as '2000W peak'  with a 12" driver it is unlikely the speaker can handle more than 300W, either due to heat dissipation or more problematically excursion. If that speaker is 96dB/W too then they are probably claiming it outputs 129dB 96dB@ 1W so 129 @ 2000W In practice it will probably handle half the power the Ampeg can and thus will be 3dB down on the Ampeg. I'd also suspect that a lot of the figures are based upon some room reinforcement from the floor and possibly walls.

You make a good point about the sensitivity of the Ampeg though, it is very low for a 4x10. Not their usual fare. If you modify the drivers for low bass it means adding mass to the cone and using longer coils to cope with excursion at low frequencies. 

[Al Krow]

Digging up an old thread...

 

We did, in the end, invest in a sub (RCF 702 ASii) shortly before Covid hit us, but haven't taken it out in anger since getting. Almost got rolled out for a corporate charity event on Thurs but the hired sound crew, having initially said they would charge £2,000 to mic up our drum kit(!!!) - in the end asked us to use their sound system rather than our own PA, so it stayed in the back of my car for the gig. I A/B'd the PA with and without the sub beforehand and, no question, it's making for a much bigger low end than with just our two RCF 310A tops. I've got the crossover set at 110Hz rather than 80Hz - dunno if that is mostly what other folk are doing?

 

Those of you who have not gone down the IEM route, are any of you using the sub as backline to give you enough of the sound / feel of the bass line to avoid needing to take your rig for on stage monitoring or needing to put the bass through the floor monitors to hear yourself? Our preference would be to leave our single on stage monitor for the vocals. It's obviously not much fun playing a gig where you're struggling to hear yourself, but if we can cut down on the total amount of gear we need to take that would definitely be welcome!

 

Or would sticking the sub at the back behind the mics just lead to a wall of low end feedback-boominess?

 

Edited December 4, 2021 by Al Krow

[Jack]

Pleased the sub is treating you well.

 

1 hour ago, Al Krow said:

I've got the crossover set at 110Hz rather than 80Hz - dunno if that is mostly what other folk are doing?

 

In one band we've got too much sub for the tops so we've got it at 120Hz to take up the slack. In my other band we're running the manufacturers recommended rig and so they're set to 80Hz, again as recommended. Both are occasionally subject to change in difficult rooms.

[Bill Fitzmaurice]

At what frequency to cross over to the subs depends on how low the tops go before dropping off in response and/or output capability. Finding out where that frequency is usually requires experimentation, as it's not a spec provided by most PA manufacturers. 'What other folk are doing' should not be a consideration.

[Al Krow]

8 minutes ago, Bill Fitzmaurice said:

At what frequency to cross over to the subs depends on how low the tops go before dropping off in response and/or output capability. Finding out where that frequency is usually requires experimentation, as it's not a spec provided by most PA manufacturers. 'What other folk are doing' should not be a consideration.

Kinda get where you're coming from. However isn't there a more general point that if you're leaving the tops to focus on everything above 110Hz vs 80Hz, given that the sub(s) can handle everything below 110Hz, then that frees the tops up just a bit more, which is a big chunk of the purpose of the set up in the first place? And I wouldn't have thought you'd generally want the sub(s) to be going below 30Hz in any event?

 

Happy to be corrected on both points, if they don't make sense.

[Bill Fitzmaurice]

Crossing above 80Hz is usually the better option with all but high end PA, as typical portable PA tops don't go much below 100Hz, if at all. There's no reason for subs to go below even 35Hz with music. Below 30Hz is home theater territory.

[Bunion]

I used an SWR Goliath 410/Big Ben 118 combo years ago with an Ampeg SVT II Pro in a pub, Tiny PA for vocals  I was told the bass lines on one gig nearly made one girl puke. 
I was oblivious to this at the time but I was  quite chuffed when I was told after. 
Different times…
 

[Bill Fitzmaurice]

Maybe she preferred Entwhistle? Or Sir Paul? 🙄

[W1_Pro]

I play in a skiffle band occasionally, I double up on uke and microbass. I have a schertler combo which sits on one of those thoman 'The box' 12" powered subs which I dial in on the aux send of the microbass channel.  Works a treat as it goes...

[jazzyvee]

I have a Schertler Unico that I bought for my EUB and recently got a Barefaced LF800 powered sub to use via the schertler's aux send. It has an LF switch to set the crossover with it. I was not looking for a loud sub, just something to add some weight to the bottom end. So far I've used it on one outdoor under cover gig and it was fine. I have an indoor gig on Wednesday and if the sound guy wants it off. I will go along with that.👍

[Al Krow]

16 hours ago, W1_Pro said:

I play in a skiffle band occasionally, I double up on uke and microbass. I have a schertler combo which sits on one of those thoman 'The box' 12" powered subs which I dial in on the aux send of the microbass channel.  Works a treat as it goes...

 

26 minutes ago, jazzyvee said:

I have a Schertler Unico that I bought for my EUB and recently got a Barefaced LF800 powered sub to use via the schertler's aux send. It has an LF switch to set the crossover with it. I was not looking for a loud sub, just something to add some weight to the bottom end. So far I've used it on one outdoor under cover gig and it was fine. I have an indoor gig on Wednesday and if the sound guy wants it off. I will go along with that.👍

 

Useful suggestions gents. I'm sure the BF LF800 will deliver all the bottom end you need. @W1_Prowhich Thomann model did you go for? The CL 112 Sub is rated at 120W RMS going up to 1000W RMS for the Pyrit 212 SubA but looks great value at £525 including VAT. 41kg is going to much for my aging back, though!

 

I'm not sure what folk would reckon is a decent min with a full rock band? My RCF 702 AS ii delivers 700W RMS and is a more manageable 17.5kg / 39lbs which seems to be a decent power / weight compromise for our needs.

 

Edited December 6, 2021 by Al Krow

[W1_Pro]

So I got this one Al: https://www.thomann.de/gb/the_box_pyrit_112_sub_a.htm

It is the Pyrit one- I got it becuase it seemed a bit more 'pro' than the other models.

Its 24 kilos, but its not big, so quite manageable to lug about I find.  As Jazzyvee says, just adds a bit of weight to the bottom end.

 

 

[Al Krow]

1 hour ago, W1_Pro said:

So I got this one Al: https://www.thomann.de/gb/the_box_pyrit_112_sub_a.htm

It is the Pyrit one- I got it becuase it seemed a bit more 'pro' than the other models.

Its 24 kilos, but its not big, so quite manageable to lug about I find.  As Jazzyvee says, just adds a bit of weight to the bottom end.

Yup, that does look good! And great value too (half the price of my RCF)!

[Chienmortbb]

On 28/02/2019 at 20:35, skidder652003 said:

we have 2 x 15 active RCF's and 1 x Mackie sub, everything is mic'd to FOH,  but only the Kick, Toms and Bass through the Sub with high pass filter. The bass is turned way down through the sub, with the emphasis on the kick for that thud in the chest without mud. So IMO deffo no sub for backline, strictly FOH, but possibly not necessary for quality 15" PA Tops and a good quality Bass Backline, especially if we're talking Dog n Duck territory.

PS Mackie subs are terrible, should have gone for another RCF

Mackie Tops are also far from ideal. To be fair I am talking about the Thump series and I have not come across a more overated (power wise) or poorly designed product,  but then I don't get out much.

Edited December 7, 2021 by Chienmortbb

[Al Krow]

In relation in to my second question a few days back...

On 04/12/2021 at 15:20, Al Krow said:

Those of you who have not gone down the IEM route, are any of you using the sub as backline to give you enough of the sound / feel of the bass line to avoid needing to take your rig for on stage monitoring or needing to put the bass through the floor monitors to hear yourself? Our preference would be to leave our single on stage monitor for the vocals. It's obviously not much fun playing a gig where you're struggling to hear yourself, but if we can cut down on the total amount of gear we need to take that would definitely be welcome!

Or would sticking the sub at the back behind the mics just lead to a wall of low end feedback-boominess?

 

I've spotted that Phil had already provided an answer to this a couple of years back, in his excellent post, at the start of this thread:

On 01/03/2019 at 08:20, Phil Starr said:

...You really don't want deep bass on stage, or in the rehearsal room. If it is loud enough to reach the audience then it is going to be a real nuisance for the band, and of course if the audience can't hear it why would you do it? If you want it in your rig for personal practice then fill your boots, it might be fun and it's only you that's affected. We've probably all tried it out if we have the PA sitting around at home

The problem is two fold. every extra sound you add into the stage mix makes it harder for all the band to distinguish sounds they need to hear to play well. Any band with drums in a small area is already making it tough for the vocalists to pitch even, let alone put in articulation and dynamics. Given that the dimensions of most of the places we play are around the wavelength of sub frequencies bass in enclosed spaces tends to be highly reverberant and therefore muddy. Making it harder for everyone to hear will produce the natural response to turn up and you have a volume war. Nobody wins a war.

Secondly the stage is full of mics. They' re going to pick up that bass and pass it on to the desk, even if you filter at the desk a little will get through and you aren't going to filter the kick mic most of the time. If the stage is wooden then the transmission will be through the floor and up the stands. Uuurghhh!

For me the best set up on stage is to gradually roll off the deep bass on your rig and to balance that up by rolling it back in at the PA. If you do it right you get all the upper bass/low mids delivered to your ears (the mids are more directional so you can have more me) the band get enough bass to get the changes right and can still hear what they need. The audience get a balanced sound and the singer gets a chance to deliver their best. Obviously in ears would deliver this differently but generally the lower the sound levels on stage the better and we ought to be thinking of what we don't need on stage, not adding to it.

 

 

[Al Krow]

14 hours ago, Chienmortbb said:

Mackie Tops are also far from ideal. To be fair I am talking about the Thump series and I have not come across a more overated (power wise) or poorly designed product,  but then I don't get out much.

 

Sounds like spending the extra on RCF quality for our sub and tops may have been no bad thing? Although the better value Alto, QSC, Headrush and Thomann gear all seem to be getting a good reception on here.

[Owen]

To be fair, I would be pushing QSC in the direction of RCF quality rather than Alto etc. 

[Al Krow]

10 minutes ago, owen said:

To be fair, I would be pushing QSC in the direction of RCF quality rather than Alto etc. 

 

Makes sense. I guess RCF are still setting the bar in terms of quality then?

[Phil Starr]

Hi Al, coincidentally last weekend we put the QSC 12's my band use to the test with some frequency response charts. They are sometimes criticised for their 'harsh' treble and we did measure some problems there. They are still fine speakers but if your RCF 310A's are loud enough for you then with subs they make an excellent system. I use a pair for our duo and as monitors for our band and for an open mic/jam session I used to run. They are really well behaved high quality speakers. There just aren't any sonic nasties there so they can be pushed to really high levels without causing feedback. I've just spent a long weekend this weekend using them for everything for the duo; bass, guitar and two vocals with no backline and they have sounded so good. I'm not a strong singer, plenty loud enough but my pitching isn't secure without decent monitors and these offer the best vocal sound I've ever got from the PA including top quality hired in systems with pro floor monitors. I've never had a better bass sound than I get from these up on poles and the acoustic guitar sounded, well like an acoustic guitar.

 

A pair of these with subs would be a great system but put them in front of the stage if you can and if you have two subs they are better acoustically together as Bill Fitz Maurice has said over and over again. Although I tend to let the practical consideration of stopping drunk punters knocking into stands sometimes override the sound considerations

 

As to crossover why not ask RCF? As a general principle I'd crossover higher rather than lower and as BFM has said a bit of experimentation should guide you. However as a general principle any frequency irregularities related to a compact cab are going to be centred around the 100-140Hz area and excursion limited power handling issues below 100Hz so a 120-150Hz handover of duties looks good to me. The higher the frequency the less power gong to the tops might also be a consideration. But these are general principles/rules of thumb I have no knowledge of the particular characteristics of the subs you are using.

[jazzyvee]

Duplicate post please delete

Edited December 8, 2021 by jazzyvee
Duplicate post

[jazzyvee]

On 06/12/2021 at 14:06, Al Krow said:

 

 

Useful suggestions gents. I'm sure the BF LF800 will deliver all the bottom end you need. @W1_Prowhich Thomann model did you go for? The CL 112 Sub is rated at 120W RMS going up to 1000W RMS for the Pyrit 212 SubA but looks great value at £525 including VAT. 41kg is going to much for my aging back, though!

 

I'm not sure what folk would reckon is a decent min with a full rock band? My RCF 702 AS ii delivers 700W RMS and is a more manageable 17.5kg / 39lbs which seems to be a decent power / weight compromise for our needs.

 

Here is a clip of the first time i took the LF800 out with the Schertler Unico. The DB,  keyboards and bass drum went into the schertler and LF800  fed by it's sub output. It was also my second full gig on DB. Sounded great in the outdoor undercover venue and the groove seemed to satisfy.

https://youtu.be/8to9vW16jB8

 

Edited January 3, 2023 by jazzyvee

[Al Krow]

@Silvia Bluejay another one to move to the PA sub-forum please. 

[Al Krow]

alto tx212s subwoofer  On sale at PMT for < £350.  20kg weight is very appealing, but is a single sub delivering 450W RMS going to cut the mustard?

 

Maybe worth paying the extra and getting something like this (1,200W RMS): Alto Trusonic TS12S Active Powered Subwoofer and figuring out how best to manage handle the additional weight?

[Bill Fitzmaurice]

Subs don't deliver watts, they deliver decibels. There's no direct correlation between the two. There is a direct correlation between cabinet size and driver displacement and how low and loud a sub will go. The larger size of the TS indicates it would probably go lower, the larger voice coil indicates it might go louder, but since there is no measured SPL chart or driver displacement shown there's no way to make an accurate objective comparison. As to one 12" sub being adequate it probably would be if the mains are 8", but that's about it. The mains are the tip of the iceberg you can see above the water. The subs are that part that's underwater. They need to be at least twice the size and cone displacement as the mains.