If you think you don’t need EQ, you haven’t tried it

[ellisdj]

I'm doing the calcs first to see what headroom I have. I just spoke to Ben Lilly at ATC about it, clearly it won't "fix" a room node (only moving position or treating the room or adding a sub could do that), but the parametric EQ could extend the bass reponse a bit further, bearing in mind it's natural roll off is -6dB at 48Hz. Of course, any hotspots will get hotter, and a node will stay as a node.

he also told me that the DSP adjustments can cause pahse shifts, so Steve is correct! The idea is to keep the Q factor low, so avoid sharp peaks, keep them smooth and gradual to minimise any phase problems. Ultimately, it's a more scientific solution than simply lifting up the sliders on the EQ studio to guesstimated levels.

Why I agree to the text book giving the speakers a little boost on the low end to try and improve the extension seems a good idea on paper

In reality the bass response you will be getting will be far from text book - so you could be wasting your time. If you are putting effort into something then learning how to measure is much better use of that time.

Otherwise its also psychoacoustic's as you will never be able to properly tell what its done if anything

 

[SteveR750]

I'm not trying to EQ the room! I'm trying to offset the natural roll off of the SCM40s by lifting the bass. Like I said, i could simply add EQ (or just turn up the bass control if the amp had it) to a subjectively better level, or i could analyse the natural roll off of the drive unit, and specify the new roll off point and apply EQ to hit that target. In natural form, the F0 of the speaker is around 60hz, with EQ, I can artifically change this to a lower frequency, ideally this would be to extend the flat response to 40Hz. By my current calcs, that requires a 6dB lift at 40Hz, so I'll need 4 times the power at a given SPL. A gentler boost would be to set a F0 target of 50Hz, which is only a 3dB lift, which is well within the SPL requirements and power from the Hegel.

Ultimately, all I am doing is using a quantitiative approach to flatten the response of the bass driver, and provide a boost to the LF. The room interaction will of course remain unchanged.

 

[SteveR750]

I'm doing the calcs first to see what headroom I have. I just spoke to Ben Lilly at ATC about it, clearly it won't "fix" a room node (only moving position or treating the room or adding a sub could do that), but the parametric EQ could extend the bass reponse a bit further, bearing in mind it's natural roll off is -6dB at 48Hz. Of course, any hotspots will get hotter, and a node will stay as a node.

he also told me that the DSP adjustments can cause pahse shifts, so Steve is correct! The idea is to keep the Q factor low, so avoid sharp peaks, keep them smooth and gradual to minimise any phase problems. Ultimately, it's a more scientific solution than simply lifting up the sliders on the EQ studio to guesstimated levels.

Why I agree to the text book giving the speakers a little boost on the low end to try and improve the extension seems a good idea on paper

In reality the bass response you will be getting will be far from text book - so you could be wasting your time. If you are putting effort into something then learning how to measure is much better use of that time.

Otherwise its also psychoacoustic's as you will never be able to properly tell what its done if anything

Well, it's no more a waste of time than randomly turning up a bass control until it sounds "OK", so in that respect there is indeed a large element of psychoacoustics, but at least the lift I'd be applying has some logic to it, if only that the output of the driver is going to be closer to that of a larger box with a more extended bass response. There is a difference between applying EQ to correct room deficiencies in an attempt to obtain the speakers specified bass response, and adding EQ because of the limit of the loudspeaker design.

The room measurement and correction is another step in the process, one which requires ££s as well as time, and even if it's measured, and let's assume that I can make the room response as flat as is economically possible, why would, or even should I prefer that balance?

 

[hoopsontoast]

If you want to extend the bass, rather than EQ out peaks then a seperate Sub would be a better option.

I would leave the speakers alone, the sealed enclosure on the SCM40s is an advantage as sealed speakers are generally easier to integrate with subs. You could also use DSP to integrate the SCM40 and Sub as well, to get the best integration.

 

[ellisdj]

It wont be flat - it will be far from flat - more like a mountain range of sorts unless your bloody lucky

Its not about it being flat anyway its about there being any point in trying to extend a range you have no idea whats there already.

I appreciate you are trying to achieve a deeper extension from the speaker, which is different to the effects room intercation. My point is you dont know the effect of the room interaction and that could easily negate the hard work done elsewhere. Although learning new skills is fun

REW costs very little to use if your pc has a soundcard - a radioshack spl metre is good enough, I have bought 2 over the years for £20 used and £30ish new - plus cost of a 9V battery. You might need a few cables but these are only pennies really off ebay.

Example removed as its not relevant -- sorry

 

[hoopsontoast]

Yep, my measurement 'system' is:

MiniDSP UMIK-1 Microphone ~£50

Behringer UCA-222 (USB Soundcard Input/Output DAC) ~£25

Any 3m+ Interconnect for UCA into Amp, the UMIK-1 comes with a 3-4m USB cable.

REW is free as well, just need to register on the Forum Website.

Its all pretty cheap stuff, and works really well, the Behringer is also handy for a cheap USB DAC too.

 

[SteveR750]

Thanks chaps for your input / advice, very welcome. I've had a play around with various settings, and my conclusion pretty much concurs with your comments - it certainly doesn't improve the sound quality, in fact, I've turned all EQ off as it sounds more natural. I don't have all of the parameters need to be sure of thee system Q and F3, but Ben told me the Q target is between 0.5 and 0.65, and I'm guessing the -3dB at 55Hz. Using a q of 0.6 and F(0) of 40Hz, the bass output was definitley increased, you could see that from the driver excursion (I had a 12dB/Oct high pass filter set at 15Hz), but when switched in, the system volume is reduced dramatically, so I've goen from an arbitrary "55" volume setting to around 75. AFAIK the volume setting is not references off 0dB, so the numbers are pretty meaningless, but it was a big drop in overall track volume.

So, it was an interesting subjective experiment, and really needs to have some in room measurement. Agreed that the most effective method for bass extension is a sub, but that is another thread...If nothing else, I now know how to set up and use the PEQ function within J River, which is something new, and potentially much more useful if I eventually install a sub.

 

[matt49]

I'd have been surprised if you'd have got much of an improvement, Steve. As I understand it, you were trying to improve speaker performance, not address room issues. There are ways of doing the former (e.g. Devialet's SAM), but they require sophisticated modelling of the speaker's performance.

On the other hand, if your speakers went lower by themselves, I'm pretty sure some EQ would be helpful to remove bass peaks.

 

[SteveR750]

Absolutely Matt, but it was fun experimenting. Some songs just require a brutal chest crushing bass thump, to be honest I don't think my bouncy floored wooden construction lounge / house is ever going to deliver that!

 

[matt49]

Absolutely Matt, but it was fun experimenting. Some songs just require a brutal chest crushing bass thump, to be honest I don't think my bouncy floored wooden construction lounge / house is ever going to deliver that!

Hmm ... methinks you need a pair of Phantoms: the only speakers I've heard that can generate the sound of a kick drum in a domestic space.

As far as the bouncy floor's concerned, Townshend isolation bars are excellent, if pricey. Auralex Grammas are much cheaper, though I;ve not tested them.

 

[steve_1979]

I've only made adjustments by ear and haven't had the chance to take any measurements yet as I dont have the equipment but hopefully at some point in the future I'll get some proper DSP for the sub and possiblily even for the stereo speakers too. It'll be interesting to give it a try to see what effect it has.

At the church of AVI Ash says that DSP is generally bad (unless you have a major bass issue) because using DSP effects the phase and it doesn't usually matter much if the frequency response in room isn't perfect because your ears hear the speakers first and your brain uses as a reference and it will automatically filter out the sound of the room subconsciously. I'm open minded and am willing to give it a try anyway.

With Ash it's marketing, marketing, marketing. Some of which is based in reality, most of which is just marketing nonsense.

AVI don't use DSP. Therefore Mr James says it's generally bad.

AVI don't use passive crossovers, Therefore Mr James says they're 10's / 100's / 1000's times worse than active.

AVI use 2 way speakers with an optional sub. Therefore 3 / 4 / 5 ways are worse according to Mr James.

AVI make small speakers with a small optional sub. Therefore large speakers are worse according to Mr James.

AVI use current in-production drivers. Therefore old speakers are just there to be ridiculed by Mr James.

AVI don't use valves. Therefore valve amps are lacking in fidelity according to Mr James.

Yada, yada, yada. And so on.

What's more likely? That most of what Mr James says is true and the AVI way of doing things is the best way? Or that he's using reverse engineering marketing, where he makes up nonsense where he talks about the AVI way of doing things as the best way and any other way as inferior?

Get an anti-AVI system (analogue, vintage, passive, with valves, 3 / 4 / 5 way, large speakers, etc etc etc) in the same room as an AVI system and listen to them. If Mr James marketing had any merit at all, the AVI system would sound significantly superior.

His pronouncement on DSP is just another one of his marketing fantasies. The reality of DSP is that it's all "Ifs and buts" and "it depends".

Believe it or not I do take what Ash says with a pinch of salt but at the same time his comments still have more credibility than most for me because Martin Grinrod builds the best speakers that I've heard* so they must be doing something right. Martin designs his speakers to be as close to phase perfect as possible over the crossover region as a high priority.

As I say I'm open minded so I'm willing to give DSP a try on the sub at some point then if I don't like the change than I can sent it back. I've heard DSP used to good effect on some Genelec monitors before now.

* I appriciate that different people have different tastes but to my ears at least they are the best.

 

[SteveR750]

Absolutely Matt, but it was fun experimenting. Some songs just require a brutal chest crushing bass thump, to be honest I don't think my bouncy floored wooden construction lounge / house is ever going to deliver that!

Hmm ... methinks you need a pair of Phantoms: the only speakers I've heard that can generate the sound of a kick drum in a domestic space.

As far as the bouncy floor's concerned, Townshend isolation bars are excellent, if pricey. Auralex Grammas are much cheaper, though I;ve not tested them.

Bring them to Colin's!

 

[matt49]

Absolutely Matt, but it was fun experimenting. Some songs just require a brutal chest crushing bass thump, to be honest I don't think my bouncy floored wooden construction lounge / house is ever going to deliver that!

Hmm ... methinks you need a pair of Phantoms: the only speakers I've heard that can generate the sound of a kick drum in a domestic space.

As far as the bouncy floor's concerned, Townshend isolation bars are excellent, if pricey. Auralex Grammas are much cheaper, though I;ve not tested them.

Bring them to Colin's!

Yes, will do. He will need a structural survey of his house first though. *angel*

 

[Gazzip]

Right, this sounds excitingly dangerous. I was reading through the J River wiki to check on phasing in DSP settings, and investigated the parametric equaliser that's included in the DSP settings, and stumbled across something called the Linkwitz Transform. Clearly if not handled with care, it's either going to fry the amp, and or fire the bass mid drivers across the room and possibly kill the cat...

I'm going to try to see if there is enough power and excursion to be able to offset the -6dB at 48Hz spec so that they are flat to 40Hz (bass guitar bottom E) and then introduce a steep high pass to preserve any remaining headroom. Let's see how the calculations go first...

Steve, please, please, please do not upset the space time continuum again with another crazy science experiment. The Linkwitz Transform is clearly another name for the Flux Capacitor and I have only just got my system right at last. Try not to send us all back to 1991 as I don't think I can stomach going through my Audiolab years again!

 

[SteveR750]

Absolutely Matt, but it was fun experimenting. Some songs just require a brutal chest crushing bass thump, to be honest I don't think my bouncy floored wooden construction lounge / house is ever going to deliver that!

Hmm ... methinks you need a pair of Phantoms: the only speakers I've heard that can generate the sound of a kick drum in a domestic space.

As far as the bouncy floor's concerned, Townshend isolation bars are excellent, if pricey. Auralex Grammas are much cheaper, though I;ve not tested them.

Bring them to Colin's!

Yes, will do. He will need a structural survey of his house first though. *angel*

*bomb* Sounds like a challenge

Steve, please, please, please do not upset the space time continuum again with another crazy science experiment. The Linkwitz Transform is clearly another name for the Flux Capacitor and I have only just got my system right at last. Try not to send us all back to 1991 as I don't think I can stomach going through my Audiolab years again!

Too late, I'm halfway though rebuilding Trevor

 

[drummerman]

Had I got an EQ, I'd probably be constantly fiddling with it, depending on source and music!

I remember it was bad enough with a DAC I had and switchable digital filters.

As is, I take care how I set the system/s up and just enjoy but I can certainly see why having one could be handy on occasions.

 

[SteveR750]

I was listening to Breathe off Dark Side this morning, and the heartbeats are extremely deep bass. I tried tweaking the standard EQ boost at 60Hz, and it got out of control at moderate listeing levels. I've got a unit in the lounge which has a glass display cabinet full of my "special" stemware, and they were rattling along. It's clear that the lowest frequencies are attenuated, but the ear is pretty good at allowing for natural order roll off, so whilst technically it's missing, subjectively there's enough information present. I suspect the room is quite excitable, and I really wouldn't be surprised if a proper measurement showed there to be some significant humps below 100Hz.

There's another thing I've learnt, and that is I have not lost that childlike fascination with watching speaker cones vibrate massively. It's like making / watching a fire, almost hallucinatory!

 

[LDTM]

There's another thing I've learnt, and that is I have not lost that childlike fascination with watching speaker cones vibrate massively. It's like making / watching a fire, almost hallucinatory!

Pair that with a whacking great pair of VU meters and there is enough distraction for even the most attention span challenged. *biggrin*

 

[SteveR750]

There's another thing I've learnt, and that is I have not lost that childlike fascination with watching speaker cones vibrate massively. It's like making / watching a fire, almost hallucinatory!

Pair that with a whacking great pair of VU meters and there is enough distraction for even the most attention span challenged. *biggrin*

I've never owned an amp that had them, I have missed out. I miss cassette decks for that reason too, there was an art in trying to record with the optimum S/N ratio. It all started to go wrong when LEDs took over...

 

[Infiniteloop]

Songs are mixed in a very different manner and its far from beeing that absolute science puriste refer to. Its very random how bass levels are adjusted and will depend on so many uncontrolled factors. The absolute proof is when we listen at the same level on our system there are huge bass level difference from a song to another. There is also the differences from day to day because hearing varys too. I experienced how a flu, tiredness, coming out of a noisy place, alcool, ... will all change how much bass we hear. For me when bass lacks its the soul of the song thats missing and I use equalizers a lot. When I listen to london grammar, Hey Now its one of those rare songs I get enought bass at flat otherwise I crank it up.

+1. London Grammar's 'If You Wait' was one of my fave albums of last year for both artisic merit, content and SQ.

 

[Gazzip]

Too late, I'm halfway though rebuilding Trevor

He's alive! ALIVE!

 

[iQ Speakers]

Absolutely Matt, but it was fun experimenting. Some songs just require a brutal chest crushing bass thump, to be honest I don't think my bouncy floored wooden construction lounge / house is ever going to deliver that!

Hmm ... methinks you need a pair of Phantoms: the only speakers I've heard that can generate the sound of a kick drum in a domestic space.

As far as the bouncy floor's concerned, Townshend isolation bars are excellent, if pricey. Auralex Grammas are much cheaper, though I;ve not tested them.

Bring them to Colin's!

Yes, will do. He will need a structural survey of his house first though. *angel*

Well if I can arrange it shortly the scaffolding should still be up! Can wait to hear those Dev's and the Hegel!

 

[SteveR750]

Absolutely Matt, but it was fun experimenting. Some songs just require a brutal chest crushing bass thump, to be honest I don't think my bouncy floored wooden construction lounge / house is ever going to deliver that!

Hmm ... methinks you need a pair of Phantoms: the only speakers I've heard that can generate the sound of a kick drum in a domestic space.

As far as the bouncy floor's concerned, Townshend isolation bars are excellent, if pricey. Auralex Grammas are much cheaper, though I;ve not tested them.

Bring them to Colin's!

Yes, will do. He will need a structural survey of his house first though. *angel*

Well if I can arrange it shortly the scaffolding should still be up! Can wait to hear those Dev's and the Hegel!

It had a bit of a workout the other day playing around with those Lipwitz transforms, especially when I cranked it up a bit.

 

[gasolin]

If you want to test your speakers/subwoofer try playing the cranberries song no need to argue

 

[matt49]

Here are more graphs. These were done with a UMIK-1 microphone feeding REW on my laptop.

Before EQ:

After EQ with DSPeaker Anti-mode 2.0: