Integrating Subwoofers to Main Rig Speakers

[XTRProf]

By measurement, shouldn't have much of a problem. Yeah, the twist is by ear as I don't have equipment. Later on, fine adjust by measurement after acquiring them. Btw, what measurement software you guys recommend? Free, is best obviously. My case is a stereo system and not a HT setup.

Parameters are the usual gain, digital parametric equaliser (2 points), crossover and phase. What should we look out for by ears? I have 2 12" active subs of 600 W rms and 1000 W peak.

Also, as the subs are producing so much power on bass, they do start to rattle themselves when on spikes on ceramic tiled floor. How to eliminate those rattles. Yeah, I know, my bloody doors, window panes and cabinets also need to be looked into. But I do enjoy the little brother below me shaking on the occassional deep bass slam. But not for too long though.

[Deleted]

Sub-woofers can introduce more problems that they're worth, you know.

The most common thing that many do, is to have them set far too loud and you get this unpleasant 'boom' in the sound that everyone seems to think is hi fi!!

It's also quite critical which frequency it's working at since some may overlap too much with the speakers themselves, so you introduce a nice fat hump in the sound.

Not to mention room resonances which you can really enhance with a sub-woofer!!

When I used them, I turned them off and gradually crept them up when I had some rock/pop bassy stuff on until I could just detect that they were contributing ...... and then I slightly backed them down again so that they only really appeared on fat bassy sounds.

Nothing becomes more annoying to me than that boom, boom, boom sound you can get from them.

BTW, cheapy sub-woofers are truly nasty. The bass has no pitch to it and it just rumbles. I'd rather have no bass.

There are some good ones, but they can be quite expensive. I think the one I had was a REL.

I even crept around the room with a sound meter to look for hotspots and standing waves!! It's quite amazinf what the subwoofer was introducing into the mix and I ended up leaving it off.

[Deleted]

When I used them, I turned them off and gradually crept them up when I had some rock/pop bassy stuff on until I could just detect that they were contributing ...... and then I slightly backed them down again so that they only really appeared on fat bassy sounds.

Exactly my experience with subs as well.

I must admit I have never seriously tried to integrate one into a normal stereo set up. I have successfully done so for many surround sound systems of varying standards. I've only had hands-on experience with the RELs and ATC, oh, Tannoy as well but they were cheap and nasty.

I like bass but not constant thumping or droning. As Ian said, they should only make themselves noticable when truly deep bass material is present, like the scene at the beginning of Terminator 2 when the robot crushes a skull underfoot. On a decent system you can feel that one in your bowels!

I know they are popularly used to augment "bass shy" 'speakers like Quad ESLs (not my claim) but I have no lasting positive experience of this.

[XTRProf]

Mar 6, 2012 8:40:07 GMT @iancraig10 said:

Sub-woofers can introduce more problems that they're worth, you know.

The most common thing that many do, is to have them set far too loud and you get this unpleasant 'boom' in the sound that everyone seems to think is hi fi!!

It's also quite critical which frequency it's working at since some may overlap too much with the speakers themselves, so you introduce a nice fat hump in the sound.

Not to mention room resonances which you can really enhance with a sub-woofer!!

When I used them, I turned them off and gradually crept them up when I had some rock/pop bassy stuff on until I could just detect that they were contributing ...... and then I slightly backed them down again so that they only really appeared on fat bassy sounds.

Nothing becomes more annoying to me than that boom, boom, boom sound you can get from them.

BTW, cheapy sub-woofers are truly nasty. The bass has no pitch to it and it just rumbles. I'd rather have no bass.

There are some good ones, but they can be quite expensive. I think the one I had was a REL.

I even crept around the room with a sound meter to look for hotspots and standing waves!! It's quite amazinf what the subwoofer was introducing into the mix and I ended up leaving it off.

No worry, these are the latest high quality type for music and HT and not the old boom, boom, boom type. I see your point of making the sub just be heard and then backing off. Noted. I also have the same thinking and so at present the bass from the sub can just be heard to give the whole soundstage picture a volume of it's own. Really I can hear a much better recording space with the different images of singer and musical instruments within that, I would say, black hole or window or portal. So that's confirmed here with you guys.

The X-Over fat hump in the sound can only be reduced further when there is objective measurement and passive or active crossover introduced between the pre and power amps. But as for now, can we reasonably assume that a normal size floorstander of the usual suspect size will start rolling off at around 70 or 60 Hz? Prof Frans, what say you? So 75% of 65 Hz = 50 Hz set for the low pass filter in the sub? Reasonable. What say all for this temporary measure? Btw, my floorstander is ported so should have a lower limit before roll off.

Ah, I see that you did the bass crawl. Is that what your studio guys told you to do or your hifi dealer?

[XTRProf]

Mar 6, 2012 9:15:38 GMT @cjarchez said:

When I used them, I turned them off and gradually crept them up when I had some rock/pop bassy stuff on until I could just detect that they were contributing ...... and then I slightly backed them down again so that they only really appeared on fat bassy sounds.

Exactly my experience with subs as well.

I must admit I have never seriously tried to integrate one into a normal stereo set up. I have successfully done so for many surround sound systems of varying standards. I've only had hands-on experience with the RELs and ATC, oh, Tannoy as well but they were cheap and nasty.

I like bass but not constant thumping or droning. As Ian said, they should only make themselves noticable when truly deep bass material is present, like the scene at the beginning of Terminator 2 when the robot crushes a skull underfoot. On a decent system you can feel that one in your bowels!

I know they are popularly used to augment "bass shy" 'speakers like Quad ESLs (not my claim) but I have no lasting positive experience of this.

Great, this further confirmed what is written above. Yup, I have that same feeling a well.

Btw, cone subs usually don't match well with planar or ESL type of speakers due to the much discrepancy in mass of the drivers. Maybe they were the older boom, boom, boom type. I'm not sure about the present "hifi" and HT ones though. Prof Frans, what say you?

I'm still not very sure how to adjust phase by ear. What should we be looking out for by ear? Have not done that yet and had left it at 0 degree.

[Deleted]

Google for SynRTA - a free (windows) program. I have used this to 'see' what's happening in real time when the sub is active. For relative, rather than absolute, measurements any old microphone will do the job and I use my Shure SM58 for example. I used it to tune the sub to give me as much reinforcement low down as it could without adding to anything in the 100Hz region.

I was encouraged to find that SynRTA just gave me support for the settings I had arrived at 'by ear'.

Free and fun.

Derek

[Deleted]

Ah, I see that you did the bass crawl. Is that what your studio guys told you to do or your hifi dealer?

Studio guys. The also started me with mirrors to work out where reflections come from. If you place an upright mirror on the left and then the right wall - move it along the wall until you can see a reflection of the speaker in the mirror from the sitting postion. That's where you can place sound dampers to stop unwanted reflections. (and the ceiling!!)

Then if you move around the room, you may notice the bass coming and going. Standing waves and all kinds of things going on.

For some reason, a sub-woofer pointed out many reflections in my place.

I turned it down to a point where you would think it was off. Then when you got a big bang, you really did get a big bang!!!! As Chris said - like in Terminator - it's gut wrenching. If you have the sub too loud - it's gut moving for sure and makes me feel a bit sick. Bit like when you go to a poorly eq'd pop concert.

BTW, don't put the sub in a corner!!! It almost doubles its power of destruction!!!!

[rowuk]

I have had the best luck with 3 subwoofers placed in 3 completely unsymmetrical places in the room and crossed over no higher than 70-80 Hz. You excite basically all of the resonant modes that way and can turn the subs WAY down with little to no boom and an excellent sense of pitch. Single subs are a desaster as are subs under each speaker. Start at low volume and turn them up slowly.

As far as spikes on ceramic, it really does not help tighten the bass up. I would use hard rubber feet on ceramic and wood, spikes on concrete.

True bass is moving air (unless you are in a small, closed room (like a car) where the air pressure determines what you feel. That means a high quality 12 or 15" woofer is going to do a better job than a small 10" or less.

Integrating the subs cannot be done with a meter, you HAVE to use your ears. The reason is the pressurized chamber effect that I mention above. It is really hard to measure as it applies to your hearing.

[XTRProf]

Mar 6, 2012 10:10:45 GMT hifidez said:

Google for SynRTA - a free (windows) program. I have used this to 'see' what's happening in real time when the sub is active. For relative, rather than absolute, measurements any old microphone will do the job and I use my Shure SM58 for example. I used it to tune the sub to give me as much reinforcement low down as it could without adding to anything in the 100Hz region.

I was encouraged to find that SynRTA just gave me support for the settings I had arrived at 'by ear'.

Free and fun.

Derek

Excellent, Derek! For those interested in the freeware, here is it:


www.libinst.com/SynRTA.htm


I've downloaded it but now what full frequency (10hz to 30khz)microphone to buy since I don't have any mic around? Anybody? maybe my inbuilt laptop mic is not good enough and I will use the laptop to measure obviously for convenient.

[XTRProf]

Mar 6, 2012 14:03:29 GMT @iancraig10 said:

Studio guys. The also started me with mirrors to work out where reflections come from. If you place an upright mirror on the left and then the right wall - move it along the wall until you can see a reflection of the speaker in the mirror from the sitting postion. That's where you can place sound dampers to stop unwanted reflections. (and the ceiling!!)

Yup, from the look of things those guys you spoke to are certainly highly qualified as they obviously did the full Audio Engineering course to be able to tell you that.

Mar 6, 2012 14:03:29 GMT @iancraig10 said:

For some reason, a sub-woofer pointed out many reflections in my place.

Er, your "hifi" room is with wall paper, curtains, sofas or even maybe a bookshelf?

Mar 6, 2012 14:03:29 GMT @iancraig10 said:

I turned it down to a point where you would think it was off. Then when you got a big bang, you really did get a big bang!!!! As Chris said - like in Terminator - it's gut wrenching. If you have the sub too loud - it's gut moving for sure and makes me feel a bit sick. Bit like when you go to a poorly eq'd pop concert.

Yup, that's where I'm presently at. It's not the boom, boom, boom type but bass with, like what you had said, pitch and you can hear there is a rythm and tune in the bass. Is the bass that in Live music? Heavenly literally with a scary window looking into an imaginary recording venue with all the members of the mix, the singers and musicians, occupying and layered in a specific place in that window in an even more 3D way. Now the depth has increased too. I could never attain that without the sub no matter how high end I wanted to go. Too much bass really make me sick too. It's like I'm down in hell.

Mar 6, 2012 14:03:29 GMT @iancraig10 said:

BTW, don't put the sub in a corner!!! It almost doubles its power of destruction!!!!

Even for speakers in general too unless they are designed for against the wall placement.

So overall, the subs when tuned and placed properly do enhance overall feel of the music in a very enjoyable way. Yeah, forget all the boutique caps, cables, etc. Pound for pound, the sub WILL ENHANCE the music enjoyment more than those. So if you have say 300 pounds to spend, spend it on a sub and properly tune it up will be more worthwhile than spending on boutique caps, cables, etc when your system is already good sounding. Forget about the miracle wraps at this point.

[XTRProf]

Mar 6, 2012 22:33:14 GMT rowuk said:

I have had the best luck with 3 subwoofers placed in 3 completely unsymmetrical places in the room and crossed over no higher than 70-80 Hz. You excite basically all of the resonant modes that way and can turn the subs WAY down with little to no boom and an excellent sense of pitch. Single subs are a desaster as are subs under each speaker. Start at low volume and turn them up slowly.

Thanks. For the third time, you have confirmed basically what the rest concured thru ears and that is the sound with sub should not be boomy and overwhelming the music. Turn it up to a point where, like Ian had said, that we think the sub is off but will crack with a boom when there is real deep bass offered.

By having multiple subs, you have brought to the table the truth of a more homogenous and uniform bass thru out the room. For that reason alone, I do have 2 12" subs as mine is stereo, one for each channel. Btw, you using the LFE signal or stereo or multichannel signal for each sub?

I would also like 15" subs but the listening place I'm in is not kind for that size. Most 15" subs are pretty big in form factor to be practical unless we have a very big listening place for our listening. Also, the WAF is low for sure.

Mar 6, 2012 14:03:29 GMT @iancraig10 said:

As far as spikes on ceramic, it really does not help tighten the bass up. I would use hard rubber feet on ceramic and wood, spikes on concrete.

Yeah, I'm having problem with that currently as the subs rattle on their own about the ceramic floor when deep bass comes in. I'll changed to the rubber "spikes" supplied as well to see how things go.

Btw, have you place the subs on any isolation platform to further improve the sub sound quality? Something like Subdude. With that, I think will use the metal spikes again as that will already anchor the subs well to prevent it from rattling. That's the problem with current subs. They produce so much power (600 Wrms, btw) to rattle about on their own when thye are not heavy enough.

[XTRProf]

Yeah, so far anybody know how to tune sub phase by ear?

[xerxes]

Yeah, so far anybody know how to tune sub phase by ear?

My sub has a remote, so I mess about with it until it sounds right. I put the frequency and volume quite high to start with, then back them off until the sub is not longer overtly apparent. When it's about right, it's not obvious that it's there until you turn it off. When it's on it makes the sound bigger and fuller without messing up the imaging or sound stage.

[XTRProf]

Mar 7, 2012 16:28:33 GMT xerxes said:

My sub has a remote, so I mess about with it until it sounds right. I put the frequency and volume quite high to start with, then back them off until the sub is not longer overtly apparent. When it's about right, it's not obvious that it's there until you turn it off. When it's on it makes the sound bigger and fuller without messing up the imaging or sound stage.

Yup, that's what I did as well. Same as you, there is a point where everything snaps togather in a very nice and pleasant way and straight away transport us into an imaginary space of a lounge or club environment with live band.

For sub volume, my setting is at +4db. This is the ideal vol setting where there is no noticeable bass, as if the sub is off, when there is no deep bass. For frequency, the final is at 70hz. I had started off the frequency at 90 hz, as the roll off frequency for floorstanders of the size I'm having is around 80hz. At that, it was just too boomy so I lowered and lowered it until 70 hz and there was a very good sense of an imaginary recording venue where all the singer and accompanying musicians were layered properly in a more 3D space. As I lowered further from 70hz, there seems to be opening more and more of a hole in the frequency spectrum and everything seesm very disjointed and there is just not continuity. Also, the nice imaginary recording space with all the nice 3D layered members of the music group was going and going and was finally gone, more 2D now, at the hammer at 50 hz, my first calculated guess. So my earlier assumption of the floorstander roll off at 65 hz was wrong and the THX recommendation of around 80 hz is correct. As my floorstanders was ported, it does have a lower roll off frequency and so 70 hz is a reasonable bet. All the estimated technical and the subjective did jive togather and I'm now temporary in music heaven until I understand to tune the phase by ear.

[XTRProf]

Wow, I played this album again. I didn't know I was missing so much bass. Yeah, we can hear the bass is with pitch and there is a tune to it. So all the sibilance that I had complained about earlier is now all gone. I'm in music bliss, man! Try this CD on a HP and find what is missing from the HP (Yeah, any price and end) ...............

[xerxes]

70Hz is quite high, with my stand mount speakers, a pair of Dynaudio Audience 52SE, I found that a cut-off at around 40Hz was about right, so the sub is just filling in the bits where the speakers don't reach. Of course, room size, speaker placement and how "live" or "dead" the room is will make a difference.

[XTRProf]

Mar 8, 2012 6:17:01 GMT xerxes said:

70Hz is quite high, with my stand mount speakers, a pair of Dynaudio Audience 52SE, I found that a cut-off at around 40Hz was about right, so the sub is just filling in the bits where the speakers don't reach. Of course, room size, speaker placement and how "live" or "dead" the room is will make a difference.

Actually I wanted lower but at 60hz, the discontinuity is just too much already and I don't enjoy the sub anymore. Hope I can get a good mic to double check what was done is correct.

Btw, you having a single sub or double sub like me? Just curious.

[XTRProf]

Getting more and more in depth. Now I've bought the calibration CD and waiting for it to come.

Hmm, must source for a good mic. Before long I'll be going back to the army doing the leopard crawl. Oops, bass crawl like a baby around the floor. Arrrggh, we are having a second life again.

[Deleted]

To accurately measure woofers you will need to measure very near field in case of sinewave test-tones to get accurate readings.

Measuring at the listening spot is not recommended using sinewave test tones.

If your test CD has 'wobbled' tones or narrow noise bands you are likely to get better readings.

Make sure the used MIC AND preamp can handle subsonics and correction factors/freq plots are known.

Probably only using the ears will give best results.
Afterall it's all about how it sounds to you, not measurements.

a GOOD sub (well adjusted) one shouldn't notice at all, only that what was missing should suddenly be there.
Enhancing the experience.

HP's like DT1350, P5, LCD2-3 e.t.c. have similar 'extension'

[xerxes]

Btw, you having a single sub or double sub like me? Just curious.

I have a single sub, placed in the corner, as recommended by the manufacturer, to the right of the right speaker.

My speakers are rear ported with a frequency response, according to the specs: (+/- 3 dB): 45 Hz - 26 kHz. I imagine with a bit of room/rear wall reinforcement they could well get bass down to around 40Hz. One of the reasons I chose them was because they are quite punchy, certainly not bass shy, even without the sub.

I'd never really tried as sub so I bought one just to see if I liked it, and I did. I also picked one, a REL Stampede, that was said to work well for music, rather than one of the more home cinema oriented subs.

[Crispy]

BTW, don't put the sub in a corner!!! It almost doubles its power of destruction!!!!

Cheung,
I have two M J Acoustics Reference 100 active subs in my system.
The picture below is showing the right hand side, the left hand side is the same minus the CD, XCanV2 + psu. Note the sub is in the corner.


The freq response of my Acoustic Energy AE1's are 35Hz - 30Khz
and the freq response of the subs are 13hz to 120Hz.

They recommend that you should set the crossover to slightly above the lower freq response of your main speakers. EG: mine are set at 39Hz.

They say you should position your subs near to you main speakers, mine are near but in the corner of the rooms.

Then turn all controls to their lowest position.

Find a familiar piece of music with a good steady bass to listen to over and over while setting up the sub/s.

Increase the volume on the sub until the sub intrudes on the music then back it off.

The art is to mix in the sub so you can't tell where it's positioned - you just know it's there.

Initial set-ups may not be perfect at first, spend plenty of time auditioning and tweaking. The true art of blending in a sub is for it to go unnoticed.

REL recommend you place the sub as far into a corner as possible, then slowly pull it out from the corner diagonally inch by inch until it exhibits the lowest bass extension.

Check out the link below - it's a manual to set up a REL sub but you may get some useful tips.


www.sumikoaudio.net/rel/manuals/Q-Series-Manual.pdf

Have fun tweaking ;D

[XTRProf]

While searching for more bass tuning to feed the addiction, found this that could be better than the SynRTA. So here for your guys to try ..............



www.hometheatershack.com/roomeq/


No worries, Apple diehards, you are not forgotten too.

[Deleted]

EXCELLENT find !

great.... thanks

downloaded it !

[XTRProf]

Mar 8, 2012 11:43:10 GMT @solderdude said:

To accurately measure woofers you will need to measure very near field in case of sinewave test-tones to get accurate readings.

Measuring at the listening spot is not recommended using sinewave test tones.

If your test CD has 'wobbled' tones or narrow noise bands you are likely to get better readings.

Still trying to get my act togather. Same for the test tones. So far have these tones on order and perhaps on the way now ............ The test signals are:


1 Pink Noise LR -20dB 2 min
2 120 Hz LR -1dB 1 min.
3 110 Hz LR -1dB 1 min.
4 100 Hz LR -1dB 1 min.
5 95 Hz LR -1dB 1 min.
6 90 Hz LR -1dB 1 min.
7 85 Hz LR -1dB 1 min.
8 80 Hz LR -1dB 2 min.
9 75 Hz LR -1dB 1 min.
10 70 Hz LR -1dB 1 min.
11 65 Hz LR -1dB 1 min.
12 60 Hz LR -1dB 1 min.
13 55 Hz LR -1dB 1 min.
14 50 Hz LR -1dB 1 min.
15 40 Hz LR -1dB 1 min.
16 30 Hz LR -1dB 1 min.
17 20 Hz LR -1dB 1 min.
18 HF Contoured Noise -20dB 1 min.
19 LF Contoured Noise -20dB 1 min.
20 Holly Cole Jersey Girl
21 Holly Cole Don't Smoke In Bed
22 Techmaster PEB
23 Techmaster PEB
24 Techmaster PEB
25 White Noise LR -20dB 4 min.
26 White Noise LR 180 degrees out of phase -20dB 4 min.
27 80 Hz SINE WAVE BLIP test LR 60 sec
0dB FULL LEVEL ! One blip every 2 sec.
28 bonus track.


Also, have these as wav files:


1 Track 1: Monophonic Pseudo-noise sequence
2 Track 2: Monophonic Short Sine Sweep
3 Track 3: Monophonic Long Sine Sweep
4 Track 4: Monophonic Bass Sweep
5 Track 5: Left Channel, Pseudo-noise sequence
6 Track 6: Left Channel, Short Sine Sweep
7 Track 7: Left Channel, Short Sine Sweep, bass removed
8 Track 8: Left Channel, Short Sine Sweep, bass and midrange removed
9 Track 9: Left Channel, Long Sine Sweep
10 Track 10: Left Channel, Bass Sweep
11 Track 11: Right Channel, Pseudo-noise sequence
12 Track 12: Right Channel, Short Sine Sweep
13 Track 13: Right Channel, Short Sine Sweep, bass removed
14 Track 14: Right Channel, Short Sine Sweep, bass and midrange removed
15 Track 15: Right Channel, Long Sine Sweep
16 Track 16: Right Channel, Bass Sweep
17 Track 17: Warning
18 Track 18: Left Channel, 50 Hertz Tone for voltage measurement
19 Track 19: Right Channel, 50 Hertz Tone for voltage measurement


So far, have I missed out anything. The more comprehensive the merrier as I'm having a second life to build up a repository of test tones. I'm going objective for a change. So don't say I'm against objective anymore.

So Frans, which tracks you think will be the most appropriate to setup the subs? Yeah, much later on then talk about the environmental measurements and tuning (eq) to setup better the hifi in a home environment.

Mar 8, 2012 11:43:10 GMT @solderdude said:

Make sure the used MIC AND preamp can handle subsonics and correction factors/freq plots are known.

Oh, I'm thinking of a usb mic and quite a pro software that comes togather with the mic now. Let me get the act togather before I can tell you more. Too bad, I'm going broke for that as it's just too impressive. Yeah, I'm full steam technical now, baby.

Mar 8, 2012 11:43:10 GMT @solderdude said:

Probably only using the ears will give best results.
Afterall it's all about how it sounds to you, not measurements.

Hmm, quite uncharacteristics of you there.

Mar 8, 2012 11:43:10 GMT @solderdude said:

a GOOD sub (well adjusted) one shouldn't notice at all, only that what was missing should suddenly be there.
Enhancing the experience.

Thanks for the fourth confirmation. Yup, I have that now. Only haven't adjust the phase yet. Hmm, phase is about in phase and out of phase, right? So an "insane US style" guess, the subs must sound the loudest when the phase control is adjusted correctly?

Mar 8, 2012 11:43:10 GMT @solderdude said:

HP's like DT1350, P5, LCD2-3 e.t.c. have similar 'extension'

Oh, it's still so much different from the HP experience. Now we can listen and feel the music closer to Live. HP just give a whimp and the speakers with subs give a roar and shake the foundation like in Live. Technically obvious, right? Left Right amps a total of 700Wrms at 6 ohms and 2 subs a total of 1.2KWrms standby power giving a total of close to 2kWrms standby power. HP, let's take the most powerful that I know. 12Wrms total at the lower ohms. Hmm ........

Also, in speakers, we are totally immersed in the sound when loud enough as our body are covered by sound just like in a Live event. HP only our ears are covered. Yeah, technically it should not be any difference as our body don't "listen and hear". But I can tell you the experience is just that more "shiok" with the speaker system any time. If HP can replicate the Live event better, might as well attend a concert with the organisers giving out HPs to hear. Much lesser noise pollution if held in an open space. Yeah, so much cheaper and easier to organise with much lesser sound and light engineers and ground crew too. More green too as much lesser power is consumed. Oh, the logistics too for world tour.

[XTRProf]

Mar 8, 2012 13:12:47 GMT xerxes said:

I have a single sub, placed in the corner, as recommended by the manufacturer, to the right of the right speaker.

Actually 2 subs for a stereo system will be better if we read the forums on bass. This is because of the more uniformity of SPL across the room to give a more immersive experience. I tend to agrre with that. Rowuk have 3, btw, and I can imagine what he's having now. Of course, if only you can go for a second sub without breaking the bank and the wife throwing you out.

Rel really have a strange way to recommend the placement of the sub. Only the corner and the right speaker. If it was designed for corner placement, by all means. However, usually we have the nodes and antinodes to consider as well so placing a sub in the corner and right of the speaker might not give the best sound. That's a fact if we go just by technical.