The explanation is always helpful. Plus, and I hear dozens of teachers and administrators a year speak to groups, Paul is the model of HOW to speak to be understood with tone modulation, pitch, diction, and especially, near-zero filler sounds such as uh, um, ah, so, and an'. You're always a pleasure to listen to on a subject you are passionate about.
To get rid of dips, first get rid of peaks. In other words, don't raise the farm field to the height of the nearby mountains; instead, flatten the mountains to the level of the farm field.
Yes, unfortunately the peaks are caused by room modes and this requires room treatment not dsp. Lowing the level will never deal with the reverb, only the volume. Other than that, Paul is right, no matter how much energy you pump into a dip, it *will* still cancel.
i never had much issues with dips, but then i have a small room with a lot of absorption. having subwoofer like Paul said give you more options to fix the issue. i run dual subwoofers and full dsp on them, i can time delay them individually or with the main speakers, then i don't have to move them around. maybe a high pass on the main speakers also help in some cases.
DSP correction of higher frequencies can work really well for digital music when not adding sample rate conversion and when done in high resolution math. Unfortunately, DSP correction products usually end up messing with sample rate conversion e.g. translating a 44.1kHz PCM track to 48kHz or 96kHz before DSP compensating it. Someone needs to make a DSP correction product that can maintain end-to-end sample rate from source to DAC and do the processing in 32 or 64 bits math. Until then, Paul has a valid point about DSP compensation and higher frequencies.
I go to lot of jazz concerts, even at live events I can hear peaks and dips on the acoustic bass, so it really doesn't bother me when it happens in my listening room.
Resonating bass frequencies are all part of the natural way music sounds in certain venues,,, you make your point very well indeed. We sometimes forget how music sounds out there in the real world and want to tame it for home use!
I've not tried it, but what about having two subs with one phase adjustable (0 to 360 degrees) - would it help or create more chaos? :) Great video Paul - it's remarkable how you keep the curiosity flowing after so many videos, well done.
I think you would be playing "wack a mole" at that point, giving up one dip for two smaller dips. Outside of the sweet spot it might get really wild, and you would loose bass definition in the upper bass due to time arrival difference at shorter wave lengths. Just an opinion, does not mean I am right. I was a sonar technician in the military and the acoustic properties and physics of sound energy is the same here. Good valid question, would be interested in what others think.
Yes. Multi sub is the answer here. The more Subs you have in the room the more the frequency response will balance and equalize. Of course placed in different places in the room which would mean that somewhere where there is a null from one sub, the other sub will fill in that null and thus create a proper frequency response . With DSP you further fix the peaks to be in line with the rest of frequency response and you get much more responsive sub frequencies in the room. 2 is huge upgrade over 1 and 4 is tremendous upgrade over 1.
Multiple subs do help but at what cost? I think using that money for treatment that can go that low is a more effective use of your money. A few db vs a lot (assuming you get the right treatment).
@@djhmax09 It is much... MUCH cheaper to put additional sub first then to treat the room. Room treatment for sub frequencies is a tedious and extremely complex job. It is not like for mid and high frequencies where you slap some panels on the first and second reflections and include some refracting panels...
Sometimes, the very low frequency peaks are in the room already without the system even playing, even when it appears very quiet. Environmental noise and parts of the building resonating in the wind etc. My little room plays about 30 something hz all by itself, I believe it’s the glass door resonating.
...And it starts getting interesting finding the best seating position fir the setup and then trying to widen the sweet spot best possible to more thsn one seat :) buts thats also an item for another video, right? :)
that is kind of a bass trap, that helps with peaks and dips, the problem that it need a large box volume and only works in that room for one narrow band of frequency, and presumably only work best in one spot in the room.
"Each band of the equalizer allows a maximum boost of “+6 dB” and a maximum cut of “-15 dB”. This asymmetrical setting range was chosen on purpose, as boosts of more than “+6 dB” are very rarely required. Every strong, narrow-band dip measured in the frequency response usually results from a cancellation caused by a phase shift. An equalizer typically cannot compensate for this, or only very inadequately, even if greater boosts were possible. Experience shows that you should focus on eliminating peaks in the frequency response. The human hearing reacts much more sensitively to narrow-band peaks than to narrow-band dips. " HELIX DSP user manual
you could get around this by increasing the whole output by 10db for example, this is done separately on the minidsp shd studio software, where gain for the whole channel is separate from the PEQ, and i have tried it out, you can get over 20db gain from this and i have not heard any artifacts from it. not like the free pc software called eq apo i used before, where as any boost was just everything else lowered, and creating quality loss if above 6 or 10 db in peq.
@@sudd3660 But keep in mind 0dB is full scale + dB means out of range, Helix recommends cut of instead of boost. I don't know how the minidsp does this.
with partial cancelation, a turning up can work. with full cancelation, it can't. some frequency dependant phase shifting dsp could work, but is likely distorting, noisy and has noticable latency
Some great information here thanks Paul, I do have a DSP question relating to dips in bass. In my case the dip is minor, I use mini dsp SHD preamp to give me a correction that I like. I admit to giving the correction a few db increase in the bass shelf also, just because I like it. My question relates to an example like mine. The dip in bass is minor, and so cannot cancel out the bass sound altogether. I’d imagine this is the more common experience? If so dsp could potentially help as I perceive it does for my tastes? What do you reckon as we aussies say? On the other point you make, dsp does flatten my somewhat peaky treble but I feel I loose some transparency or air to the sound. Is this what you are referring to with dsp on higher frequencies? I look forward to you addressing this question down the track. Keep up the great work! Tony W
The impression I got was that it’s pretty easy to control high frequency issues without using DSP, it doesn’t take too much in the way of room treatment and setup tinkering to get the mid and high to behave. And if you cheat and use DSP at those frequencies you might flatten the response but you still have the echo and reverb taking away all your detail and smearing your imaging and soundstage. In my opinion those two things matter a lot more than the actual high frequency response anyway. Cheers from QLD 👍🏻
Used to get this effect with transmission line speakers, the bass extension was very good but only made the dips very much more noticeable, had to get rid of them :( Didnt have dsp to sort the problem out either
You continue to talk about your new Loudspeaker book but it doesn’t seem to be available on either Amazon or the PS audio website. Is it yet to be released? If so, when? Also, a link to either site would be helpful.
Usually even with a subwoofer, there are only certain places you can put it considering furniture and how the room is designed. Thus the acoustically ideal location might not be feasible for other reasons. A few dB of a “dip” can still be DSP compensated but too much and you get clipping of the amp and/or the sub starts distorting at the amplified frequencies. With a DSP you therefore get much better placement options without causing a divorce.
@2:18 "Keep it in the bass. I'm fine with that. I like DSP for bass. No so big on the mid-range and tweeter." When you run the signal through a DSP box (or an equalizer), you are running the entire signal through that box. And that box acts as another pre-amp. That is active processing, and active processing is bad for sound quality. It adds distortion, coloration, and degrades the signal from what it was. You will be hearing that box, even if you keep all of its controls on their neutral setting. The only way to augment the bass, via DSP, without it touching the mids and highs, is to apply the DSP after a crossover -- and crossovers are the domain of speaker design. I know of no components that allow you to adjust the bass, while excluding the mids and highs. Also, for DSP to work, it has to use digital content. If you are playing a turntable, then its analog signal must be converted to digital to be processed, and then back to analog. The DS Process will act as yet another transport and DAC, and be subject to jitter. There is simply no way that that will leave your mids and highs as they were. Audio is an environment of compromise. If your bass problems are giving you agita, then DSP might be the proper remedy for you. But it is not a free lunch. Your mids and highs will change (assuming you have a revealing system). An alternative solution for correcting bass problems is what Vandersteen speakers (model Quatro and up) do. They have 11 potentiometers. With sound tuning equipment (microphone connected to a laptop with SPL (sound pressure level) software, you can measure each of 11 different bass frequencies, and adjust each one individually. The above keeps your signal 100% analog. It uses a high-pass filter for each channel. So it, too, will have an effect on the mids and highs. But Richard Vandersteen designed it all, and if you have heard his speakers, then you know that he knows his craft. The other advantage of the Quatros (and up) is that they relieve your main amps from 6 db of bass lifting, allowing your main amps to struggle less, resulting in cleaner mids and highs.
@@geddylee501 I would like to see Paul add a DSP box to his FR30 listening room, and leave the box on neutral. In other words, just add the DSP box to the signal chain. Then, I would like Paul to tell us whether or not he can hear when the DSP box is present, vs. when it is not present. Paul knows what his FR30 listening room sounds like. I am sure he will hear any change. I will lay 100 to 1 odds that he will hear it, and it will not be a struggle. I will also lay 100 to 1 odds that he will lose some texture, soundstaging, realism, etc, when the DSP box is in the signal chain. I am not suggesting that Paul is a proponent of DSP boxes. But he told his audience that he is okay with it in the bass, without telling them that there is no such thing as limiting its effects to only the bass.
you have some odd ideas how dsp are implemented and work, instead of picking are you points i could tell you this: for example add a digital dsp box, use it as preamp. into two dac's and stereo power amps, you have a mains pair of passive speakers and subwoofers with only drivers in a box. the dsp wont be noticed to degrade the sound for most people, and the benefits for those who hear it are worth it. think about what i said her, look at how many benefits this approach has. many companies make such digital dps boxed, minidsp shd studio or the flex model is two i know of.
@@sudd3660 "instead of picking are you points i could tell you this" Go ahead and pick. No matter how you use a DSP box, it becomes part of the signal chain. You will hear it. If you use it as a pre-amp, then you are limiting your sound quality to that DSP box's design. Perhaps there are some very good sounding DSP boxes. None of them show up a "Class 'A'" recommended in Stereophile or The Absolute Sound. For a mid-fidelity system, they are probably a good choice. But Paul does not tout his company as a mid fidelity audio manufacturer. He touts his company as high end. As such, he should caution that you cannot achieve that level of sound quality when you introduce a DSP box into your stereo. Surely a DSP box is a quicker fix than all of the room treatments that Paul has in his listening rooms. Yet, Paul does not use a DSP box. Although he has not said why, it is because his stereos will reveal the degraded sound quality from the DSP box. Your stereo is the sum off all of its boxes, and will never sound better than the worst box in the signal chain. "...and the benefits for those who hear it are worth it." In my initial comment, I wrote: "If your bass problems are giving you agita, then DSP might be the proper remedy for you. But it is not a free lunch. Your mids and highs will change (assuming you have a revealing system)." As to "the benefits for those who hear it are worth it", you can't know that. I can't know that. Only the person that tests it, with their stereo, in their room, can know that. A DSP fix should be for those that are not seeking the best sound quality possible within their budget, or people that do not have time to make room adjustments to fix sound issues, or people that are physically unable to do so. If you can fix sound issues, passively, that will almost always sound better than using a DSP box. I write "almost always", because if a room has severe issues, then a DSP box might be the only way to fix those issues, and that fix might be worth trading off a bit of sound quality. A DSP fix should never be choice #1, when seeking the best sound quality.
It's not what I felt : less output at room mode frequencies (very high factor Q) equals to less reverberation time. Even if the gradient might be the same, the output a RT0 and RT60 is lower and «analogue», sorry, analogous to other frequencies except cancellations.
I never understood the whole DSP angle. There’s nothing like a well constructed listening room. Isn’t DSP correction predicated on mic placement anyway?
DSP correction can be done against listening tests or measurements or both. Best is to do it against both and only after you have done best effort on speaker placement and room acoustics making the DSP correction do its thing with minimum tweaking. Also, DSP correction is great only for a subwoofer or on music that is already digital at the matching sample rate of the music.
@@ThinkingBetter Right, well then in that case, why not just forego the added complication and expensive having it ? Audiophile equipment is out of financial range for many as it is, but that said, I suppose there will always be the few that have the means and want the extra capability in spite of its limited effectiveness. You could argue that a listener with a compromised space may need it more, but with limited effectiveness in a compromised situation, why bother paying for it if it won’t save the day anyway lol
@@shipsahoy1793 DSP correction can do amazing improvements even after careful system optimization using placement and room treatment. Actually it's not really possible to make a very precise performance just by doing room treatment and speaker placement only. Then comes the speakers performance itself and your preferred tonal balance.
@@ThinkingBetter OK well now it sounds like you’re selling the idea.. in your previous post you made it sound like it’s effectiveness was limited but now it seems like you’re singing a different tune so to speak but that’s OK whatever; I personally don’t need to get involved in the dsp, especially at my age; I probably hust don’t care lol but I always like to hear about what’s going on in the technical world, and try picking up a few things here and there. Sometimes getting another perspective can modify your own; there’s lots of teachable moments all throughout life.🥳✌️
@@shipsahoy1793 There is one EQ calibration that I’ve found very useful. I call it rejuvenation EQ and the idea is to boost the very highest treble making you recover hearing some of the fine details in that region. Imagine you have lost 6dB of sensitivity at 12kHz due to aging. By adding 6dB back again through EQ, you get closer to how it sounded like before.
you know how to insult people naively/gently😂 it is very simple you get a single driver cabinet that can cover a frequency range from 660 Hz down to 20Hz, with a DSP with delay connect up the speaker and flip the phase and add the correct delay, this can be done in rew what is free! just need a universal calibrated usb mic about $30. place in the middle of the two forward speakers ideally on a stand behind the listener or on the wall behind facing your main speakers. this will give room correction and take away the dips in frequency below 660 Hz where you get comb effect happening that's what you're getting by having dips and you do not need to push the speakers so loud so you don't encourage peaks.
that is a gross oversimplification, dsp adjust volume of those room modes, technically they are not fixed but less of a problem and therefore you get better sound quality. but also dsp is a wide term, with dsp you can also adjust pahce and delay, that could actually fix room things, a null could be adjusted for.
