As Leonardo says "Dont Look Up"
And hence I posted the simulation of the 18 inch bass driver in a sealed box, also explained in a following post a brief explanation of why sealed box/ time domain accuracy is superior to any port/TL/delayed resonance system... As James says "Its hard to fill a glass that is already full" and clearly Tim your cup is overflowing...😉
Now now Tim, dont you know what it means when one person in a debate resorts to name calling?😢
Sorry Tim, but I specifically chose and pointed out that both PHL and the Celestion drivers should be used to cover the 300Hz to 2Khz band... Thats not bass, thats the critical midrange where vocals are reproduced and the human ear is astonishingly accurate in detecting any form of distortion, esp time domain / ghost echo distortions which plague high high Xmax/high cone travel designs.
Hey now you are catching on....😉
Ahaaw, just as I you got my hopes up 🙂 you slip back into "more cone travel is better mode"... My point was and remains, that at any frequency from low bass to highs will be reproduced far more accurately when (a) The cone travel of the driver(s) is minimized and (b) the driver(s) are loaded in a sealed box.
Damn, that Celestion is one sweet driver when used as I suggest ie sealed box covering 300Hz to 2Khz or maybe 3Khz. But its still only 5 inch driver and the 6inch or 6.5 inch drivers are way better... Why is bigger better in this case? Here is why:
Becausea pair of the 6.5 inch PHL drivers will hit your 100dB in room SPL with under 0.25mm (!) of cone travel and do this with just 4 watts in a 3 litre sealed box!! If you dont understand the significance and fundamental advantages of this... Well as I said earlier, I am happy with that situation.
My document holder is now stationary... Sorry, I rest my case.
The advantages are:
(1) High efficiency (really we should refer to high sensitivity as even PA drivers are only about 2% to 6% efficient at turning electrical energy/watts into sound energy) drivers allow you to use low power to reach high SPL. This reduces or eliminates all forms of thermal distortions and increases long term reliability/performance.
(2) Most PA drivers use stiffer suspensions / higher Fs linen/cotton/fabric surrounds and spiders instead of rubber surrounds. This is vital as it greatly reduces the "Mass on a Spring" resonance issues (ghost echoes) which plague rubber surround drivers. This is a complex and controversial subject so I dont want to kick the wasp nest any more 🤣... But happy to discuss if you dont mind drifting off topic too much?
(3) PA drivers tend to use light(er) weight paper cones ie low Mms and powerful motors (high Bl) which maintains more control/tighter grip of the cone. This again helps reduce "ghost echoes" or unwanted resonance.
Troels is a subjectivist interested in trying all sorts of things related to loudspeakers. PA drivers tend to be big, loud and efficient but this comes at a price in terms of resonant cone motion which is audible but not necessarily unpleasantly so.
If you are seeking guidance on what is required for high technical sound quality (rather than high subjective audiophile sound quality which is a perfectly valid objective but a different one) then I would suggest looking at midfield studio monitors from the larger established manufacturers. They don't use PA drivers but they also don't use small low efficiency home audio drivers either but something in between. The reasoning being something like gaining the benefits of high efficiency without the audibly resonant cones. They also give a lot of attention to controlling directivity.
He probably got bored using hifi drivers. The 15PR400 he uses isn’t that special. Typical rather short coil (15mm) and gap of 10,5mm leads to mediocre Xmax (we could of course discuss the calculation of Xmax alone…). The trade-off to high efficiency in this case might well be compression on low frequencies. I don’t know why one would pick such a driver for home use other than it might be fashionable. Troels uses long stroke BMS drivers too IIRC, that makes more sense, but all in all it boils down to picking the right (pro) driver.
Hi forum!
I have one point in the discussion for a comment hoping that Lehnok don't get too confused with all this different opinions here. In the last years the more innovative development shifted from HiFi to PA. If you look at the engineering know-how spent from companies like Eighteensound for the PA sector, the only comparable development effort in the HiFi drivers sector maybe the Ellipticor stuff of Scan-Speak, with very very high prices.
I have one point in the discussion for a comment hoping that Lehnok don't get too confused with all this different opinions here. In the last years the more innovative development shifted from HiFi to PA. If you look at the engineering know-how spent from companies like Eighteensound for the PA sector, the only comparable development effort in the HiFi drivers sector maybe the Ellipticor stuff of Scan-Speak, with very very high prices.
@SBA_SLOB_GUY
Interesting.
Perhaps I’ve been away from PA developments for too long (for family reasons 2009-2016 were a bit blurry for me)
What innovations have occurred in speakers designed for the PA market?
I’m looking for lightweight drivers with neo motors, 10”-12” cone size, 12mm or more x-max and sub 30Hz Fs. Do you know of one?
To @Lehnok
Have you considered 18Sound 6ND430. Comes in 4, 8 and 16 ohm varieties. At 6” in size, can easily slip between your 18” and 2” drivers. Nice and smooth frequency response, good inductance control and low harmonic distortion. Works well between 100Hz and 2KHz.
Interesting.
Perhaps I’ve been away from PA developments for too long (for family reasons 2009-2016 were a bit blurry for me)
What innovations have occurred in speakers designed for the PA market?
I’m looking for lightweight drivers with neo motors, 10”-12” cone size, 12mm or more x-max and sub 30Hz Fs. Do you know of one?
To @Lehnok
Have you considered 18Sound 6ND430. Comes in 4, 8 and 16 ohm varieties. At 6” in size, can easily slip between your 18” and 2” drivers. Nice and smooth frequency response, good inductance control and low harmonic distortion. Works well between 100Hz and 2KHz.
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Back in the early 90s you already could build a nice 2-way with a Beyma 15K200 and CP350 with TD435 IIRC. Probably did a better job than quite a few of Troels’ recent designs… decent directivity behavior, good max SPL and likewise distortion. So what’s new…
The big gains the last decades IMHO lie in directivity control and low frequency response control. Both are hardly driver dependent.
The big gains the last decades IMHO lie in directivity control and low frequency response control. Both are hardly driver dependent.
Good suggestion Andy, I heard a pair of these in a well treated room https://www.soundonsound.com/reviews/psi-a21-m and they did sound good at mid to high SPL, but they were a bit grey and flat at low SPL, but great for mixing / mastering engineers.
I have also heard these at a London dealer ( not a well treated room) https://www.soundonsound.com/reviews/neumann-kh120-ii and standing in the sweet spot they were... Sweet!
A great DSP with both digital in and analog in is the DBX https://www.aliexpress.com/item/1005004859423877.html for £450. landed in UK
Or if you really want to go super high end an extra £1,000 gets you a https://linea-research.co.uk/asc48/ and your your own DAC's.
Add drivers and cabinet and you are good to go!
Yes I like the B&C 18 and 21". As well as Eminence NSW 18 and 21". And all the 1ohm drive IPAL models are useful too.
But where are the 10-12" with that kind of excursion and neo motors? You know, trickle down to us mere mortals who play at home to only 1-3 people, not outdoors to 300+ people.
But where are the 10-12" with that kind of excursion and neo motors? You know, trickle down to us mere mortals who play at home to only 1-3 people, not outdoors to 300+ people.
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Those appear to be mainly small monitors for sitting near at a mixing desk. Midfield monitors are typically 3 ways with 12" monitors suitable for use in rooms rather than at desks. So the same as for home audio but with a stronger emphasis on technical sound quality rather than the many other requirements home audio speakers tend to address.
Lehnok
I think you should be clear about your goals and intentions. Otherwise you will get very contradicting advice.- What size of room do you plan to sound? Home or pro application?
- What level of sound quality would you like to achieve?
- What kind of DAC and amps are you planning to connect?
Alex, speakers with moving coils generally have distortion modes caused (among others) by inductance variation as they move relative to the imperfectly saturated magnet poles.
There are 2 main ways to linearise that effect and reduce IMD from it: adding series resistance or series inductance, or using a current amplifier like an active impedance with a voltage amplifier on its input. Even copper shorting rings can only do so much, because they add a mechanical load, which has to be balanced against things like Qms not being too low and a clean waterfall plot.
There's also the tendency for microphonic voltages from cone resonances and box vibrations to be shorted out by a directly-coupled amplifier. So they get converted into current. So a voltage amplifier with as-low-as-possible output impedance may seem appealing because it looks a little bit like servo control, but with the lag and built-in non-linearity it just adds distortion and resonances at mid-range and high frequencies.
Careful design of passive XOs tries to take those things into account, and if the speakers also end up well EQ'd then that's a bonus, not the main point. Combining active and passive techniques could be as simple as using DSP together with air cored inductors for the woofers, and generous padding resistors for tweeters.
Hi gaga_r,
My listing/HT room is 32 SQM. Well damped. Listening position ~3m . Exclusively digital sources. Chord DAC and Burson pre. I have 4ch icepower1200 and stereo Purifi at the moment.
In recent years, due to frequent relocations and limited bookshelf space, I had to choose smaller-sized speakers like KEF, Harbeth, and B&W. However I am a sucker for big speakers. I've listened to big Harbeths at a dealers and I loved them. On the other side of spectrum I also very much liked JTR at my friend's place. Very impressive. So the design goal was a big impactful sound for both music and HT.
Cheers,
Konrad
Thanks abstract,
I am certainly not able to carefully or even (basically!) design a passive crossover but I have Eq'd a lot of systems in a lot of rooms and even a few basic speaker measurements in room are enough to pretty much transform a poor sound into good or even very good.
The passive crossover does act as a "lowest common denominator though as you have to balance and voice the speaker down to the least efficient driver.
In my own system I run 250 watt class A/B on the bass and 8 watt SET for mids and top.... Any passive crossover is a no no for me, but I agree with you, for some it could work.
Cheers
A.
I am certainly not able to carefully or even (basically!) design a passive crossover but I have Eq'd a lot of systems in a lot of rooms and even a few basic speaker measurements in room are enough to pretty much transform a poor sound into good or even very good.
The passive crossover does act as a "lowest common denominator though as you have to balance and voice the speaker down to the least efficient driver.
In my own system I run 250 watt class A/B on the bass and 8 watt SET for mids and top.... Any passive crossover is a no no for me, but I agree with you, for some it could work.
Cheers
A.
Lehnok
I'm a bit confused, on the one hand, JTR is a simpler speaker, with high sensitivity and has an impactful but less detailed sound character.On the other hand, the Harbeth is old school, has its own cool sound style, great at unlocking its potential with good powerful amplification. Clearly heading towards the high end.
The Chord DAC and Burson pre, the set of speakers you bought, and the mention of B&W says that you are aiming for a better sound after all. So you can get it.
And so, in addition to your drivers, you can take the following midbass:
- Accuton C220-6-222 CERAMIC BASS-MIDRANGE.
- B&C 8NDL64-8 or something like this
I see two directions for the development of the project:
1st, simpler, both in sound and in setup.
DSP crossover, your amplifiers (3-way is enough) + coil for mid and capacitor + lpad for tweeter. The payoff is the simplicity of the setup. Don't forget to set limiters for all bands, otherwise there is a risk of burning the drivers. But in this case you do not fully unleash the full possible potential of your drivers and Chord DAC and Burson pre.The 2nd, more complicated and time-consuming to make, but gives the highest quality sound of the ultimative high end level.
- Analog active crossover (must be purchased) (like Bryston 10B electronic crossover or FM acoustic or Sublime K231 Stereo 3-Way Active Crossover etc.) + coil for mid and capacitor + Lpad for tweeter.
- icepower1200 for sub and midbass bands (but prefers class A or A/B amplifier for midbass, the same as for the mid-tweeter band. Up to you)
- a good class A or A/B amplifier (must be purchased) for mid-tweeter.
In any case, I advise you to first calculate and make a test box for midbass and start stitching with midbass - mid (not mid-tweeter). And then, when you have already achieved a perfect seamless midbass - mid joint, to add tweeter and sub to them.
Sub 18 inch in ported box about 140L.
Midbass 8 inch in sealed box 12-15L
The midbass-mid-tweeter elements should be placed as close to each other as possible.
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I've been saying this, and doing it, for about 20y, since I got hold of my first decent DSP.
I actually built a system once like this, 3 way 15/10/1 set the gains roughly without measuring (but I had calced out the gain structure beforehand) set the xover points where I knew they'd be OK based upon earlier driver measurements, and had the system sounding very good in minutes. It was improved with final measurements later and subsequent adjustments, but they only added a few %, not a massive veil lifting, wife running in from an adjacent room difference. And I did it in front of an unbelieving, very sceptical witness, but this was far from my first rodeo.
Yeah, nah.
BTW When using DSP you will need to play with delay when watching HT otherwise you will have video out of sync
Depends on the needs of the app and ones POV re speaker design and IME the pioneer's is superior overall. 😉
Anyway, I'm not aware of any pioneer (4) way cone/dome speakers, but considering the woofer's recommended BW only being rated to 200 Hz combined with the desire to have more life-like lower mids it seemed the best way to design it, not to mention it assures good polar response matchups, at least one of the main reasons for using octave spreads AFAIK. 😉
As for XOs, they used mechanical XOs for wide range single drivers and either autoformers, none or 1st or 2nd order 'textbook' combinations for the rest and of course they designed/made drivers to suit, so obviously one needs to carefully choose the right drivers nowadays if wanting to keep it simple as practical.
Last, but not least, they needed high efficiency due to minimal Xmax, available power at reasonable prices and the need for low distortion at the high SPLs required for high speech intelligibility in large venues, which glad to see the thread has recently zero'd in on its importance, so all things considered still an excellent way to design for best overall performance. 😉