YAMAHA NS-1000M SPECS
| Frequency Response: | 40 – 20,000Hz |
| Sensitivity: | 90dB (1W input, measured at 1m) |
| Impedance: | 8Ω |
| Power Capacity: | 100W (continuous program) |
| High Frequency Driver: | JA0513 30mm (1.2″) Beryllium Dome |
| Medium Frequency Driver: | JA0801 88mm (3.5″) Beryllium Dome |
| Low Frequency Driver: | JA3055A 300mm (12″) Paper Diaphragm |
| Crossover Frequencies: | 500Hz & 6,000Hz |
| Enclosure Type: | Closed |
| Enclosure Dimensions (HxWxD): | 675x375x326mm (26.5×14.75×12.75″) |
| Weight: | 31kg (each speaker) |
| Production Year: | 1974 |
| Price When Launched: | £340 for a pair |
| Equivalent Present Day Price: | £3,700 for a pair |
| Current UK Price: | £600 to £1,500 for a pair |
88mm dome ... what a beast
i would love to see its THD vs SPL
Anyway i have two of these quite old Vintage ITT lpkm/105/37/120
i wonder if they are of any value I liked the little lens
German domes look quite well built usually
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Yes, that SEL/ITT 50mm dome is very nice. Looking at its cross-sectional diagram in Martin Colloms, it is rather obvious the ATC 75 mm dome mid is -albeit larger- to a large degree based upon the SEL/ITT design with its double suspension and pseudo waveguide.
Got it, thanks. So basically optimising for sound power over vertical listening window width.
Not wanting to go too far off-topic but for those like me who were curious this might help.
Quick sim of two 100mm drivers (could be 100mm mid-bass with tweeter in 100mm waveguide). 3 KHz LR-24 xover.
Driver spacing of 100mm (0.9x 3KHz wavelength) gives us a -6dB point in the vertical axis occurring at 23 degrees.
Driver spacing of 135mm (1.2x wavelength) gives us a -6dB point in the vertical axis at 15 degrees.
The 'black hole' in the polar response with 135mm spacing is closer to the listing axis, but on the other hand is less pronounced than with 100mm spacing. Depending how we weight the directivity index, either one might looks better than the other.
Hi thank you very much for the very kind and valuable advice
Therefore I will keep it with care
The conditions are to be checked being a very old unit
Therefore I will keep it with care
The conditions are to be checked being a very old unit
That's exactly the point - control the vertical off axis null so it is not in the ceiling and floor reflections.
This works for a "standard" listening position and shows better in room response when you calculate with these angles for the reflection. But when you have a different listening situation or a bigger listening area ... or even different listening heights ...
So I prefer to do room acoustics and put chassis as close together as possible. I routed the front baffle of the MD60 to get closer.
But my background is prefessional listening. Good rooms and also close listening distances, somtimes also listening in standing position. That's often not the case in an average living room, there a bigger distance can be beneficial.
And I am also a coax fan, close drivers get closer to that experience.
That ITT dome mid is very good. We used it often in the 80s for 3 way projects with the Audax TW025A0 soft dome and an 8" or 10" Heco woofer in acoustic suspension box. Those older 2" soft domes were good at playing back orchestral band and jazz. Philips, Heco and LPG also sold some nice mid domes back in the day. The Audax mates well with them, but tends to get a little muddled with louder, more complex and heavy brass sections. Some of the Seas tweeters performed better, but cost more. The Vifa D25AG35 was one of the best alloy domes available at a reasonable price back in the day. It blended very well with most dome mids, even the D7608.
The ITT dome mid performed well with complex, dynamic music. A decently behaved metal dome will mate very well with it, conveying the more dynamic and harmonically weighted material.
Not considering off axis response alone, while you can get away with crossing a 2" soft dome mid like the ITT higher than 5k to a soft dome tweeter, don't be tempted to cross the same mid much higher than 4k to a refined and metal dome. That usually makes the sudden jump in harmonic character more pronounced at the point the mid hands over to the tweeter, even if you discount the off axis behavior of both drivers. The mid won't be as detailed / clean despite what it's FR is leading you to believe. The linear response fools you into thinking its is still playing clean, but you're almost at the 2" mid's natural breakup mode at roughly 6 kHz, when the tighter and more present sounding metal dome is just taking over. That sudden shift in the harmonic balance will ruin continuity and draw negativr attention to itself. That spoils the entire tonal character of the speaker
Crossing higher to most soft dome tweeters isn't so critical because the tweeter is already starting to play in partial breakup mode and won't shift the overall acoustic character as drastically.
Most of the time you don't want to blend diaphragm types between mids and tweeters, but it depends on the type of cloth and surface treatment used on both the mid and tweeter. You can even mate a planar tweeter to a soft dome mid if the crossover point is carefully chosen, mainly due to the narrow vertical pattern most planars.
The ITT dome mid performed well with complex, dynamic music. A decently behaved metal dome will mate very well with it, conveying the more dynamic and harmonically weighted material.
Not considering off axis response alone, while you can get away with crossing a 2" soft dome mid like the ITT higher than 5k to a soft dome tweeter, don't be tempted to cross the same mid much higher than 4k to a refined and metal dome. That usually makes the sudden jump in harmonic character more pronounced at the point the mid hands over to the tweeter, even if you discount the off axis behavior of both drivers. The mid won't be as detailed / clean despite what it's FR is leading you to believe. The linear response fools you into thinking its is still playing clean, but you're almost at the 2" mid's natural breakup mode at roughly 6 kHz, when the tighter and more present sounding metal dome is just taking over. That sudden shift in the harmonic balance will ruin continuity and draw negativr attention to itself. That spoils the entire tonal character of the speaker
Crossing higher to most soft dome tweeters isn't so critical because the tweeter is already starting to play in partial breakup mode and won't shift the overall acoustic character as drastically.
Most of the time you don't want to blend diaphragm types between mids and tweeters, but it depends on the type of cloth and surface treatment used on both the mid and tweeter. You can even mate a planar tweeter to a soft dome mid if the crossover point is carefully chosen, mainly due to the narrow vertical pattern most planars.
I grew up being taught that the diaphragm of a driver should behave like a piston Then i look at the pistons and I don't see many "soft" pistons
(by the way they are all made out of some aluminum alloy)
So I wonder how can a soft dome behave like a piston? It seems impossible to me
Probably and as usual I'm missing something
(by the way they are all made out of some aluminum alloy)
So I wonder how can a soft dome behave like a piston? It seems impossible to me
Probably and as usual I'm missing something
Hi @ginetto61
No diaphragm behaves like a piston in all situations. There will be all sorts of non-pistonic behaviours, mostly in the upper frequency region (break-up).
Hard materials behave like pistons up to a certain frequency and then often break up quite violently.
Soft materials have more gradual and dampened break-up behaviour. That can be advantageous and/or make dealing with breakup simpler.
No diaphragm behaves like a piston in all situations. There will be all sorts of non-pistonic behaviours, mostly in the upper frequency region (break-up).
Hard materials behave like pistons up to a certain frequency and then often break up quite violently.
Soft materials have more gradual and dampened break-up behaviour. That can be advantageous and/or make dealing with breakup simpler.
Hi thank you so much for your kind and helpful advice
Sometimes some basic questions can sound provocative
What i mean is that if the pistonic behaviour is the goal soft membranes are out of the game for their intrinsic mechanical properties
About break-ups of course that is a very likely issue But digital filters can be made with huge slope and precision
So the rigid membrane will work only across is optimal range
Passive filters could be out of the game as well Just send a SW signal in and see what you get out on a scope
About soft domes 🙂 many years ago at an audio fair i heard a faboulous sound out of a soft dome in an Acapella speaker But it was horn loaded The sound even move me
It was a choir Sublime I think it was the Violon model
https://audiofederation.com/brands/acapella-audio-arts/acapella-price-list
Sometimes some basic questions can sound provocative
What i mean is that if the pistonic behaviour is the goal soft membranes are out of the game for their intrinsic mechanical properties
About break-ups of course that is a very likely issue But digital filters can be made with huge slope and precision
So the rigid membrane will work only across is optimal range
Passive filters could be out of the game as well Just send a SW signal in and see what you get out on a scope
About soft domes 🙂 many years ago at an audio fair i heard a faboulous sound out of a soft dome in an Acapella speaker But it was horn loaded The sound even move me
It was a choir Sublime I think it was the Violon model
https://audiofederation.com/brands/acapella-audio-arts/acapella-price-list
the choir was really amazing ... perfect The bass i prefer not to comment Completely detached from the sublime mids and highs like in some early Avantgarde speakers Bass is difficult Very difficult
The word 'soft' is a bit miss-leading. The diaphragm is not behaving like a soft material in a lot of the frequency range, it does behave like a piston. This is due largely to the geometry. It is just softer than metal or paper. Metal is also 'soft' at a certain frequency because EVERYTHING is elastic under certian conditions. As always there is a trade-off between pistonic frequency bandwidth and behaviour outside that range.
Hi thanks a lot for the very interesting advice
Now it's more clear
As always distortion measurements will tell the truth
Now it's more clear
As always distortion measurements will tell the truth
You also can look at off axis behaviour to estimate the piston behaviour of a membrane. A perfect piston has a distinct off axis behaviour - soft domes often react differently. At lower frequencies they behave like a piston, maybe with higher mechanical losses.
These metal membranes are also just thin foils, they are less rigid as it seems.
After all it's about the sound. Many people don't want to hear every dirty detail of the recordings - soft domes often add something to the sound what people like. When searching for the "truth" I would always start with hard domes and stay away from break up area generously. (I also prefer tweeters with resonances far from 20kHz - not exactly sure why but this experience repeats.)
These metal membranes are also just thin foils, they are less rigid as it seems.
After all it's about the sound. Many people don't want to hear every dirty detail of the recordings - soft domes often add something to the sound what people like. When searching for the "truth" I would always start with hard domes and stay away from break up area generously. (I also prefer tweeters with resonances far from 20kHz - not exactly sure why but this experience repeats.)
In a complicated sequence of events I've managed to do some trading of unused drivers for a pair of M74As. I already have T34Bs, so these should pair up very well with the M74As. I'm still going to use the other D7608s in conjunction with the M74As to push the xover down to about 400 hz by placing the D7608s around one of the M74A per side while leaving room for the T34B just above it. The power to the D7608s will be tapered and driven from 400 hz upwards, LP of 900 on all 4 of the D7608s. This will relieve the M74A of some lower mids but still make the group of mids act like one larger driver. I've done this using 5 x MDM55s and SB29RDNC with excellent results. The polar pattern was the same as a 6 inch driver but with a 5k upper limit. Circular arrays can work well if they're done right. This time I'll need to do more documentation for this thread using the D7608s in this same manner.
the truth, the whole truth, and nothing but the truth
This what High fidelity is about
Low distortion is much more important than sounds
Human senses are deceiving
Humans are limited by nature
I can't hear above 13 KHz for instance And just with clean ears
Can you?
This what High fidelity is about
Low distortion is much more important than sounds
Human senses are deceiving
Humans are limited by nature
I can't hear above 13 KHz for instance And just with clean ears
Can you?
I don't quite understand the context of your question. Are you just asking whether I can hear past 13k? In that case, yes I can hear to about 15k flat on a good day, but that's not really anything I'd consider being an influence of accuracy, unless the treble is boosted to sound more intelligible.
In all reality and sincerity, its more important the midrange of 300 hz to 10 k is represented with flat phase and magnitude, but the loudness compensation curve applies depending on absolute volume level of playback to determine what actually "sounds" flat. The dip at 2.5 - 4 k in our hearing sensitivity is something which varies from person to person and needs to be considered when adjusting EQ. Absolute flat response isn't actually interpreted as such to the ear and you'd need to carefully adjust the amount of dip applied to the midrange curve.
Some people claim the so called Harman curve sounds pleasant, with its gradually declining amplitude towards the top, but its not perceived as flat by the ear. I'd say it's merely "pleasant" or polite sounding for passive background music listening. Its not an applicable EQ curve for calibrating accurate playback of music ie. for the sake of monitoring a recording or for editing purposes. Proximity to the speakers also makes a difference in tonal balance, as the low end will fall off at a different rate compared to the top end.
Live recordings also need a slight top end lift to sound accurate, depending on the micing technique used. For example, binaural stereo recordings need about 1.5 dB per decade lift towards the top of the curve. Again, it varies and depends on several factors how much compensation is required to sound right to most people.
In all reality and sincerity, its more important the midrange of 300 hz to 10 k is represented with flat phase and magnitude, but the loudness compensation curve applies depending on absolute volume level of playback to determine what actually "sounds" flat. The dip at 2.5 - 4 k in our hearing sensitivity is something which varies from person to person and needs to be considered when adjusting EQ. Absolute flat response isn't actually interpreted as such to the ear and you'd need to carefully adjust the amount of dip applied to the midrange curve.
Some people claim the so called Harman curve sounds pleasant, with its gradually declining amplitude towards the top, but its not perceived as flat by the ear. I'd say it's merely "pleasant" or polite sounding for passive background music listening. Its not an applicable EQ curve for calibrating accurate playback of music ie. for the sake of monitoring a recording or for editing purposes. Proximity to the speakers also makes a difference in tonal balance, as the low end will fall off at a different rate compared to the top end.
Live recordings also need a slight top end lift to sound accurate, depending on the micing technique used. For example, binaural stereo recordings need about 1.5 dB per decade lift towards the top of the curve. Again, it varies and depends on several factors how much compensation is required to sound right to most people.
When you have an on axis linear speaker with controlled off axis behaviour (slightly rising DI) in a neutral room - you get something similar to the Harman curve as in room sound.
With for e.g. DIRAC you can play around with in room goal curves and compare. I prefer a little less tilting as Harman in my living room (but have speaker with high directivity - less HF in the room) and linear in my studio room (close listening, very controlled room). Which is about the same what the speaker is doing.
Back to topic - looking forward what you think about the Bliesmas. What do you use as LF drivers?
I also have a few drivers around I would switch for Bliesmas ... 🤓
With for e.g. DIRAC you can play around with in room goal curves and compare. I prefer a little less tilting as Harman in my living room (but have speaker with high directivity - less HF in the room) and linear in my studio room (close listening, very controlled room). Which is about the same what the speaker is doing.
Back to topic - looking forward what you think about the Bliesmas. What do you use as LF drivers?
I also have a few drivers around I would switch for Bliesmas ... 🤓
@IamJF I'm using 2x B&C 8NDL51 per side. So far they're one of the overall best 8" midbass I've heard and used. They have a very detailed but well behaved sound. Woofers are 2x SB34NRXL75.
I understand the results you're getting in room with your measurements. My only deviation is the slight 2.5 - 5 k dip which I see every time on any of the typical builds. I've already heard a few of the Bliesma mids and tweeters. The M74A was always on my radar as was the T34B. I would have preferred the T25B, but I wanted to cross the tweeter a little lower depending on the M74A.
I understand the results you're getting in room with your measurements. My only deviation is the slight 2.5 - 5 k dip which I see every time on any of the typical builds. I've already heard a few of the Bliesma mids and tweeters. The M74A was always on my radar as was the T34B. I would have preferred the T25B, but I wanted to cross the tweeter a little lower depending on the M74A.
You could give a try to use the SB34 up to 400Hz when the housing is allowing it. That's easy for them.
I also plan 4-way for high quality reproduction but with the right components and setup in the room I can reduce to 3-way. Less crossover is always good to have when you don't have to compromise other properties.
For very high SPL the T34 is the way to go. I cross the T25B at 2kHz active 4th order, but for "normal" listening levels. They will burn before showing big amounts of THD (you can't do a automated 1%THD max level measurement, the tweeter doesn't reach 1% in some frequency areas!), so not a failsave setup.
Looking forward to your results!
I also plan 4-way for high quality reproduction but with the right components and setup in the room I can reduce to 3-way. Less crossover is always good to have when you don't have to compromise other properties.
For very high SPL the T34 is the way to go. I cross the T25B at 2kHz active 4th order, but for "normal" listening levels. They will burn before showing big amounts of THD (you can't do a automated 1%THD max level measurement, the tweeter doesn't reach 1% in some frequency areas!), so not a failsave setup.
Looking forward to your results!
Looks like they made it this time without incident. Should be a good combination with the T34B. It definitely needs a -10dB notch centered at 11k with medium Q. They are very compact which is a major advantage crossing them with a shallow LP / HP to tweeter. I dont like anything steeper than 2nd order LR electrical.
I'm pretty set on using the 8NDL51s as MB. They are a bit more resolving than the SB12s when crossing at 500 - 600 Hz, not to mention have more flexible directivity control with 2 x smaller midbass drivers. The goal is unrestricted dynamic range in a reasonable package. I have lots of options with these drivers. I also want to take advantage of the 95+ dB sensitivity having mid and tweeter domes with that kind of efficiency.
I'm pretty set on using the 8NDL51s as MB. They are a bit more resolving than the SB12s when crossing at 500 - 600 Hz, not to mention have more flexible directivity control with 2 x smaller midbass drivers. The goal is unrestricted dynamic range in a reasonable package. I have lots of options with these drivers. I also want to take advantage of the 95+ dB sensitivity having mid and tweeter domes with that kind of efficiency.
Attachments
For my 4-ways isobaric project, I finally placed an order for a pair of SBAcoustics SATORI MD60N-6 :
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