Building a 3-way TL speaker
- Thread starter Hari Iyer
- Start date
keith_correa
Well-Known Member
Then use this ring radiator - Peerless XT25TG30-04.
If you are looking for a wide band tweeter with good power handling, the ScanSpeak Illuminator R series is very good.
ScanSpeak Illuminator
ScanSpeak Illuminator
Decadent_Spectre
Well-Known Member
Might I humbly suggest -
www.bmsspeakers.com
www.bmsspeakers.com
Coaxial Compression Drivers
www.bmsspeakers.com
Coaxial Compression Drivers
www.bmsspeakers.com
kapvin
Well-Known Member
4 way will be a nightmare to align even with first order crossovers. and there will be significant loving issues with using a crossover at 8k. would be much simpler to import the beymas and pay the duty.
I may go 2nd order or probably 3rd order after measurement. Not sure how much lobing will affect as the CD will be in a horn. Will plan a horn for the fountek too if i go that route. beymas dont seem to available to import too - i have checked that possibility. import cost is staggeringly high with one site - shipping is the killer.
Kannan, thanks for sharing, the peak above 15KHz is a point to consider which looks annoying at the moment. The phase plug on top of the dome could be a source of resonance though i am not sure.
Keith, thanks for suggesting. Somehow Peerless drivers never got adjusted with me so pass it this time.
Decadent_Spectre, thanks for your suggestion. Will have a look at them and decide appropriately.Might I humbly suggest -
Coaxial Compression Drivers
Coaxial Compression Drivers
Finally after lots of research and combinations ordered the SB Acoustics, Satori Beryllium tweeters. They should be delivered soon as they are on stock with the dealer. Inital simulation showed they matched quite well with the Satori mid-range.
M
mpw
Guest
Hair
In the satori midbass there is a dip in response at @1500 Hz..
How is this being tackled ?
In the satori midbass there is a dip in response at @1500 Hz..
How is this being tackled ?
mpw, i had done a NF measurement of the satori and i found 1120Hz and not at 1.5kHz as dip as per my microphone. This was measured with the microphone almost touching the dust cap. I won't worry too much about that if i am not able to measure at 1 meter or the far field listening position.
M
mpw
Guest
While I have looked at different satori designs especially at Troelsgravesen...I find this dip a bit disconcerting...
Maybe I am not in the same league as you perhaps in speaker building..
Ideally u want to hear everything...than not hear something which the mic doesn't pickup..
Did u try a test time say from 1khz to 1.5 kHz slow sweep ?
Maybe I am not in the same league as you perhaps in speaker building..
Ideally u want to hear everything...than not hear something which the mic doesn't pickup..
Did u try a test time say from 1khz to 1.5 kHz slow sweep ?
keith_correa
Well-Known Member
Check this out:
Is it an optical illusion or does the tweeter baffle angle outwards?
Also, that step under the tweeter is bound to create diffraction - let's hope it's not nasty.
Is it an optical illusion or does the tweeter baffle angle outwards?
Also, that step under the tweeter is bound to create diffraction - let's hope it's not nasty.
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Thanks for your insights, i shall check the Troelsgravesen article to know more. IMO, mic will pick up anomalies better than my ears and so a slow sweep won't help much in my case to find out issues. I think its the peaks that we need to worry much than the dips in the response.
Keith, its not an optical illusion, i have tried to align the mids and the tweeter in time at the VC centers.
I shall be crossing the tweeter around 2KHz. The baffle step @ 2KHz starts from around 2.27 inches and the slope is beyond that range, so not expecting them to interfere at the cross-over point. I will be more worried about that step for the midrange driver as its within its range for a bump. Only after i measure them i will be able to know how to address it. The slope is around 4" from the mid-range center and that translates to 1130Hz. I need to discover if that helps me to counter the dip in the mid-range at that frequency.
M
mpw
Guest
fyi.. Troelsgravesen charges about Euro 100 per pair of midbass to apply some coating which apparently smoothens the response at that freq..
M
mpw
Guest
Troelsgravesen doesnt suffer fools - it is quite evident from his website and his attitude.. and that comes from huge experience.
The point i am trying to make is that TG has used these same mid bass drivers despite the response dip at approx 1.2 khz
but i do not understand how is the design compensated for this dip..
He would not have used this driver otherwise..
PS : One driver where i do not see this dip is the Morel TiCW 638 Nd - do take a look and comment.
There are ups and downs - it will never be ruler flat but generally this midbass can be taken higher IMO..
PS2 : Am learning as well - so am open to constructive feedbacks / lessons..
IME, all these talks about dips, peaks, unevenness is more in the mind and we believe in what others say without giving any real time - real listening without bias. i will quote an example of mine last week of my own setup - i have my OB FR and H-frame sub connected and the subwoofer takes over below 180Hz (approx) and provides the low end lift. The FR are also good on low end and do provide me some lift. Last week i was listening and i found the sound to be quite good. Later i discovered that the subwoofer wire had come-off by accident due to the maid pushing the wire. I did not realize that until i saw them. I later connected and only after that noted the difference. Till that time without the sub also gave me Nirvana. So does the mind works tricks - i dont know that too. I can only say that my critical listening is not well developed and what i see is also very important than what i actually listen.
IMO, this midbass gets into cone break-up mode beyond 3KHz and does not benefit much. I will rather use the benefit of the low resonance of tweeter to takeup duty after 2KHz.
cant say about TG's attitude but $100 for a coating is huge by any standards.
I dont give much importance to dips if its not more than -3dB. In my measurement it looks like more of a cone resonance than response issue. I think that will go off after the driver is break-in for 100 hrs.
IMO, this midbass gets into cone break-up mode beyond 3KHz and does not benefit much. I will rather use the benefit of the low resonance of tweeter to takeup duty after 2KHz.
the satori mid-range shows an resonance @ 1200Hz as measured by me though very minor. This was with only 20% stuffing in a sealed enclosure. I shall add 100% stuffing and check again if they are gone and report later. This could also be because of the new driver and the voice coil not very free moving. Maybe some breaking will help them to settle.
If you look at the satori SPL and its associated minimum phase (black) and excess phase (blue trace) you can see the cone resonance at 1200Hz which needs to be addressed. The minimum phase stays at 0 deg till around 2KHz after which it looses control. I will first try with a crossover of 2KHz and see how well it integrates with my tweeter. The resonance issue will be addressed later by using a series notch, stuffing or something similar.
If you look at the satori SPL and its associated minimum phase (black) and excess phase (blue trace) you can see the cone resonance at 1200Hz which needs to be addressed. The minimum phase stays at 0 deg till around 2KHz after which it looses control. I will first try with a crossover of 2KHz and see how well it integrates with my tweeter. The resonance issue will be addressed later by using a series notch, stuffing or something similar.
keith_correa
Well-Known Member
That resonance (cone edge to surround??) at around 1.2K is very narrow band and is nothing to worry/obsess about IMO. It probably will not be audible at all except maybe if one is a bat. Even then, probably not! 
The boxes were delivered last weekend and this is how they look
I have assembled only one box, for designing the crossovers. The final buffing will be done just before delivery.
I did some measurements after mounting of the raw drivers and simulated a crossover network suitable for this speaker system. The drivers are not broken-in much and may have around 15 to 20 hrs of listening in my first iterations. Check out graphs below,
Cross-over frequncies 200Hz, 2150Hz as per simulation.
The mechanical Q is well damped by the line and stuffing and the resonance peak of woofer is very low.
Crossover components will be purchased later in this week.
Edit:
Earlier response curves were with near field with microphone very close to the driver dust cap. This response have advantage of eliminating the room from your measurement. Challenges are to retain the same mic position for all the 3 drivers.
I again simulated with the mic position @ 1 meter from the driver axis and simulated the crossover with the same component values. Below is what i get,
Ignore the bump at 74Hz as its my classic room mode hump and nothing can be done about it other than room treatment.
I have assembled only one box, for designing the crossovers. The final buffing will be done just before delivery.
I did some measurements after mounting of the raw drivers and simulated a crossover network suitable for this speaker system. The drivers are not broken-in much and may have around 15 to 20 hrs of listening in my first iterations. Check out graphs below,
Cross-over frequncies 200Hz, 2150Hz as per simulation.
The mechanical Q is well damped by the line and stuffing and the resonance peak of woofer is very low.
Crossover components will be purchased later in this week.
Edit:
Earlier response curves were with near field with microphone very close to the driver dust cap. This response have advantage of eliminating the room from your measurement. Challenges are to retain the same mic position for all the 3 drivers.
I again simulated with the mic position @ 1 meter from the driver axis and simulated the crossover with the same component values. Below is what i get,
Ignore the bump at 74Hz as its my classic room mode hump and nothing can be done about it other than room treatment.
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