Dayton Drivers - ML TL - for a FM

[Hari Iyer]

Got an opportunity some 3 months ago to built a ML TL with Dayton drivers for a FM. Considering a 7" AL woofer and 1" AL tweeter from the Reference stable for this project.

I have already completed the TL BOX and have tuned it around 44Hz. Have yet to design the crossover and complete the Version1 built. Crossover will be as usual first order and will try for full phase coherence.

Would be able to complete them by mid next month for a initial impression with him. Will post images soon for benefit of DIY community of the simulations (BOX & Crossover)

Thanks for looking.

 

[Hari Iyer]

After a long break was able to complete the raw version of this speaker this week and listened to my reference track. Just one sentence about the subjective listening - I have never heard anything like this before in any situation. Just plain clean and detailed with a black dot imaging and resolution. No words can explain this as this need to be experienced. I am sure Ash will be more than happy with the outcome when he comes for the listen next weekend.

Cheers,

 

[Ash]

Thanks Hari. Now that I know your opinion , looking forward to visiting you shortly. [emoji106]


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[Hari Iyer]

As the woofer and tweeter is mounted on the same vertical plane, the timing difference between the woofer and tweeter voice coil is quite significant. This will be even more evident for a first order filter as there will be significant overlap of signals above and below the cross-over frequencies.

I first thought of rectifying this by putting the tweeter behind the baffle offsetting it by 40mm, but later realized that this speaker system is crossed very low at around 1400Hz and the wavelength of the tweeter will get obstructed by putting them behind the baffle for the offset.

Now i am thinking of mounting the woofer by extending the woofer section of the front baffle with an offset of 40mm. This will allow me not only the offset, but also the tweeter wavelength will coincide with the woofer at the crossover frequency. The woofer and tweeter are having their center 9" apart allowing me to do this.

More to follow.

 

[Hari Iyer]

After a long break, got into finishing this project which now is over 8 months old. There were many challenges after initial listen and measurements. Even though the crossover were phase coherent so to speak, they were not acoustically time alignment to exhibit phase coherence behavior. Hence I need to do out of box thinking to time-align the woofer and tweeter so that the lobing is in phase to the listening axis.

I initially thought of off-setting the tweeter behind the baffel by around 36mm, but quickly scrapped that idea as the crossover freq was around 1400Hz and that would impact the overlap between woofer and tweeter if the tweeter was sunked inside.

Hence i needed to bring the woofer ahead by around 40mm w.r.t. tweeter so that the woofer and tweeter center points were aligned in time. I needed to add felt for the tweeter as they were diffracting a lot and were exhibiting high and low Q behaviour in their pass frequency. I am still testing the felt outcome and will have to measure the SPL to confirm their effect.

Unfortunately, I do not have the microphone this week to measure the SPL, Step Response, Impulse response etc, as it was a loner to me from my stuido friend. I now will have to quickly purchase a good measurement microphone and preamp to confirm my findings and check phase coherence.

Here are some simulated and measured impedance from REW and XSIM for your reviews also am adding some images taken by me for your viewing,

This speaker can be bi-amped and bi-wired.

Thanks for looking,

Cheers,

 

[Kannan]

Dear Hari sir,

As I had sought your help on the same midbass drivers as a drop in for the Infinity, i soon realized the 7 inch midbass is not happy anywhere over 2 khz and sibilance from the overall system gets a bit difficult to control at the crossover point, assigning a steep slope to the tweeters or the midbass takes away the soul from the midrange frequencies.

This midbass sounds best when mated with the 4 inch widebander from the same series, The Dayton RS100-4. The crossover point can be at around 300/400 hz 2nd order.
This combo can easily run without tweeters, but for the sparkle the Dayton AMT (air motion) which has a f/s of around 5khz, crossed at around 9/10 khz (again 2nd order) will make it more complete. The RS100 can be set to roll off naturally without any LPF, at the most maybe attenuated after measurements for level matching with the tweeters.

This is what I am running in my car in a 4-way active setup (which includes a subwoofer aswell) and the front stage of the Dayton 7 inch with the Dayton 4 inch and the Dayton AMT sounds absolutely brilliant.

In that tweeter position for time alignment, what is the advantage of having it kinda boxed. Would it not be better to have no extending woodwork on the sides and have it open and the protruding woodwork above the tweeter to be tapered.

 

[Hari Iyer]

Thanks for your analysis and perspective about the Dayton RS-180 woofers. Also am glad to note that someone atleast reply to my posts.

If you had noticed the RS-180 SPL, the cone break-up mode is above 3KHz which is approximately one octave above my crossover freq which is 1400Hz. This published SPL matches 98% to my measured SPL (free air). Good job by Dayton Audio in maintaining consistent quality on the drivers.

https://www.parts-express.com/pedoc...0-8-reference-woofer-8-ohm-specifications.pdf

I am using a first order cross-over with a deep roll-off after 1500Hz faciliated by another inductor and resistor in parallel (similar to a BSC but non-textbook type) to avoid this cone breakup messing up with my mid-high response. The response of the woofer at 3KHz is 16dB down from the reference. At crossover point the response is exactly 6dB down from the reference (first order filter).

IMO if you are able to manage the filter phase accurately (woofer + tweeter) then you get a overall flat response at the pass-band and no phase related errors or distortion.

You can see from the below image that my filter phase (individual woofer and tweeter) and the combined filter phase is exact at 90 deg without any phase error. This gives an overall mellow sound to the speaker system and should be aimed by all diyers.

 

[mpw]

to my mind - it is better to put up pictures of the finished product rather than WIP ones as the WIP once can look rather - out of the box / gory.

why cant the tweeter come on top ?

and why cant you have a normal slope of the front baffle rather than the way you have made it now ?

as to graphs - not many of us understand or even care as long as the product sounds good enough.

that explains ..atleast in part... why there are few responses to your posts on this subject.

 

[Kannan]

to my mind - it is better to put up pictures of the finished product rather than WIP ones as the WIP once can look rather - out of the box / gory.

as to graphs - not many of us understand or even care as long as the product sounds good enough.

that explains ..atleast in part... why there are few responses to your posts on this subject.

Why not WIP pictures, and I don't see anything to be termed as 'gory'.

RTA, impulse responses, measurement, graphs, are what makes it possible to design a pair of good sounding speakers.

It does not pop out just by putting some driver in a box and powering it up.

Guess if someone shares some of these in his thread out of passion why not encourage it.

Understanding these parameters also helps in improving listening skills

 

[Hari Iyer]

why cant the tweeter come on top ?

I have explained this why it cant in my designs in many of my other posts. You anyway will not be able to understand as its a technical aspect. Also you are not aware about my discussion with the member who commissioned this project about this design and why its below the woofer and where he intent placing the speakers and at what height.

 

[mpw]

I have explained this why it cant in my designs in many of my other posts. You anyway will not be able to understand as its a technical aspect. Also you are not aware about my discussion with with the member who commissioned this project about this design and why its below the woofer and where he intent placing the speakers and at what height. So better not comment.

i dont care much for graphs as i dont listen to them.

You anyway will not be able to understand as its a technical aspect.

what a nice reply...:lol::lol:

yeah... good luck !

Why not WIP pictures, and I don't see anything to be termed as 'gory'.

RTA, impulse responses, measurement, graphs, are what makes it possible to design a pair of good sounding speakers.

It does not pop out just by putting some driver in a box and powering it up.

Guess if someone shares some of these in his thread out of passion why not encourage it.

Understanding these parameters also helps in improving listening skills

simple reason - Members like to see the finished product.

Nobody goes inside the kitchen as long as the food served is right.

and to complain that nobody replies to all the graphs put up - that was my blunt reply.

How many of the forum members here choose to care about graphs ?

does the prospective owner care ??

he or she cares only about how the speaker sounds and how it looks.

I made my comment directly on that and i stand by it.

 

[Hari Iyer]

Again one has to take the trouble of coming down and listen for at least 30 minutes to know how they sound. Mpw being just 12 km away from my home is not keen or interested to listen due to want of time. Leave alone thousands of other FM who are 100s of 1000 Kms away.

This is where the graphs help, where if you are technically aware of what makes a good speaker measurement you can arrive at some conclusion of how they would sound. ( Eg. Kapvin ,TCPIP)
No amount of objective graphs can substitute any subjective listening but neither do posting fancy photography of the Finished Product will tell you how they would sound.

Audio magazines like stereophile swear by both their subjective and objective measurements and millions do refer them for a perspective.

 

[jmascreen]

How is Dayton drivers performing compared to the fostex or peerless drivers which you have used ?

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[Hari Iyer]

How is Dayton drivers performing compared to the fostex or peerless drivers which you have used ?

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Daytons are very good at the lows and highs but some compression is seen in mid-range. Currently the drivers are not break-in. Only 10 hours are played in it. I expect them to be good after 300 odd hours.

Fostex excels in the mid-range which is not comparable to the Dayton's as of now due to breakin. Lows in Fostex are not as powerful and intense like the Dayton's but still very adequate for normal listening levels but i find the Fostex lows very natural and smooth/ deep too. Fostex cannot do HT duty without a sub added for HT. The highs in the Fostex has been supported by a Audiopur Ribbon tweeter and hence they are good too.

 

[jmascreen]

Daytons are very good at the lows and highs but some compression is seen in mid-range. Currently the drivers are not break-in. Only 10 hours are played in it. I expect them to be good after 300 odd hours.

Fostex excels in the mid-range which is not comparable to the Dayton's as of now due to breakin. Lows in Fostex are not as powerful and intense like the Dayton's but still very adequate for normal listening levels but i find the Fostex lows very natural and smooth/ deep too. Fostex cannot do HT duty without a sub added for HT. The highs in the Fostex has been supported by a Audiopur Ribbon tweeter and hence they are good too.

Thanks Hari, I am planning to use a fostex or other FR for my next project keeping the Dayton AL woofer for taking care of low frequency.

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[Kannan]

Daytons are very good at the lows and highs but some compression is seen in mid-range.

Sir next time if you want to explore, do try the RS100-4. Exceptional midrange.
Costs under 5k for a pair if bought in India.

 

[Hari Iyer]

Sir next time if you want to explore, do try the RS100-4. Exceptional midrange.
Costs under 5k for a pair if bought in India.

I dont have very good expertise in designing a box or a crossover involving a mid-range driver with woofer and tweeter and hence will try to avoid it totally. It will be difficult to built with first order filters due to huge overlap frequencies on either side of the mid-range driver. Will also need to have a good baffle design to accomodate 3 drivers without any lobing related issues.

The minor compression in the current design will be gone after the drivers are breakin after say 100 hrs or too. This is due to the metallic alunimimum dome tweeter which is a bit difficult to tame unless the voice coils are completely burned.

 

[Hari Iyer]

Past 5 years i have become wise by 1% in cross-over design and this was the right time to modify the crossover network for @Ash . This modification was first designed which took me 2 months to finalize. This was completed 2 weeks ago to my satisfaction as per simulation, measurements and subjective listening. Posting some images of the measured result,








As you can notice the tweeter is off-set from the woofer by 1.417" to delay the HF so that they are in-phase with the mids and the highs to prevent time-smear. This offset is important for achieving a clean step-response as displayed above without which it was very difficult to simulate. The cross-over was also modified from a parallel version to series version with just a total of 4 components. It can't get more minimalistic than that.

Thanks for looking.

 

[grindstone]

Thank you for posting and congratulations. Sometimes I think a diy speaker is never done in my own mind. The inset area looks angled (?) like you have made a small horn of sorts, acoustically, too. Some people find very open cell foam padding useful for sharp edges near HF drivers. I know you are done, but if one day you are restless to measure/hear something else, it is cheap fun and reversible/temporary.

 

[Hari Iyer]

Thank you for posting and congratulations. Sometimes I think a diy speaker is never done in my own mind. The inset area looks angled (?) like you have made a small horn of sorts, acoustically, too. Some people find very open cell foam padding useful for sharp edges near HF drivers. I know you are done, but if one day you are restless to measure/hear something else, it is cheap fun and reversible/temporary.

You are absolutely correct. The itch never dies and we always tingle around for some more improvement. My own DIY speakers have never settled past 3 years -