A three-way DIY project with JBL 2216ND or with 2235H?

[ramin_audio]

You’re going to have to do a lot of trial and error back and forth if you opt for a passive network.

If you know how to use REW driver measurements can to saved and exported to a crossover program. REW files can be emailed. When yoh get to that point if you wish contact me off line and l can look at your network proposal in Leap V.

http://www.troelsgravesen.dk/Diy_Lou...r_Projects.htm

Hello Ian,

I can do SPL vs. Frq and impedance measurements using OmniMic V2 and DATS V3 Dayton Audio.
I actually was successful building an xo for my last year project using VirtuaCad XO sim.

Last month I bought SoundEasy V30. But I haven't had the time to figure out how the software works.
They say it needs XLR microphone and an external mic preamp/soundcard!

I would love to send measurements and my xo drawings via email.

Right now, I am trying to figure-out the best cabinet for the woofer.

I want to build something like the 2-way JBL monitors (like jbl 4367) but without the horn section.
For the upper drivers I build separate cab(s).

--------------------------------------

So, what do you guys say about a cabinet volume of 170L tuned to 35Hz (4" Diameter, 1.68" long), for JBL 2216ND?

Thanks

[ramin_audio]

As other have suggested a 8" or 10" would probably be a better match, but that does not mean it cannot be made to work and sound nice. A 4-way also has it own challenges.

EDIT: this topic seems relevant: https://www.diyaudio.com/community/t.../#post-7302798
That looks like a very good mid.

EDIT2: also very relevant, and you could probably just replace the two 8" woofers with a single 15": https://vcllabs.com/vcl-ex27/

Thanks for the comments, esp. these two links. I am studying them.

[ramin_audio]

Since we are talkin 4 ways somethin similar to XPL-200 especially with dome mid and tweeter. Upgrade to an 8 or 10

https://www.lansingheritage.org/html...s/1989-xpl.htm

Rob

I have a pair of XPL-200 in mint condition.

I love them. Gave them to my dad. He is running them with Accuphase E-380 and magnum dynalab tuner. He likes FM and loves the sound of them.
Personally, I am sure they will go a next level if I rebuild the xo with modern caps and coils.

One of the reasons I bought these beryllium tweets and mids is the XPL-200.

[Ian Mackenzie]

With the 2216nd Greg Timbers said the M2 was already large (as an assisted system).

As you have seen from the simulations the trade off is enclosure size versus additional power amplifier input. With your passive crossover low dcr inductors are going to still add some dcr in a 4th order network. This will impact on the QTS’ and will require at least 140 L (see S4700 enclosure tuning) enclosure to avoid peaking in the bass response.

If you look at the legacy Technics 15 inch system that is profile of your proposed system.

https://images.app.goo.gl/8G42E8AEpJoRzp6AA

My advice is evaluate several different tunings in your room before settling on the final tuning. I would recommend that you also evaluate incorporating a Dirac enabled preamp like a Nad Master Series pre amp to help you fine tune the low end and clean up mid range masking due to room resonances in the 200-400 hertz region. This approach will simplify the design of the woofer low pass filter in that you can shoot for a text book bass reflex tuning and 4th order acoustic slope. You could also incorporate an assisted LF tune ng just like the M2. Use Dirac is customise the in room response. Greg has endorsed this approach.

[Ian Mackenzie]

https://hificompass.com/en/reviews/b...p-6-and-m74s-6

[ramin_audio]

With the 2216nd Greg Timbers said the M2 was already large (as an assisted system).

As you have seen from the simulations the trade off is enclosure size versus additional power amplifier input. With your passive crossover low dcr inductors are going to still add some dcr in a 4th order network. This will impact on the QTS’ and will require at least 140 L (see S4700 enclosure tuning) enclosure to avoid peaking in the bass response.

If you look at the legacy Technics 15 inch system that is profile of your proposed system.

That Technics speaker looks awesome! It must be a very good speaker.

I can make a very similar cabinet with thick walls and braces!
So, is an internal volume of 170L (tuned to 35Hz) large enough?

My advice is evaluate several different tunings in your room before settling on the final tuning. I would recommend that you also evaluate incorporating a Dirac enabled preamp like a Nad Master Series pre amp to help you fine tune the low end and clean up mid range masking due to room resonances in the 200-400 hertz region. This approach will simplify the design of the woofer low pass filter in that you can shoot for a text book bass reflex tuning and 4th order acoustic slope. You could also incorporate an assisted LF tune ng just like the M2. Use Dirac is customise the in room response. Greg has endorsed this approach.

My budget does not allow any more amp/preamp!
I have already drained my audio budget buying my current system!

My basement is large enough and I can treat the walls and put carpet on floor...

[Ian Mackenzie]

My suggestion is aim for a 200L -230 L net volume allowing for bracing (-10% of the volume and the fibre glass wadding on the walls +10%). Use only 1” fibreglass . So it might have internal dimensions of 58cm x 95cm 38cm. What ever works for you.

This might seem oversized. Read on.

You can simulate this stuff to death and attempt to make allowances for losses. It’s easier to over budget on your enclosure size. I looked at the large warm signal T/L parameters of the 2216nd and allowed for some dcr in your woofer passive filter. The inductors in the S4700 passive network had 0.9 of an ohm dcr. Thats bad! The only way to achieve damping is with a lower tuning with larger enclosure volume.

ERSE make some very good laminate low dcr indictors. Air core inductors are going to be hellishly expensive with a low dcr.

The tuning of 29 hertz has an f3 of 30 hertz. A smaller enclosure like that used for the S4700 was tuned to 35 hertz. It didn’t go low either.

Most of the heard bass will be purely from the 2216nd woofer with this tuning
which is exactly what you want. Just like the medium format 15” legacy systems. The port will really only come into play on deep bass. The 2216nd has immense linearity with the differential drive motor so the cone can move a lot of air with low distortion.

A tip.
I suggest you port the enclosure from the front panel so you can place the enclosure close to the front wall. This will reduce the 1/4 wave length reflections off the front wall. Pulling out the enclosure will reduce the bass overall due to boundary reinforcement but you will get uneven mid bass with deep troughs. This can result in losses of important musical information. What happens is the 1/4 wave length sine wave reflects off the front wall and on return resembles a 1/2 wave length and causes a 180 degree phase cancellation with the woofer. Yes it does. A 40 cm deep enclosure on the front wall will have a cancellation at 215 hertz. Pulling out the enclosure 20 cm will cause a cancellation at 143 hertz.

2nd tip.

Don’t overthink your design before you built it. It won’t make it perfect.

Aim to get the bass enclosure going first. Then experiment with the mid and tweeter sub baffle. Start off with a basic network and adjust the levels by listening. Then start experimenting with the crossover.

You might try crossing the dome mid up higher than a classical design. For example 700-7000 hertz. Why? This is where the important information is that the human ear assigns much effort in localisation and spatial accuracy. Above 7000 is what recording engineers call “Air”. Many of the fundamentals in musical instruments occur in the 150-700 hertz range. The overtones can occur at the 2nd, 3rd, 4th , 5th harmonics. Ideally if this coverage can be uninterrupted it’s a good thing. Phase shift and a gradual uninterrupted shift in the power response towards high frequencies.

Looking at the mid dome review it’s quite a capable driver up further than 3500 hertz which is typically the crossover point of a 3” dome because of the beryllium diaphragm. If you read the review there’s commentary from the designer on how he came up with the different diaphragm choices and what worked and what didn’t. Ideal measurements were not what determined the diaphragm construction or the geometry.

You might experiment with different tweeter crossover options to see what sounds best.

I don’t know if you have built a bass reflex loudspeaker before? As the driver goes up to like 1000 hertz the side front & rear panel need to be inert as possible in the pass band. Use birch ply or one inch mdf. Don’t go crazy on over engineering the enclosure. You won’t be able to move it into your basement. Brace the panels in 1/3 the length of enclosure. You can mill out the bracing from mdf like the M2. Add an additional layer on the lower section of the front panel to reduce resonance breakthrough.

[Robh3606]

The ERSE's are a good choice I kept the inductor DCR for the inductor pair to .650 using them.

Rob

[Ian Mackenzie]

It’s all up to the thread owner now. The erratic nature of this forum now makes it virtually useless. The change or fixes from the AK officials could have been scheduled and communicated to all LHS members so we weren’t put in this crazy situation.

If anyone wishes to contact me use the email address in my signature.

[ramin_audio]

Yes, I have been trying to post here, but the site keeps crashing on me. LOL.
I have saved your email Ian and will email you. Thanks.

This is going to be an excellent speaker project.
I am away for a week or so, and will start building the cab for the woofer in middle of June.

So, I am going to stick to my previous design but will increase the depth to 33".
The side wall will be 1" thick MDF. All other walls will be two layered (3/4" thick MDF and 3/4" thick multi-core birch).

So, the internal volume will be: (18" x 24" x 30") = 12960 inch^3 = 212.4 L.

Is that large enough?

As for the inductor, I have used these:
https://www.solen.ca/en/products/sol...-litz-inductor

Aren't they even better than the ERSE's?

[Robh3606]

As for the inductor, I have used these:

https://www.solen.ca/en/products/sol...-litz-inductor

Aren't they even better than the ERSE's?[/QUOTE]

With Inductors air cores you have to look at DCR. Compared to cored they are typically higher simply because more turns are needed to reach the chosen value.

With cored less turns lower DCR however you have Hysteresis. Select a power rating consistent with what you will be using to power the system.

Don't make any decisions until you have finalized your schematic. Inductors can be very expensive and sometimes it's difficult to find your exact value.

Just remember you can go up to the next value and unwind down to the desired one

So you need 4.3 cant find it see a 4.7 get them and just strip some off and measure as you go.

You can also re-run the simulation to see how significant the change would be and go from there

Rob

[Ian Mackenzie]

One idea that occurred to me was that you could mount the mid dome and tweeter over the front of the woofer using an aluminium extrusion. While obviously not time aligned it would behave more like a point source. Some ceiling home theatre loudspeakers are designed this way.

Phase compensation by shifting the mid dome crossover point will smooth the crossover point transition. It could be argued that moving the mid dome some 350- 400mm above the woofer centre poses a bigger challenge to network design trade offs.

The actual delay on the woofer is minuscule relative to the wavelength at the crossover frequency.

This approach may offer less overall diffraction and reflection from the mid dome and the tweeter off the main enclosure. This is often the consequence of attempting to physically time align the acoustic centre of the drivers. But listeners tend to pre conceive the notion that drivers must be physically time aligned unaware of the invisible problems created by attempting time alignment. Would the drivers block sound or cause reflections from the woofer? The answer to that is in the listening.

The audibility of diffraction and early reflections is sometimes associated with ghosting or a loss of focus in imaging where the ear detects and maps the impact short reflections after the arrival of the direct sound. These reflections

Using a round over to mount the drivers would minimise edge diffraction on the driver face plate.

[Ian Mackenzie]

To illustrate the effect of adding 0.9R dcr of the crossover inductors in the S4700 l
Have prepared the pocket handheld simulation below. Using a TL modelling l have updated the parameters to reflect the added dcr.

App Speaker Box Lite.

I believe this is a close approximation to the 4700

Of course this sim does not incorporate your room influence

Increasing the enclosure volume to 200 L adds bass extension.

[Ian Mackenzie]

Next l looked at the Jansen Permite inductors with a reported low hysteresis. A total dcr of 0.3R is obtainable. The power amp
Damping Factor is rated at 40.

The attached sum of an optional tuning at 31 hertz in 195 L
A larger enclosure may prove difficult and heavy to control panel resonance up to 900 hertz.

These are the compromises a loudspeaker builder must face.

I do however believe that the additional enclosure volume will offer improved tonal balance without the mid bass peaking of the smaller enclosure when falls off quickly below 40 hertz.

[Ian Mackenzie]

I would not build the woofer crossover out of expensive parts until you are fully satisfied with the overall results. This is why l suggested the Jantzen inductors. I would use low cost capacitors initially for this reason.

Attempting perfection on paper prior to assembly and ordering expensive crossover parts can be premature when several revisions may be required. Your room, your preferences and other unforeseen developments may affect the final crossover network. Simply use low cost parts during the development your loudspeaker.