Dual Woofer Floor Standing Speakers

[sanwill]

I started my first speaker design course in Feb. '21 and have since made 4 pairs of speakers including an awesome 12" sub. I've got the bug!
Now, I feel up to a new challenge and I am looking for some advice as noted below. First, the project: floor standing, high-end speakers with 2 woofers each + tweeter + bass reflex, high end wood veneer finish. Advice needed:
- how to design the dual woofer system (I can do all of the design aspects it is just I have found nothing to guide me on 2 woofer systems)? Am assuming wired in parallel, have read info that they should be in a separate box self-contained inside the speaker box itself? Vas is 2x so that is what I enter into design calculation software (WinISD)?
- type of crossover? Next course I take will involve Xsim. Is this all I need to do and can figure it out with some knowledge and experience?
- am leaning towards Dayton Esoteric woofers (5.5" or 7") x 2 plus higher end tweeter TBD. Any thoughts?
Tks

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[DeZZar]

- how to design the dual woofer system (I can do all of the design aspects it is just I have found nothing to guide me on 2 woofer systems)? Am assuming wired in parallel, have read info that they should be in a separate box self-contained inside the speaker box itself? Vas is 2x so that is what I enter into design calculation software (WinISD)?

If you are using two of the same woofers and just doubling them up for higher SPL/Sensitivity, better distortion etc then you simply model two woofers. No need modify any TS params. In WinISD you can choose how many of the same woofer to model for. They share the same air volume. You can go 2 way or 2.5 way with this sort of setup but it kind of depends on the performance of the woofers and tweeter together which works better.

- type of crossover? Next course I take will involve Xsim. Is this all I need to do and can figure it out with some knowledge and experience?

Type of crossover is ultimately driven by what the drivers are asking for placed in your boxes on your baffle. Its not really something you can just decide on simplistically up front. XSim or similar is only one part of the puzzle. You need to be able to take your own frequency and impedance measurements for the drivers in situ and then begin crossover design from there. It will likely take several iterations of a measurement, model, implement, listen, repeat cycle before you finalise a design.

When choosing drivers for a design I generally take a shortlist of candidates and use available data (or trace the frequency and impedance data from available charts) to simulate baffle diffraction for my theorized design and a crossover to test if the implementation will work

- am leaning towards Dayton Esoteric woofers (5.5" or 7") x 2 plus higher end tweeter TBD. Any thoughts?

A pair of the ES180TiA in 40L tuned to 34Hz will give you and f3 around 32Hz, take about 50watts for musical content down to 28Hz and produce just over 100db in output. The ES140 will give you less in every way and I wouldn't use them personally for this sort of project. You will need a tweeter that can cross fairly low to match up with these woofers (look for a resonant frequency in the range (500-800hz). Neither of the woofers appear to have overly smooth top end FR over the possible crossover regions so a slightly more complex crossover may end up being needed to get the desired result.

[Chris Roemer]

There are MANY quality drivers out there that co$t W-A-A-A-Y less than a quad of Esoterics. An experienced designer can achieve VERY high quality (w/proper box and XO design - like the popular Tritrix MTM), most likely MUCH greater than a "noobie" using top-end drivers. For your 1st attempt, I'd go with Dayton's (cheap) "Classic" series, or other low-cost drivers, just to get learning XO design. Your ears and wallet will stay much happier.

[andy19191]

- how to design the dual woofer system (I can do all of the design aspects it is just I have found nothing to guide me on 2 woofer systems)? Am assuming wired in parallel, have read info that they should be in a separate box self-contained inside the speaker box itself? Vas is 2x so that is what I enter into design calculation software (WinISD)?
- type of crossover? Next course I take will involve Xsim. Is this all I need to do and can figure it out with some knowledge and experience?
- am leaning towards Dayton Esoteric woofers (5.5" or 7") x 2 plus higher end tweeter TBD. Any thoughts?

A 2 way is a significant compromise in terms of performance compared to a 3 or 4 way. This is fine if you are constrained by money or space and happy with the trade-off. Opting for expensive drivers for 2 ways doesn't make much sense unless performance for the money is of little concern. For a first go at designing you should expect to get a few things wrong (we all did and many of us still do) which, as Chris mentions, suggests it may be wise to keep any enthusiasm for expensive drivers in check for a while. Not sure I would recommend budget drivers though but decent standard range drivers like Dayton reference, SEAS prestige, SB Acoustics non-Satori, etc... which tend to be a bit easier to work with compared to budget drivers.

Assuming you are sticking with a 2 way then the choices are likely to be a 2.5 way TMM or a 2 way MTM. If the speakers are positioned out in a reasonable sized room then a 2.5 way is possibly the better choice but on or close to the front wall perhaps an MTM.

The distance you sit from the speakers, the size of the room, the room treatment and the required listening level will dictate the required clean SPL. This influences the choice of 5", 6.5" or 8" midwoofers. However, the larger drivers with the higher cleaner SPL at low frequencies will not perform as well at the higher frequencies asking more from the tweeter and benefiting more from a waveguide.

You mention a subwoofer which should help significantly with a 2 way enabling the porting to lean towards maintaining SPL with a modest bass extension and decent speaker efficiency.

There are of course a number of other factors to consider before settling on a rough set of required parameters and searching for suitable drivers that get close.

[sanwill]

These are some helpful comments that provide good food for thought. Thanks a lot. This forum is a great idea!

[fpitas]

For what I think you're trying to achieve, the 3-way idea is a good one. Of course a 3-way crossover is even more of a pain than a 2-way.

[jhollander]

The next course should be how to measure drivers for speaker crossover design. This is where most people struggle. After that understanding crossover filters is another learning curve.

[sanwill]

Yes, I am starting to see that. Thanks for the tip.

[davidroberts]

You might want to look at doing a semi-powered speaker. You could build a proven 2-way speaker and then add a woofer section below it powered with a plate amp. Crossovers in the lower octaves can get expensive rather quickly. This option also reduces the learning curve. Plate amps comparable to MY receiver output wattage are rather inexpensive.