Hello. I have built a few smaller speakers, as well as a pair of overnight sensations (I do love them). I am beginning my plans for a new pair of floorstanding speakers and I have developed some questions.
I do not see that many recent DIY MTM/MMT transmission line speakers (and much of the calculation/papers are done using a single driver TL speaker). I understand there is a tritrix kit on Parts Express but I think the enclosure looks horrendous. My questions are:
1) When adding multiple drivers to a system such as a MTM or MMT or even a TMMW configuration, what happens to the T/S parameter of the system as well. Does the Vas of the system increase with the additive speakers? Thus a MTM TL speaker would have to have a massive area tube for 1/4 wavelength?
2) Whats happens to the systems Qts as we add more drivers? do they sum/add or do we just take the high and low - or is it more complex as they meld together making their own pseudo Qts
3) Does adding speakers in this manner affect the resonance of the system or is that determined by the speakers.
4) When selecting drivers for a MTM do want the Qts of the Tweeter and the Mid to be close so that the lobing of the speakers are similar?
I do not see that many recent DIY MTM/MMT transmission line speakers (and much of the calculation/papers are done using a single driver TL speaker). I understand there is a tritrix kit on Parts Express but I think the enclosure looks horrendous. My questions are:
1) When adding multiple drivers to a system such as a MTM or MMT or even a TMMW configuration, what happens to the T/S parameter of the system as well. Does the Vas of the system increase with the additive speakers? Thus a MTM TL speaker would have to have a massive area tube for 1/4 wavelength?
2) Whats happens to the systems Qts as we add more drivers? do they sum/add or do we just take the high and low - or is it more complex as they meld together making their own pseudo Qts
3) Does adding speakers in this manner affect the resonance of the system or is that determined by the speakers.
4) When selecting drivers for a MTM do want the Qts of the Tweeter and the Mid to be close so that the lobing of the speakers are similar?
1. No matter what the box design is, TL, vented or sealed, for a given woofer or midwoofer and a given bass response (f3, for instance), the required box size will double in volume if two drivers are used. Relative to a single driver, Sd and Vas double, and if those drivers are wired in parallel, Re and Le are cut in half. If those drivers are wired in series, Re, Le and Bl are doubled.
2. The required 1/4-wavelength resonant frequency for a TL is determined only by its length (and taper ratio if tapered), not its area (or volume) and is the same for a single or double-driver setup, as fS and Qts are unchanged.
Your #3 question is essentially answered by what I said for questions 1 and 2. Your #4 question doesn't make sense (to me).
Paul
2. The required 1/4-wavelength resonant frequency for a TL is determined only by its length (and taper ratio if tapered), not its area (or volume) and is the same for a single or double-driver setup, as fS and Qts are unchanged.
Your #3 question is essentially answered by what I said for questions 1 and 2. Your #4 question doesn't make sense (to me).
Paul
I want to add to my post #2 comments. If a TL is NOT an ML-TL or ML-TQWT, the line's 1/4-wavelength resonant frequency is the sole tuning factor and will be the system's tuning frequency, independent of the driver(s)'s T/S values, and that 1/4-wavelength resonance will be determined by the line's actual length if not tapered or by its effective length if it is tapered. In an ML-TL or ML-TQWT there is also a port, and the system is tuned partly by the 1/4-wavelength resonant frequency from the line's length, and partly by the port.
Paul
Paul
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