Help with MLTL

Long time builder, long time reader back from a nearly 20 year hiatus, asking for help with Hornresp on win7 x64. Or even better, short term:rolleyes:, would a Peerless SDS-160F25PR01-08 work well in a MLTL? Specifically from 400Hz and down. Will be actively crossed w/ miniDSP, zobel added once I get this part figured.

Power Handling (RMS) 60 Watts Power Handling (max) 120 Watts Impedance 8 ohms Frequency Response 35 to 20,000 Hz Sensitivity 87 dB 2.83V/1m Voice Coil Diameter 1"
Resonant Frequency (Fs) 42 Hz DC Resistance (Re) 7.1 ohms Voice Coil Inductance (Le) 0.41 mH Mechanical Q (Qms) 2.97 Electromagnetic Q (Qes) 0.58 Total Q (Qts) 0.49 Compliance Equivalent Volume (Vas) 1.04 ft.³ Mechanical Compliance of Suspension (Cms) 0.12 mm/N BL Product (BL) 6.64 Tm Diaphragm Mass Inc. Airload (Mms) 13.7g Maximum Linear Excursion (Xmax) 6.05 mm Surface Area of Cone (Sd) 141 cm²
Any suggestions, comments are welcome

Thx Mike


2009-02-24 12:32 am
I agree with GM on both counts, not that he needs or wants my agreement, you understand.:) But be sure you have truly representative driver specs, rather than relying solely on those from the manufacturer you listed, when modeling with Martin's worksheets.
Mostly doing a prelim on them for starters. Haven't found any user tested specs on a properly broken in driver as of yet, have extensively searched.

Experience tells me to check all referenced specs against real world and thus if nothing is found I'll be the one to discover them for all ;)

The ultimate conclusion to this will result in a wwmtww design.

Unless anyone would suggest the upper range being mtm instead. Or the use of a Tang Band W4-1337SDF and an Airbourne RT4001? Crossover (passive) is done.. and corrections for the most part, you know voicing :eek:

Outer two will be isobaric MLTL with either the inner two being AS or another MLTL (room gain effect this decision). Total of 6 drivers (the same) actively crossed x3 amps. This combination properly implemented could be used in cardioid bass and loading a room better in the low bass range and baffle diffracton loss. Two top, two bottom spread out would get me into that "no less than one third from ceiling" which in my own tests have shown where nodes occur in a typical room resolves. Add a sub (or 2) to this setup and effectively filling that narliness at the bottom. Keeping in mind the driver spacing @ crossover point between mid and inner two midbasses ~20" center to center from the mid.

Yes it's tall, actually even taller when it's also raised another 6-8" or so off the floor (tweeter heigth 35-37"). About 6' or so I'd say

This design was the next set of speakers I would have built so many years ago before my son got sick. He's not right, but better, I'm better but not right :snickers: He looovves music so I did a little fullrange point source with a small sub for his bedroom recently. Nice old 4" Panasonic drivers, gotta love them. Puts him with about 100dB in room which is insane, I make it less than 75 for normal listening levels. Don't want hearing loss cause dad wasn't paying attention :)

also to note: I haven't had a decent pair of speakers since then. Aside from headphone use and my Monsoon PM-9 computer speakers, I've got an itch that is beyond reproach :gasp:
After a major fiasco with the car this last week my budget got cut. Thankfully I can do most auto repairs so that saved me from having to abandon this altogether, albiet a different design.

New thoughts of what to make instead... hmm well not what I wanted, but what I was ultimately thinking to make for my son. Using the Monsoon PM-9 planar driver for the mid, dipole or cardoid setup, room to play with either here in an MTWW setup. Few months back did a some actual tests on them, altho without calibration, measurements etc. Looks like the top end would need to be crossed fairly high, say 5k5 - 6k roughly. It's diaphram is roughly 3" (78mm), with a 4.5" (115mm) heigth. Will remeasure all again, but for real than some prior mental exersize. Bought a UMIK-1 when purchasing a minDSP for some accuracy this time around. Back in the day I had access to most of this stuff on the job, just really sucked when you had to put everything on hold because another engineers had to keep it in their custody for as absolutely long as possible :rolleyes: Didn't need the Ivey spectrum analyzer per se but did need the MK mic. At $800 cal'd, she said no.

haha no suprise there ;)

(side board)
Funny to think of Pro's neglecting to take the cal. chart into consideration. Or even the real difference in what a real calibration is vs the turn of a pot to fix this or that. Or the reason the company would not be purchasing (scratches head) TEF waterfall analyzer (don't think correct, but it was along while ago) because, 1. the results were difficult to understand / conflicting / confusing. 2. howto apply what is displayed. 3. cost, it was $27k... and 4, I was the only one who appearently did (so told by management), but the "old school guys" didn't, so that would cause other issues... BTW, #3 didn't apply, we were flush with cash. We had the TEF for two weeks which I managed to use to build my last speakers. Got awesome results for little money using carefully selected drivers. That was mmtmmm with an ISO sub built in. 5/5"full range drivers coupled with Pro 1" JBL titanium domes tweets. Had four left over from The Cove. Not bad at the time, the newer variants can still be had for around a buck fifty each. Sub was intentionally designed to be quarter wave, but we didn't have the inspiring efforts as Martin (et al) has done. Funny to think how bloody close I got. Was VERY deep, F3 in room measured 23Hz and fairly clean at a moderate listening level. Crossovers were a PITA, a 3.5 way but not in the normal sense and was not finalized befor their demise (tears). Crossovers from them were saved and will be repurposed. :) Lots of metalized polyprops, various metal film and Dale precision power resistors, a fair assortment of aircore inductors minus the larger ones are larger lamenated iron core, with some various ferites. I got parts, trust me. These will work for the basic design, if not long term

(/side board)

Have REW and HOLM installed. Missing anything some would consider vital or essential? Suggestions thoughts from others whom may have experience with the planars?

I'm sure I'll be chiming in on the MLTL, bought extra woofers to test a couple of ideas and in case one or two just aint right
Decided to go with a Airborne 20021 for it's speed, limited low end but stellar top end would match up wonderful @ the crossover needed. Have to pad it way down tho, off the top of my head ~7dB.

Now if I can find #2 of 2 toroid power transformers for each of the quad ch amps. Bought them some 25 years ago just for a project like this. Do believe it's in Storage unit #2, haven't seen that stuff in like 8 years LOL It's really there, just gotta find it.

Everything will be coming in throughout the week.