PD1850 vs PD1851 - Diffs/Advantages/Disadvantages

pfly wrote: Elliot Thompson wrote: levyte357- wrote: Elliot Thompson wrote: Usually 18-inch drivers that offer high sensitivities mean they offer more mid/kick-bass than lower sensitivity 18-inch drivers. That may be a good or bad thing pending on what you are looking to achieve. Best Regards, The V18-1000/1850 loaded in, compatible horn loaded cabs, will do the lowest sub notes, but with a peaky response, until at  least 4x cabs in one stack.. Warmer, less sensitive, lower BL drivers, have flatter response, but lower SPL at lowest notes. If you used the PD 186 it would go even lower than the PD 1850/V18-1000 in a horn. This is due the PD 186 was designed to go lower based on its TS Parameters. A Peaky response is usually due to the limitation of the cabinet size. It is common with large woofers housed in small horns, reflex, and/or sealed enclosures. This is why some resort to smaller drivers where the loudspeaker chassis does not take up 50% of the cabinet it resides in. A woofer in a cabinet that delivers a flat response tells you the driver is in a optimum chamber and, will not need to do a lot of work (due to excessive equalisation) to achieve the a lot of SPL. A good example is a high frequency compression driver on a large exponential horn. Best Regards, I like to think folded horns (scoops included) as a larger box that is just split into pieces that two to four people are able to lift.  If they are thought like this, if you get peaky response from one box but four or six boxes next to each other smooth it out, then it works exactly like intended. It is not just that peaky response means the box is not optimized for particular driver. When enough boxes are used, those "tight" drivers start to show what they can do.

The majority of old small folded horns (scoops included) were designed operate with a minimum of four bins. The DJs I know in the States & the West Indies that use such bins would not use less than 8 - 18 bins.

I might add small folded horns (scoops included) are limited to the horn's length. Since those boxes are designed quarter space, you can only get louder by having a larger mouth area once you exceed four bins. However getting a flatter response the lower you go requires a longer horn path (Terror Horn & Lab Sub) which small folded horns (scoops included) cannot offer.

Since the length of the horn determines the lower frequency cut-off point and, the driver requires a certain amount of space in order to create lower frequencies, using a small horn will not give you a flat response used in multiples if the if the length of the horn is too short for the driver to deliver the given frequencies. You will attain a peak above the horns cut-off point and your dB level will decline beyond that.

The biggest misconception are many running about with a bunch of small horns assuming  the frequency will go lower and flatter by quadrupling the amount small horns. You cannot get lower with a great amount of SPL below the length of horn's cut-off point.

Many have tried using heavy equalisation to force lower frequencies in such cabinets. The end result is finding them selves constantly repairing blown woofers.

Best Regards,