There are two different kinds of 15" + horn hybrid speakers.
The first group - 15" drivers optimized to play from mid-bass to lower mid-range.
For example older Altec 15" driver like: 803a/b, 515, 515B, 604 Hollywood/B/C/E.
These drivers have great speed, tone and texture in a male vocals and cello range. But they don’t play a deep bass.
They good for vocals, classical and jazz music.
The second group - more modern 15" drivers built for rock and roll and electrical bass.
Like later Altec drivers: 416, 604K and most of JBL drivers used in speakers like: L300, 4430.
These drivers play deep and powerful bass but flat in a male vocals and cello range.
For example, I heard JBL L200, L300 and 4430.
The older model belongs more to the 1st goop, L300 and 4430 belong to the 2nd group.
The first group - 15" drivers optimized to play from mid-bass to lower mid-range.
For example older Altec 15" driver like: 803a/b, 515, 515B, 604 Hollywood/B/C/E.
These drivers have great speed, tone and texture in a male vocals and cello range. But they don’t play a deep bass.
They good for vocals, classical and jazz music.
The second group - more modern 15" drivers built for rock and roll and electrical bass.
Like later Altec drivers: 416, 604K and most of JBL drivers used in speakers like: L300, 4430.
These drivers play deep and powerful bass but flat in a male vocals and cello range.
For example, I heard JBL L200, L300 and 4430.
The older model belongs more to the 1st goop, L300 and 4430 belong to the 2nd group.